Hands On - Make: Electronics

Final Thoughts

2011-01-15T09:14:00.004-05:00

I apologize in advance for the length of this "final" post - final in quotes because who knows... there may be reason to occasionally revisit this blog with updates. But before I leave and move on to the next blog project, I'd like to put down some overall thoughts on this entire experience.

1. Should be required reading for all engineering students - I feel strongly that this book should be a standard textbook for all engineering students. I wasn't in the electrical engineering department, and my electronics training was mostly white-board theory and word problems in the back of chapters. One class did get us some hands-on time with a soldering iron and some resistors, but come on! I don't think any engineer should leave school without having this level of basic knowledge.

2. Should be suggested reading for all high school students - We have these lists of books that we tell every high schooler they should read - mainly classics of literature. But how often do we provide those students who have a strong interest in math and science with a list of good technology books? This is the book I WISH I had in high school - it may very well have changed the course of my studies. I'm happy with my chosen vocation, but it took over a decade out of university for me to find the time and the right book to get my understanding of electronics to this level. So... high school teachers and parents - try to buy a few copies of this for your high school library. (I'd donate mine, but the picture I'm including here should give you an idea of how I've abused my copy - the spine is peeling away and every other page is curled and written on.)

3. The cost to learn is high - I've read some comments about Component Packs 1 and 2 that Makershed sells... and there are concerns about the extra costs involved in finishing this book and its 36 experiments. Yes, the costs are high. But I'd estimate that for less than $300 you can have everything you need, including tools, to finish this book. That's the cost of a few college textbooks these days. It's also about the same cost as a LEGO MINDSTORMS robot kit which many parents buy for kids ages 8 and up. Consider this book, all the parts, and all the tools an investment in your education (or your child's education) and dive in. The tools will always be yours (and will last if you take good care of them). I simply refuse to worry about the costs I've incurred by working through this book. The education is priceless.

4. I missed a few... argh! - A few of the experiments I never could get to work... and a few others I skipped (especially towards the end). But the important part is that I understand! I get it. I have never understood electronics before the way I do now. I am still in shock that a book like this has alluded me all these years, but I'm glad it's here now, and I have shared (and will continue to share) both the book and the skills I've learned with teachers, parents, and students.

5. Learning by Doing... and Blogging - I've always had success learning a new skill when I'm actually doing something... I think most of us will agree that this method works. But I've also learned over the years that when I write something down... either my own explanation or at least my thoughts on something... it sticks better. By sharing my experiences - and reading your feedback/comments - I get to go back through each experiment again and further cement that knowledge. Maybe you'll consider doing something like this yourself - pick a book, create a blog, and document your work as you plow through the material. Reading a book is typically a solo endeavor, but I was surprised at how many folks tuned in to follow me work through this book. It was nice to know others were doing the experiments, getting their own results, and comparing them to mine... and those who helped me troubleshoot were a huge asset that you'll never get reading a book on a couch alone.

6. Never stop learning - I've already picked my next blogging project, but for those of you not ready to leave the book after Experiment 36, you'll be happy to know that the author appears to be providing more experiments in the pages of Make magazine... I've already seen in the previous 2 issues (23 and 24) that the author has included new experiments to perform with all new components to investigate. Rest assured, if one picks my interest, I may grab it, do it, and follow up here with a post.

Just a little over a year ago (Jan 6, 2010) I began this blog with the simple goal of using it to motivate me... if I posted my work for anyone to see, it'd light a fire under me to finish. I figured if I knew people were checking in on my status, it'd be hard to quit. Peer pressure can be a great motivator.

So, here we are... Jan 15, 2011. Make: Electronics finished.

Thank you, Charles Platt, for writing the book. I think it is one of the most valuable books I've ever read.

Thank you, Make Magazine, for putting it out there and creating those components packs that have allowed many folks to perform the experiments. (I also want to thank you for supplying a nice bundle of Maker Notebooks to give away as prizes - I've kept a few for my own personal use in future projects.)

Thank you, Readers... I've enjoyed your comments, and the results and obstacles you've shared. Good luck finishing the book (if you haven't already done so). I'll continue to receive notices when you post comments, and I'll do my best to reply to them. And please feel free to share (as a comment to this post) what you'll be doing next - any books of interest? Any project kits you've found that look interesting? Let me know.

James Floyd Kelly
Atlanta, GA
Jan 2011

Chapter 5 - Experiment 36

2011-01-14T21:06:00.003-05:00

I never could get my alarm system (Experiment 20) to work as planned, so I wasn't quite sure how to handle this last exercise. I've read over it 3 or 4 times, trying to understand the theory behind it... and it makes total sense.

What I find interesting about this experiment is the how much of the circuit from experiment 20 goes away when you bring in the PICAXE chip... letting the chip handle the logic rather than all those logic chips just makes sense from both a cost perspective and a losing-my-sanity one.

Take a look at page 201 at the circuit for Experiment 20... and then jump to the bit of code that allows the chip to determine if 7-4-1 has been pressed. It's a subroutine that's called by the code on page 313...and flashes of BASIC programming started flitting through my head. I was pleasantly surprised at how I understood the code and the logic behind it. Although I haven't rebuilt the alarm, it would be a rather simple matter to gut the box and recreate the alarm using just the PICAXE chip.

Some of you (myself included) may be wondering 'Why didn't the author save the alarm project for the PICAXE section of the book?' and, of course, I totally understand the reasoning - having worked through Experiment 20 and understanding how those logic chips work, I can both appreciate the power of MCUs and the author's making us go that route and doing it "the hard way" first.

Chapter 5 - Experiment 35 Completed

2011-01-14T20:53:00.004-05:00

Exercise 35 is pretty straightforward... you can see in the photo that I've added in the trimmer potentiometer to the circuit, making certain the center terminal connects to pin 5 on the PICAXE (logic pin 2).

I ran through a few tests, taking a reading with my multimeter at various settings... the debug window screenshot I'm including here shows the potentiometer maxed out at resistance - that's what the 255 for b0 is referencing.

I took about four different readings and compared the resistance readings on the multimeter to the chart on page 307... pretty close and the deviations are certainly due to the fact that this is an analog device and I'm turning a slot screw to increase or decrease the resistance... but I totally understand why the values you'd obtain with any trimmer would be linear in nature.

The final step was to update the code to allow the LED to flash faster or slower based on the trimmer... I'm including a video here that shows those results. Pretty cool stuff. Make certain you understand that paragraph on page 309 that talks about how you can use this information to control things with major changes being done in the code versus in the circuit.

Don't forget to read over the extras on page 310 that tell you about the different features that the PICAXE chips come with... I find it interesting that this little 08M chip has the ability to generate pseudorandom numbers and tones!

What's Next?

2011-01-13T20:42:00.005-05:00

I must have missed the memo!

In the last week, the following things have occurred:

1. Arduino The Documentary was released.

Arduino The Documentary (2010) English HD from gnd on Vimeo.

2. Make magazine Volume 25 focuses on the Arduino. (I'd estimate 50-60% of the magazine is directly related or involves the Arduino in some manner - I have the PDF/digital version on my iPad, but the print version should be out by Jan 25.)

3. Beginning Arduino from Apress hit the shelves (once again, however, I got the digital version)

4. Even The Ben Heck Show has coverage of the Arduino in this week's episode!

Given that the Arduino seems to have multiple spotlights on it for the month of January 2011, I guess this is as good a time as any to announce that when I finish the Make: Electronics book (this week, I believe) I plan on continuing forward by learning (and blogging) about my experiences with tackling the 50 projects in the Beginning Arduino book (#3 above).

Fifty projects?! I've scanned most of them and believe that I can do it... but I'm not setting a timeline and I'm most certainly not committing to doing all 50. A lot of it depends on costs (which I haven't figured out yet) of all the required components... and interest. The book looks great, but if I dig in and find myself getting bogged down or dissatisfied with the projects/book? Who knows?

That said... I've been waiting a LONG time to begin my hands-on with the Arduino. I know what it is... I know how it works... sort of. But I've never actually done anything with one. So...

I've ordered myself the Arduino Uno... and I may be ordering a few add-ons/accessories from the MakerStore shortly.

But because this is a completely different topic and book, I'll be moving this discussion over to a new blog - http://handsonarduino.blogspot.com - I've already got 2 followers, so apparently some folks have already jumped in even before the announcement.

As with this book, I'll be documenting my results - both successful and otherwise - and including photos and videos of my work. While I'm at it, I'll also do my best to build a running Google Spreadsheet that contains all the parts I've used (and where I bought them... and cost). Chime in if there's anything I've missed (or that you'd like to see me add) and I'll see what I can do...

Now... back to Exercise 35 and that PICAXE...

Chapter 5 - Experiment 34 Completed

2011-01-12T14:15:00.005-05:00

I've got a handful of videos for you here, but before I show you the final results I want to share a bit about the troubleshooting I had to perform to get the PICAXE software to properly download to the chip.

The first bit of troubleshooting was mentioned in the previous post - I simply needed to test to make certain the voltage regulator was providing 5v across the circuit... it was.

Next, I plugged in the USB cable to my laptop and to the stereo connector and clicked the Program button (to upload the program)... I got an error. (Of course.) The error window that popped up suggested I check to make certain I had the Options setting for COM port configured properly - I checked and it was (COM4) but then I noticed a button on the Option window that allows you to test the chip. The first screenshot I'm including here contains a set of short troubleshooting steps. I tested the voltage between pin 2 (the Serial Input Pin) and ground and it was 0. So far, so good. The second photo here shows that 0 volts is being read and the dark green dot (on the laptop screen) is turned off.

Next, I clicked on the dark green button (it turns to a bright green) and the voltage jumped to almost 5v (see the next photo).

So that checked out, but for some reason the program still would not download to the chip. It took me about thirty seconds to figure out the very simple problem... and here it is:

Make certain to insert the USB Cable jack into the Stereo Connector until you hear it CLICK! I didn't have it pushed all the way in (although it felt that way) and the final bit of movement requires a tiny bit of extra pressure to fully seat the jack.

After that... the program downloaded just fine. The first three videos below are all variations of the first bit of code on page 301. The first video is with the code downloaded and the USB cable still connected. Second video is with the USB cable disconnected. The third video just shows the LED blinking faster after the code has been changed.

The last video shows the results of the second program from page 304.

Chapter 5 - Experiment 34 Circuit

2011-01-11T17:38:00.003-05:00

I got to work on wiring up the circuit that will be used - the most time consuming part was simply soldering some wire so it touches both leads (twice) on the stereo socket, but I think I got that part done correctly.

After wiring up the circuit, I ran a voltage test to make sure the voltage regulator was working, and one of the photos shows the 5v clearly.

There is an error in the book (verified by the errata page) with a resistor shown at the bottom of the schematic - ignore it... no resistor goes there.

Up next - typing up the code and then uploading it to the 08M.

Note: You may have noticed in the last photo a clear box of jumper wires. I purchased a box of 150+ pieces for about $10 at a nearby electronics store and I love these things - should have bought a box at the beginning. You can see in the other two photos that I've relied heavily on these pre-cut and pre-stripped wires, ignoring any sense of style when it comes to color.

Chapter 5 - Experiment 34 Driver Installation

2011-01-08T22:10:00.007-05:00

Before you get too far into this experiment, you must make certain to install the special USB cable driver on your computer. The USB cable fools the computer into thinking it's talking to the Picaxe chip with an old serial connection (versus actual USB).

The instructions for doing this can be found on an included PDF file in the ZIP file you download, but I didn't have as easy a time installing it as the instructions suggest, so I wanted to walk through this in case there are others who encounter this issue. (Specifically, the screenshots in the PDF do NOT match what is seen on a Vista computer - they do include Windows 7 steps but my limited memory of using XP has me thinking the screenshots also DO NOT match the XP operating system - please feel free to correct me if you find the PDF is correct for XP.)

First, you need to be aware that I'm installing the driver on a Window Vista operating system, so these instructions may not match exactly with your OS... but I think you'll be able to get the basic idea of how to get around any hiccups you encounter.

The first thing you'll do (after downloading the driver - see previous post) is plug in the USB cable. My Vista laptop automatically detected it as seen in the first screen capture I'm including here. As you can see, it recognizes the cable as an AXE027 PICAXE USB device. But whereas the instructions show a nice little pop-up window that asks you to specify the location of the files, I never got this - I got an error message saying "Device Driver Could Not Be Found" and my only option was to click OK. So... it's off to the Device Manager (from a previous life as an IT consultant, I know my way around just enough to be dangerous and figure things out...)

Open Device Manager by clicking Start, and then right-clicking on Computer and choose Properties. Click on the Device Manager option in the left column of the screen. As you can see in my 2nd screenshot, there's an exclamation point next to the device telling me there's a problem.

Next, I right click the AXE027 PICAXE USB device and choose Properties. On the window that appears, I click the "Update Driver" button and a screen appears like the one in the 3rd screenshot.

Click the Browse button and find the AXE027 folder that you unzipped from the driver download. In the screen capture, click on the axe027 folder and click OK.

If everything goes as planned, you should get a screen like the 4th screenshot tellign you the driver installed correctly.

Click the Close button and if you go back and look at the Device Manager screen, you should see that the device no longer has the little exclamation point next to it like my final screenshot here.

And that's it... for the driver install. Next, I'll install the Programming Editor software and get the circuit wired up.

Chapter 5 - Experiment 34 Software

2011-01-06T10:16:00.003-05:00

Before I get started with the circuit on page 299, I need to download and install the appropriate software and driver. The instructions for doing this are clearly explained on pages 296 and 297. I'm running Vista on my laptop, but be sure you click on the driver download that's appropriate for your operating system (Windows, Mac, and Unix all have links).

The 60MB Picaxe software is downloading right now, but when it's done, I'll first install the driver (while the USB cable is plugged in) and then the software.

Jumping to Experiment 34

2011-01-03T20:08:00.005-05:00

I spent a bit of time rewiring the entire circuit for Experiment 32... taking one of my readers suggestions that the protoboard could have a bad insertion area, I moved all the wires to new locations. I then replaced the 555 chip with a new one and used my multimeter to confirm that the relay was getting higher voltage on the coil when a microswitch was pressed. Finally, as a last ditch effort after these efforts produced no change in results, I swapped out the 47uF capacitor with a 100uF... increasing the size should have increased the length of the pulse, but in this case, I get the same results - the motor reverses only when the microswitch is held down.

Argh.

Okay... so... enough of this. I may choose to come back to it at a later time (things like this really bug me) but for now it's time to move forward and get this book finished. Which leads me up to my next announcement - I've read over Experiment 33 numerous times... lost count, actually. But I've decided I'm done with robots for right now. I understand what Experiment 33 does and how it works, and, more importantly, I understand how all those 555 chips work together.

So... now it's time to get to Experiment 34. I've been looking forward to this for a while as my interest in programmable chips has been growing ever since I saw an Arduino in action controlling a remote control lawn mower (see Make issue #22). But I want to start slow... so I placed the order for all the required hardware for Experiment 34 (and 35) and it all arrived this afternoon (see the picture).

I've got 3 of the 08M PICAXE chips, the special USB cable required, and the small stereo socket. Also included in the box was a handful of resistors and misc required to properly wire up the stereo socket. I need to download and install the software specified and I'm ready to go.

Note: Inside the box, the company also sent a photocopied sheet that included a hand-drawing of the 08M wired up in a special manner, complete with resistors and voltage requirements. I'm including a close-up of that photo here, but it doesn't look complicated at all.

More to come...

Chapter 5 - Exercise 32 Still Drivin' Me Crazy!

2011-01-01T17:08:00.002-05:00

This circuit is still driving me up the wall... I triple-checked all my connections, but I'm fairly certain the connections are done properly as the motor behaves somewhat correctly - it spins forward until a microswitch is pressed and then reverses direction... but only for a split second.

I used my logic probe to check the pulse on pin 3 but I'm honestly not 100% sure what I'm looking for...

One thing I did do that puzzles me - I unplugged the motor as it's quite loud and was making it difficult to hear the relay switching... when I did this and I turn on the power, I don't hear the relay doing anything, but when I press a microswitch, I hear the relay click (once) indicating that the coil is getting power and reversing the direction of the motor... but when I release the microswitch, I don't hear the click indicating the relay has switched back... but when I release the power button, I do hear a click. Maybe this is normal, but I'm wondering if somehow the relay is not functioning properly.

I've about decided to move on - I'll puzzle over it later tonight, maybe tomorrow... but if I can't find a solution, I'll move forward as I think I've gotten out of the experiment all I can.

Chapter 5 - Experiment 34 Shopping List

2010-12-30T15:37:00.003-05:00

Just an FYI - maybe save some of you some time...

I priced out the components for Exercise 34 on both Sparkfun.com and phanderson.com - summaries below. The advancedmicrocircuits.com website didn't seem to have the 3.5mm stereo socket (Figure 5-126) and their search feature just plain stinks... took me a few minutes to find the USB cable but had to search for 'picaxe usb' to locate it...

Total costs, with shipping are:

Sparkfun.com - $40.89 - this price is for 2x of the 08M chip, 1x of the USB cable, and 1x of the stereo socket adapter.

Phanderson.com - $38.35 - your price may differ as they use your zip code to estimate shipping costs... but this order comes with 3x of the 08m chip, 1x of USB cable, and 1x of stereo socket adapter.

I placed my order with phanderson.com today. I probably should have checked mouser.com and others, so if any readers do so, please share your findings - thanks!

Chapter 5 - Experiment 32 Do Over

2010-12-30T14:58:00.004-05:00

Well, I finally managed to grab some time to get back to the circuit on page 277... I bought a smaller breadboard that will allow me to mount to the robot (if I can ever get this thing working) and not have to solder every component... saving me some aggravation if debugging is required.

As you can see from the video, I've made a giant step forward - the motor spins forward until either of the switches is pressed... if the switch is held down, the motor reverses direction and continues reversing until the switch is released. But...

This isn't how it's supposed to work. When the robot hits a wall or table or other obstacle and a microswitch is pressed, the robot is supposed to reverse direction for about 5 seconds (more on that in a minute) and then move forward again... the wheel mounted to the moving pivot is supposed to help the robot find a different (random) direction to move.

Now, a few things that may or may not be affecting this circuit - first, I don't have a 0.01 uF capacitor for C2 in the circuit - I have a 0.1uF ... but I do have a 47uF cap for C1. If I understand the 555 chip correctly (referring back to page 157 for monostable mode) - a 47uF cap is on pin 6... and I've tried the 100K potentiometer at both settings (using a screwdriver to maximize and minimize the resistance) but no change.

I'm going to go back and take another look at my circuit, but I've double checked all of the circuits resistor values and all my wiring of the 555 and the relay. Because the motor is spinning forward UNTIL a microswitch is pressed, I think I'm close to getting this to work... but why it won't spin in reverse for the full 5 seconds still alludes me...

Chapter 5 - Exercise 32 Update 5

2010-10-20T15:09:00.003-04:00

Per Retrophile's suggested tip involving my relay being wired incorrectly, I changed the wiring and figured out my mistake (thanks Retrophile) - I assumed incorrectly that the relay's pins fit logically to the pin layout in the schematic... they don't. Going to the documentation for this particular relay verifies that Retrophile's pin layout is correct.

The two photos here show the rewired circuit - same circuit but just a slight change in photo angle for you to get a better look.

So, I've rewired the relay and as you can see in the first video below, the motor spins but the switches are still not causing the motor to stop and reverse. I used my multimeter to verify that I've got the switches wired correctly - the top and bottom pins are Normal Open (using the middle pin and bottom pin is Normal Closed and the multimeter shows a 1 when the button is NOT pressed... 0 when it is pressed). Per the schematic, we want the switches open, so I'm fairly sure I've got that wired correctly. I also replaced the 555 chip with a new one, just in case... but no luck.

So, my next step was to shoot another short video showing me using the logic probe on the 555 chip. My description here may not be 100% on the money, but as I understand the chip and the schematic, pushing a switch causes pin 2 to detect a drop in voltage... and causing pin 3 to allow current to flow (or is it just an increase in voltage - is voltage always present? Something to look into...)

As you can see from the video, putting the logic probe on pin 3 and pushing the power button causes the probe to change in pitch... that should be right. But then when I press any switch, pin 3 should change in voltage and be detected by the probe... but nothing happens. Any thoughts?

New Mouser.com web search tool

2010-10-08T08:11:00.006-04:00

I will say that, up to now, I have much preferred to use AllElectronics.com versus Mouser.com - mainly because I've found Mouser to be information overload.

This morning I received an email from Mouser.com about a new web browser add-on for both IE and Firefox called the Mouser Search Accelerator... it'll basically allow you to highlight a component - a word, a part #, name, etc, - and then, without leaving the page you're on, perform a search of Mouser.com. Pretty slick, and I think I'll give it a try soon. Let me know what you think if you give it a spin.

More information on it can be found here - it is something that must be downloaded and installed on your computer, btw.

UPDATE:

Okay, I installed it on my Firefox (3.6) browser - as you can see, after highlighting an old part # from a previous post, I right click and select to search on Mouser.com - a little fly-out window appears with links to the part and a price... and look at that! The price hasn't changed since I ordered the part back in April 2010.

Chapter 5 - Exercise 32 Debugging

2010-10-07T20:36:00.004-04:00

Suggestions are coming in on ways to test or fix the problems I'm encountering. Let me explain what's happening now.

I've inserted the diode that j suggested... works! The buzzing has disappeared (see video below). So we're getting close. Right now, pushing either switch (that will serve the robot as a trigger to stop and back away from an obstacle) does not stop the motor from spinning - pushing either button is SUPPOSED to cause a drop in voltage on pin 2, so I think my next step is to use a chip tester to see if pin 2 is being triggered. (Right? No?)

I'm including some pictures here - one is the schematic and the rest are close-up photos of my circuit - maybe I've got an unseen error in my wiring. Be warned - my use of the breadboard is obviously that of a newbie, so I've got wires running all over the place. If I can't figure this out soon, I think I'll start over and try to rewire a bit cleaner and closer to the layout of the schematic.

Thanks in advance for all your comments and suggestions - I love learning by doing... and making mistakes is another favorite technique of mine as I tend to remember what I did wrong versus what I did right... and that's what drew me to this book in the first place!

First video below is WITHOUT the diode.

Second video is WITH the diode.

(FYI - family visiting this weekend so I may not get much more work done on this circuit until early next week.)

Chapter 5 - Exercise 32 Update 4

2010-10-07T16:14:00.003-04:00

A short update today - only a small bit of progress... let me explain.

First off, I've gotten over sharing my dumb mistakes with the world via this blog... when you decide to walk through a book and perform all the tasks/exercises/experiments and share your results, you've gotta expect to have the occasional embarassing moment. I've had plenty during my tour of Make: Electronics, and I'm not done yet...

So, here's what happened - take a look at the schematic for Experiment 32 (if you have the book)... see that 50K trimmer there and how the left side of the resistor isn't connected anywhere? That's not an error... but I thought it was! So, I just connected that end where it felt right.

And... of course... the video yesterday shows my results. So, after Mr. Platt explained this little techy bit to me, I pulled that wire and ran the circuit. The motor still spins, but THIS TIME the two microswitches, when pressed, stop the motor. Progress. But not fixed.

Pressing either of the microswitches is supposed to reverse the motor's spinning for a short period of time. But it doesn't. Instead, pressing a microswitch causes the relay to buzz LOUDLY and the motor does stop rotating... almost. If you hold down the microswitch, the motor appears to stop but in reality it still rotates in the original direction but VERY slowly... almost impossible to see. Oh, and the relay buzzes LOUDLY! Release the microswitch and the motor begins rotating in the original direction again.

So, don't connect the 50k trimmer on both ends... just the one shown in the figure. And if anyone has any ideas WHY my relay is buzzing AND why either microswitch doesn't cause a reversal in the motor spin, please let me know... I'm taking a step back to think about this for a bit.

Components Pack 1 Frustrations

2010-10-06T13:03:00.003-04:00

I just went over to the Components Pack 1 webpage to confirm the list of components in the kit... and I was surprised to find a large number of negative reviews... after reading over them, it appears that the kit has been out of stock for just over a month (earliest 1 star review was August 21... latest Oct 1).

I'm not sure what's happening, but if you're trying to gather up the parts on your own, I've tried to include my Shopping Lists in previous posts, including part#s and sources. I may have missed a few, but hopefully there's enough information there to help you consolidate some shipping from multiple sources. (Click on the Shopping List label to the right of the screen to filter the blog and display my shopping list articles... if I've missed one, please let me know.)

I know it's frustrating - I was already well into Chapter 4 when these kits became available and it would have been nice to have all these parts together in 2 kits. But hang in there - if you've got the book and are wanting to get into it, keep in mind that the Chapter 1 exercises are low-cost, really... I'm not counting the tools such as the breadboard, soldering iron, etc... I'm talking about the components like LEDs, batteries, a few capacitors, resistors... you can easily get deep into Chapter 1 before spending a lot of money and in that time, maybe Components Pack 1 will become available. (It looks like Pack 2 is still available.)

Chapter 5 - Exercise 32 Update 3

2010-10-06T11:01:00.004-04:00

Before cutting out the wood for the shell of the robot, I figured it might be wise to actually wire up the schematic first and see if I can get all the electronics to work. As you can see from the video and picture, I've managed to wire up the motor - I've got a temporary push button that allows me to provide power to the circuit. I'll get an actual on-off switch once I get the circuit de-bugged.

The circuit is definitely providing power (6V) to the motor, but the two microswitches are not working as desired. When one is pressed, it's supposed to drop the voltage on pin 2, triggering the coil and reversing the spin on the motor... but that's not happening. Pressing either switch does not reverse the motor. I'm using different microswitches than the ones seen in the chapter, but I don't think that's the issue.

I also need to get out my chip tester and make sure that voltage is detected on pin 3 that runs to the coil.

Obviously, any suggestions my readers may have will be appreciated.

Chapter 5 - Exercise 32 Update 2

2010-09-27T15:55:00.003-04:00

My motor, wheel mount, and other bits arrived today. As with most electronics ordered, there's no paperwork on any of it. I can figure out most of it, but the motor has two unlabeled soldering points... my guess is that it DOES matter which wire goes where as the motor needs to spin in one direction specifically... so... I'll need to revisit the Solarbotics website shortly and see if they have any documentation. Otherwise, The Internets will need to deliver!

I'm going to mark out the cuts tonight for the wood pieces that will make the shell. Not going for accuracy here, so I'll likely just use a handsaw and not flip the old tablesaw on for such small (and thin) plywood.

More to come...

Chapter 5 - Exercise 32 Update

2010-09-22T15:52:00.003-04:00

My box of parts has shipped from Solarbotics, so it's just a waiting game now for the motor and other bits. I was ready to cut the 1/4" plywood but decided to wait until I get the motor and determine that it can actually be mounted properly, including the hole I'll have to drill for it to drive a wheel.

In the meantime, I took a look ahead to the next robot that will require two photoresistors and two servos. I didn't find what I needed at Solarbotics, so I'm going to keep looking. One thing I'm finding is that servos on a lot of electronics websites come with almost no documentation or so much that you can't make sense of it. For those of you who have not yet started in on Chapter 5, just be warned that there's a fair bit of hunting involved - many of the key parts don't come in either Make: Electronics component kit 1 or 2... makes me think Make might want to consider a final kit titled "Chapter 5: The Missing Bits."

Chapter 5 - Exercise 31 Final

2010-09-19T17:50:00.003-04:00

So, it was a very nice afternoon today (a bit hot, though) in Atlanta - sunny sky, no clouds, no rain. I had a 3 year old helper who was very curious about all the wire and odd bits sitting on the deck table. After running some unshielded copper wire almost 80 feet and tying it off with the recommended polyrope to a tree, I wired up the remaining circuit as shown on page 265 in Figure 5-66.

With high hopes, I inserted my earphone and moved the gator clip down the wrapped bottle, trying each tap.

No luck.

So... I began troubleshooting. First, checked and then double-checked all my gator clip connections. They were good - and every time I clicked on a tap, I'd hear a slight electrical snap in the earphone... kinda like the crackle of static on a radio. Checked each tap again... nothing.

Next I replaced the Germanium diode... I purchased a bunch so I swapped it out two more times, checking the taps. No luck, other than the crackle in the earphone again.

At one point... maybe it was wishful thinking... I honestly think I heard something. Very faint... there just for a second and then gone. I played with various taps and checked all my connections again, but just had no luck picking up anything.

Still... I had fun. And I understand the theory and what SHOULD have happened and WHY. I wish I'd had luck, but I honestly don't even know where the nearest AM broadcast is coming from... living in Atlanta, I've just assumed I'd pick up something!

If any readers perform Exercise 31 and have luck, PLEASE let me know! I'd love to be able to share some pictures or video or even a recording of any transmission you hear with your project.

Up next... I'm going to cut up the parts this week for the robot in Exercise 32... today I managed to swing into the local hardware store and picked up the following:

1 piece of 2x4 1/4" Sandiply (sanded really smooth on both sides) $7.98
1 package of 2" utility hinges (3 per package) - $2.21
1 package 3" diameter felt circles (for under the feet of furniture) - $3.78

Yeah, I know... felt circles? Well, they're 3" in diameter with no center hole drilled and they are very stiff and 1/4" thick. Perfect for the wheels (and, hey... they won't scratch my floor! Bonus!)

Update and Exp32 Shopping List (Partial)

2010-09-18T20:19:00.002-04:00

I'm hoping for some good weather tomorrow (weather.com says YES) so I can head outside and put the finishing touches on Exercise 31... try out my little radio and see if I can pick up any of the AM band radio stations around Atlanta. I hope so... would be a nice surprise.

In preparation for the upcoming Experiment 32 - you know the one if you've been looking ahead in the book like I did! - building the Little Robot Cart. After placing a few phone calls to a few places in Atlanta, I basically decided that with the $6.00 shipping that solarbotics.com charges, I'll end up saving some money if I just wait a week or so for the following components:

1. DC Gear motor
2. Disc for motor
3. Two SPDT microswitches
4. 1 DPDT nonlatching relay

In the meantime, tomorrow I'll also be heading up to my hardware store to buy some 1/4" hobby plywood. Yes, I know... the author recommends ABS plastic. But right now I'm not wanting to invest in a plastic bender and I'm comfortable working with wood and have the right tools to cut the proper pieces (see on page 275). Not sure about the wheels, but I'm fairly certain I can find some thin wood wheels at a Michael's or Hobby Lobby that will fit the bill. Otherwise, I'll invest in a 3" bore hole bit and cut my own. I may attach everything with screws or I may go ugly and just stick everything together with superglue or Gorilla glue... not really going for something to enter in a science fair, so not concerned about looks.

If anyone finds these components elsewhere (and cheaper), please share with your fellow readers... in the meantime, I'm posting a screen capture here of the part #s and prices (and quantities) for Solarbotics.com.

Kinda glad to have found some time to get back to the book - I apologize to my readers for such a lengthy delay in finishing up the exercises. Now let's finish this book!

One Day Digital Book Sale

2010-08-11T08:16:00.002-04:00

O'Reilly has a great deal right now on some eBooks - for $9.99 you can get any of their Top 10 books and guess which book is on that list?

That's right - Make: Electronics is available in digital format for only $10 (no shipping costs!) - if you've been considering purchasing a digital copy or know someone who's shown an interest in the book, this is a good price.

I have the digital version on my iPad... I wish I could say that I've been referencing it a lot lately, but a certain 2 month old baby boy has been stealing MUCH of my attention. I keep promising to return and get back to work on the book and I am going to do my best to get back to it this week as I've got some downtime that's finally rolled around.

Anyway - this is a ONE DAY deal, so strike now: http://oreilly.com/store/ddbst.html

Update on Blog

2010-06-24T17:31:00.002-04:00

Sorry, all, for the big delays in posting. My wife delivered a 10lb, 7oz baby boy on June 14th... and the weeks before were a bit crazy as well as the last week and a half.

Baby and momma are fine, life is somewhat returning to normal, and I'm ready to get back to the blog and finish my coverage of the experiments in the book.

I'll try to have a conclusion/summary of Experiment 31 before Saturday... and I've been collecting my notes on Experiment 32 which appears to be one of the larger and more time-consuming exercises. I've been looking forward to that experiment ever since I first skimmed the book, so it's nice to have reached that point... now if I can just find some spare time to cut out the pieces.

Excuses, excuses... thanks for your patience, and I'll get back to work on the blog and book shortly.

Chapter 5 - Exercise 31

2010-06-02T12:38:00.003-04:00

So we're going to build an AM radio with an empty bottle, lots of wire, a germanium diode, and a cheap earphone... sounds fun.

A few things - I didn't have a 3" diameter bottle, but a 2.5" Flinstone's Vitamins bottle, generously donated by my 3 year old son who allowed me to put the remaining vitamins in ziploc bag. Thanks, D!

After removing the label and cleaning the bottle, I drilled the holes as instructed. It's hard to tell from Figure 5-60 how tall that bottle is but I don't think my bottle is tall enough to hold the 12 "taps" that the instructions say to build... and because the bottle's diameter is less than 3", I multiplied by the 16 to get a 40" distance between taps. Doing a little math, I quickly figured out that 12 taps wasn't going to wrap around once I got started...

BTW, start at the bottom of the bottle and work your way up - it's easier to tie off the wire when you're done wrapping if the holes near the top are exposed - I managed to get my fingers through the bottle opening and get it tied off. The author recommends 22 gauge wire, solid core... I used insulated and I'm glad I did... makes it much easier to wrap and you'll save your fingers from wire-burn... yes, I made that term up, but exposed wire does get hot to your fingers when you're wrapping... your call.

After wrapping my bottle tightly, I managed to get 10 taps before running out of room... I don't think this will be an issue but may give me fewer chances of success when it comes to picking up a signal. As you can see, my taps aren't spaced as far apart as the author's are in Figure 5-64... crossing my fingers and hoping.

Up next, getting the antennae setup... I've got the germanium diode and earphone, so I need to get some rope that won't interfere with the antenane and keep it from grounding... more to come.

Special Project

2010-05-27T13:13:00.004-04:00

To quote Chris Knight - "It's yet another in a long series of diversions in an attempt to avoid responsibility."

Rather than pull my hair out (because I kinda like having it) I'm taking a very short break from the book to try my hand at an electronics project that is easy to follow and understand from what I've learned from Make: Electronics... here's the story:

My 3 year old son has discovered... MONSTERS! We've tried to assure him they're not under the bed or in the closet, but he has these moments where he's certain they're around the corner... we've tried to assure them there's no such thing... but he's 3! He probably DOES see them with that imagination of his... so...

I've decided to empower him. No longer will monsters be allowed in our house! As long as he has his trusty Monster-B-Gone with him, all is well.

The Monster-B-Gone is my simple little project involving 6 LEDs moving like the traditional cylon or KITT the super car. Back and forth... back and forth. With the push of a button, my son can banish monsters because, as we all know... monsters HATE the color green! One push of the button and they're off and running! I've already started talking to him about the hows and whys of the animosity between monsters and the color green. I think he's buying it... this should work for a bit and give me time to work on the next solution.

I've based my circuit on the Cylon Pumpkin... if you want to build the same circuit, I've consolidated the author's circuit drawings into a single PDF file you can download here. As you can see from the video, it works fine. I'll be transferring everything to a small project box with a momentary button on the top or side so the batteries aren't being constantly drained. More later as I get the soldering moving forward...

I promise I'm NOT done with the book or the projects... just need to think about something other than Experiment 29 for now...

Chapter 5 - Exercise 29 Update

2010-05-24T16:03:00.002-04:00

Well, I don't know... I've tried quite a few things. First, I replaced the wire to the speaker with a high gauge wire (thinner and twisted, not solid core) because I was worried maybe not enough power was being generated. No luck. I also replaced the TEA chip and a few capacitors (didn't have enough of each size to replace them all) but that doesn't seem to have helped either.

Next, I took a look at the adapter. I thought - okay, maybe the adapter just isn't functioning... but no, it works. I used it with some patch cords to connect to a small radio with the right plugs and my iPod played music just fine. So something is wrong with my circuit.

Based on past experiences with this book's exercises, I knew it had to be operator error. Something small and simple to overlook... but I checked all my resistor values, checked where every wire was going (positive or negative voltage), double and triple checked ever TEA chip pin to make sure they were all wired properly and none were ignored... and I'm getting zip.

Is it possible that the iPod via the adapter via the breadboard just cannot power this 8" speaker? Suggestions welcome, but I'm probably going to go ahead and ship to exercise 31 and leave this one alone... I don't have to take it apart for exercise 31, so I'll give it a break and see if a light appears in the sky with the answer.

Argh.

Chapter 5 - Exercise 29 part 3

2010-05-19T09:44:00.002-04:00

Okay, I'm still having trouble with experiment 29. I'm including some close-up photos here, hoping that someone may catch an error or see something that I'm not doing properly.

A few things - the schematic on page 251 (Figure 5-41) shows the hookup wire and the 10 microfarad components wired up in series but with a set of pushbuttons used to isolate them. I thought this might be the issue early on so you'll see that I've only got the hookup wire in the circuit... I figure if I can get the sound working with the hookup wire, then I'll pull it out and insert the capacitor.

Other than that, I believe I've wired up the circuit as seen in Fig 5-41. I've verified all my capacitors and resistors for their values... the TEA2025B chip is inserted with the proper orientation... and I've got the 100 microfarad smoothing capacitor between the voltage inputs. The headphone jack is the only other questionable issue that I'm not sure how to test... I taped the wire inserted into the one socket as well as the one connected to the outer metal surface of the other socket...

One question, though - I used solid core 22 gauge wire for the speaker. I'm wondering if that wire is too "heavy" for this experiment.

Any advice is welcome... I'm not wanting to get bogged down on this experiment but experiment 30 builds on it... so if I can't get it working soon, I'll have to skip 30 and jump to experiment 31. If anyone has successfully completed this experiment with solid results, please let me know, as well. If I can't get it working, I'd at least like to get a video of an actual working project.

Chapter 5 - Exercise 29 part 2

2010-05-14T09:37:00.004-04:00

I got everything hooked up and I double-checked the schematic for all the resistors, capacitors, and pins on the chip. I chose to use my iPod with the $5.99 adapter I purchased from Radio Shack.

I also got the speaker built - it's ugly as it can be but it's bolted to the plastic box and yes... those are Mickey Mouse diapers in the bottom. We use what we can... my son is in pull-ups now, so I don't think he'll mind.

I decided to video the first power up... you can see that below.

Chapter 5 - Exercise 29

2010-05-13T09:57:00.003-04:00

Apologies for delays in posting recently - throw in a small bit of procrastination with my mistakes in ordering incorrect components and ... you get the picture.

I got most of the schematic on page 251 wired up - it's a variety of colors, isn't it? I do believe there are a couple of mistakes here, but I'm not going to post them to the errata page until I get confirmation from a reader or from the author.

On page 251, for example, the 100microfarad smoothing capacitor for the 9V has the symbol of a nonpolarized capacitor, but the text says to use a regular electrolytic. I'm going with the text because of the author's explanation for WHY to use that type of capacitor...

Also, the 0.15microfarad capacitors are shown as NP type but not labeled as such... here, I'm going with the NP variety (that's all I have anyway) because of the symbol. Also, please note that that 0.15microfarad capacitors are not specified in the shopping list... I don't have any from previous experiments in the book, so I had to grab some of these locally.

I shot the photographs here before writing this up, so I also just noticed a mistake I made - the NP capacitor sharing the top part of the circuit with the coil is a 10 microfarad, not 100 as I've put in my circuit... fortunately, I haven't powered mine up yet... more on that in a moment.

I'm also wanting confirmation on something in the schematic - the 100microf coming out of pin 6 goes into pin 1... not connected to negative voltage as the other two 100 microf on pins 8 and 11. These are HUGE capacitors, and I'm very nervous about powering up this thing until I get that resolved as well... my initial thought was that that capacitor on pin 6 should at least have a connection to negative voltage, but maybe pin 1 is initially negative (a sink?)... again, not sure so I'm not powering up this bad boy just yet...

I've also got to pick up a headphone socket like the one in Figure 5-42 as well as some hardware to mount my 5" speaker to the plastic box. Will do that today.

We hear so much about audio and video equipment and the high voltages and currents they use/produce... so I hope you can understand my nervousness about plugging this breadboard in until I have all of these details ironed out... don't want a burned breadboard or any exploding capacitors in my vicinity... even with eyeshields on.

Experiments 29 and 30

2010-05-10T14:15:00.002-04:00

Experiment 30 builds on Experiment 29 - unfortunately, I've had some bad luck getting the proper components for these 2 exercises. Exp 29 calls for 100 microfarad capacitors of the nonpolarized electrolytic type... ditto for 47 microfarad. I thought I'd ordered the proper BP type capacitors... apparently not.

One thing I did notice about Experiment 29 was that it calls for two 47 microfarad capacitors but they're not seen in the actual schematic on page 251. I do see in the schematic two 0.15 microfarad capacitors... I don't have those either... added to the shopping list. You'll also see a 10 microfarad NP capacitor that's not listed in the experiment's shopping list... argh.

I've called ACK supply and I believe I can get the right components this week, but I'm not driving to that part of town until Wednesday... so Exp 29 and 30 are on hold temporarily. (In the meantime, I've read over Experiment 31 and believe I can go ahead with that one while trying to get the capacitors.)

I'll also need to pick up the headphone socket seen in Figure 5-42 - this isn't on the shopping list either. Thankfully, I purchased one of those big bags of resistors so I've got those covered, including the TEA2025B chip required. Again, sorry for delays, but I'll get back to these two experiments soon.

On to Experiment 31...

Chapter 5 - Shopping List Update

2010-04-30T13:10:00.003-04:00

Got a few more items in for Chapter 5 from various sources.

First, I purchased 10 germanium diodes and a single piezoelectric earphone from SciToys as the author recommended. Since I was paying for shipping, I ordered 10 diodes instead of just 1... I may never use them but they're not that expensive and I know a few people (including my dad) who are working through the book and I may part with a couple.

I couldn't believe I couldn't find these items locally - no Radio Shack that I called carried either the germanium diodes or the earphone and the few electronics shops I called carried the earphone but it was $10.00 and no germanium diodes.

Note: These items are NOT included in the Components Pack 2 - as a matter of fact, I'm finding quite a few things in the final experiments in Chapter 5 that are not included with Pack 2. (This isn't an error - Pack 2 states it is specifically for Chapters 3 and 4.) I'm trying to capture all the specialty items required for Chapter 5 and will see about making one final Chapter 5 shopping list that contains those items NOT found in Pack 1 or Pack 2. For example, Experiment 28 recommends a 4700 microfarad capacitor but the shopping list specifies 2000 microfarad minimum... if you're like me, you probably don't have any of these in your possession. Again, I'll try and go through Chapter 5 when done and pull together a complete list of specialty items.

Also, I picked up a plastic box for $1.50 at The Container Store... I was in the neighborhood and remembered that I needed one for Experiment 29.

From SciToys (www.scitoys.com)
10DIODES $7.86
EARPHONE $6.84

(Those are the actual part numbers above with the prices.)

Chapter 5 - Exercise 28

2010-04-30T12:44:00.004-04:00

I'd never seen this application of a coil, but the theory you'll read about for Experiment 28 makes sense.

In the first part of the exercise, I simply wired up the circuit on page 247 and pressed the button. As expected, a single LED lit up on the button press and the other LED lit up on release of the button. It happens quickly. The author recommends against holding down the button because the resistor will get hot fast. You can see this in action in the first video.

The second part of the exercise involves hooking up a capacitor in place of the 220 ohm resistor (don't forget to add in the single 1K resistor). The author states that capacitance works the opposite of self-inductance, so you would think that based on the first exercise, we should see the 2nd LED (on the right in the video) light up first, and then the 1st LED (on the left) after the button is released. The second video shows my results.

What happened? As I understand it, capacitance resists at first and wants to take most of the current to charge up - so the first LED does light up, but not as bright. Releasing the button causes the capacitor to discharge and I can only guess that the resistance in the coil is very low (compared to LED 1) so the current flows through the coil and then through LED 2. Of course, I could be completely wrong as I expected LED 2 to light up first... then LED 1. Goes to show that electronics don't always behave in the ways we expect them to... (or maybe I wired up this modification incorrectly - if anyone knows, please let me know so I can try again.)

A fun experiment... just be sure to wire up that capacitor correctly (for polarity).

Finally, I got my copy of 'Practical Electronics for Inventors' by Paul Scherz. A quick scan of the entire book and a read of the first few pages tells me that although the material is quite dry (compared to Make: Electronics), it should be very useful. I can already tell that this book should be easier to read and understand after having completed Make: Electronics.

ePub digital edition - Update

2010-04-28T19:40:00.003-04:00

Thanks go to Seth over at O'Reilly Media, Inc for emailing me an updated version of the book - as you can see, the cover looks great on my iBook shelf.

Chapter 5 - Exercise 27

2010-04-26T15:50:00.005-04:00

Exercise 27 calls for you to destroy a small 2" speaker... the way these speakers are designed, I don't think you'll be repairing it after you've made the required cuts to tear it apart and see how it works. I've taken video of the process if you'd rather not destroy your own speaker.

The coil of wire wrapped around the small cardboard tube is surprising. It's very fine and wrapped nice and tight, obviously by a machine. If I understand my reading of Exercise 27, the electric current sent to the speaker will create a magnetic field in the coil that will fluctuate... these fluctuations will cause the magnet to move up and down, with the air waves created moving the black paper cover that I cut away from the speaker. The paper cover's movement is what creates the sound waves that the listener hears.

A very simple device... only two moving parts as far as I can tell - the magnet and the paper cover. Amazing.

Chapter 5 - Exercise 26

2010-04-23T15:27:00.004-04:00

This was another fun little exercise that I've seen in various forms over the years... the picture on page 241 (Figure 5-22) really does hammer the concept home - given the right components, you could create something to generate a sufficient amount of voltage to power a lightbulb or other low power device. Of course, I'm not sure where you'd find a magnet of sufficient size to make this experiment bigger (or safer) but the theory does make sense.

A few notes...

I wish I'd purchased a slightly wider diameter magnet than 3/4" - the hole in the center of my magnet wire spool is a little over 1" in diameter... a 1"diameter magnet would have been perfect. The 3/4" I had worked, but it bumped the spool and wasn't as easy to move up and down as a magnet that was a tighter fit.

Also, don't forget to sand off the ends of the magnet wire - I forgot about the little bit of clear insulation over the wires and didn't get any results at first. You can see in the first video that I eventually do get the red LED to light up. (FYI: I connected another LED in the string and got both to light up at about half the number of blinks as a single LED... adding a third LED resulted in zero light.)

Next, I connected the 100microfarad capacitor as seen in Figure 5-23, with the diode properly oriented. The second video shows that I got up around 2.6 volts... a nice number! I didn't get close to the 10V the author mentions, but there are so many factors at play here that I'm sure I could have reached it with the right diameter magnet and spool hole.

As the author advises, be careful with these magnets. Fortunately my titanium ring that I forgot to take off wasn't attracted to the magnet. Of course, I didn't keep the extra LEDs and gator clips far enough away and was always having to pull them off. I finally got smart and started storing the magnet in a small plastic container by itself until needed.

Make: Electronics - ePub version

2010-04-23T10:17:00.003-04:00

My printed copy of the book is getting... worn. While sharing it last week with folks at WorldFest, it got handled by kids, adults, and adults who acted like kids. Most of the damage to the book is mine, especially the writing and highlighting in the chapters, but the book is definitely showing wear and tear...

I've been wanting to get a digital copy for my iPad... and what do you know? O'Reilly is offering a special on eBooks (up to April 30) where you buy 1, get 1 free. Buy 2... get 2 free, etc. One thing I like about their offer is that for most of their books they offer them in multiple formats - PDF, ePub, and Kindle. And another nice point is that they don't have DRM... no annoying password to type in every time you want to read your book. So, I purchased the digital version (ePub) of Make: Electronics and imported it into my iPad. (My free 2nd selection was Head First Statistics - same price, so it was like getting both eBooks half off - I like the topic of statistics and wish I was better at it... this book impressed me in printed form, so there you go...)

Here are some screen grabs from the iPad. I can shrink or enlarge the text as needed, so the page count doesn't match the printed book since I've enlarged the print just a bit. All in all, it's quite nice thumbing through the pages of the digital version. My only complaint? Take a look at the iBook shelf and you'll see that the cover of the book simply says "Make" and has the author's name. Come on, O'Reilly! How hard will it be to modify the ePub file to display the actual cover of the book? Look - my Apress book "LEGO MINDSTORMS NXT: The Mayan Adventure" has its cover... it just looks so much better (my publisher sent me a copy to see how the ePub conversion worked and looked on the iPad - this author is VERY happy with the results). Maybe someone will fix that.

Another nice thing I want to add - by purchasing the digital versions, I get free updates if the books are updated/revised... that'll be nice when the errors found in the book are fixed in a future revision.

Chapter 5 - Exercise 25

2010-04-22T15:32:00.003-04:00

As the author says, this is an experiment I've seen done numerous times in the past... but never done myself. I remember my high school physics instructor doing something like this but with much more wire... still, 6' of wire did have an effect.

Also, the author points out that stranded wire doesn't give you the same results as solid core... I used some duct tape to secure my coils as I built each level and then wrapped the entire thing in a blanket of tape as you can see in the pictures and video.

The magnetism wasn't strong, but it was there... and noticeable. While doing this, I had a strange recall of something else I learned way back when... if you take your right hand and make the hitchhiking gesture, notice the direction of your thumb and the direction of the curl of your fingers... if the current is flowing in the direction the thumb is pointing, the magnetic field curves in the direction of the fingers. I'm trying to get my mind around how this can help me with this experiment... maybe it's not relevant. Who knows...?

So, Experiment 25 - fast and easy. Just give yourself some time to wind that wire... and trust me, holding a 1.5v battery to the ends of the wire won't shock you... but it heats up FAST! I wore a glove the second time around... I could have used alligator clips, but this was more fun...

Sorry for the lack of sound - got a new camera and for some reason I couldn't get the sound to work when I downloaded it to my video editing software - definitely need to read that manual!

UPDATE: Figured out my issue with my new camera - sound is working now on the video below.

Chapter 5 - Shopping List Update

2010-04-22T14:42:00.004-04:00

I used to look forward to the occasional Amazon box that would show up on my doorstep. Not anymore... now it's boxes from Mouser or AllElectronics.

In addition to much of the stuff specified in Chapter 5, I also managed to squeeze in some extra components that I've been wanting to add to my collection. As you can see from one of the photos, I took this chance to throw in an order for a bunch of capacitors of various values. Some are used in the book, others are not, but I've learned that you can never have enough of them and the one you need will always be missing when you need it the most.

The two brown containers in the right side of the photo contain the speakers used in various experiments in Chapter 5... the rest of the stuff is described below. Note that I did NOT buy everything yet for Chapter 5. A couple of the later experiments call for some more components that I'll likely purchase locally when I need them. Those large purple things are capacitors... BIG capacitors. They look scary... and fun.

So, here's a partial list, with prices and part #s:

Mouser.com

NTE110A General Purpose Diode, Germanium - $1.57 each - purchased 2 (Exp 31)
2N2222 General Purpose Bipolar Transistors - $1.09 each - purchased 2 (Exp 30)
TEA2025B Stereo Audio Amp - $0.68 each - purchased 2 (Exp 29)

(That last one, TEA2025B, I could only find on Mouser.com - AllElectronics didn't seem to have any alternative to it - if anyone finds an alternate source, let me know.)

AllElectronics.com

26YL-100 Yellow Hookup Wire, 26AWG, 100' - $4.30 - purchased 1 roll
MW-26-4 Magnet Wire, 26AWG, 1/4LB roll - $6.58 - purchased 1 roll
SK-63 63Ohm speaker, 2.25" - $1.25 each - purchased 1 (Exp 27)
GM-858 Midrange Driver 60W speaker, 8ohm, 5.25" - $8.70 each - purchased 1 (Exp 29)
100R50 Capacitor, 100microfarad/50V, $0.30 each - purchased 2 (Exp 26)
2200R50 Capacitor, 2200microfarad/50V, $1.25 each, purchased 2 (Exp 28)
ATP-100K potentiometer, 100K, $0.75 each, purchased 1 (Exp 30)

Chapter 5 - Work Area and Misc

2010-04-20T22:58:00.001-04:00

While I wait for my final shipment of parts to arrive for Chapter 5, I've read over the first part of the chapter covering the work area and reference material.

For a while I was working on my dining room table... certain looks from the wife made me realize that my upstairs office might be a better location. Luckily I had a second desk up there that I was able to clear off and use for a bit... but my ultimate goal has been to get my electronics stuff moved to a dedicated spot in my basement workshop. I've got a very good spot for a desk, and there's a nice power outlet right there for me to use to hookup a power strip for more plugs.

I've been collecting small plastic boxes for all my components... but I've also discovered that I'm building up my component collection faster than my storage boxes. Fortunately the author makes some good recommendations and I'll be paying a visit to Michael's or Hobby Lobby soon to see what they have to offer. Ideally I'd like to buy the color coded boxes - one color for resistors, one for capacitors, etc... right now my boxes are compartmentalized but might contain one bin of capacitors, one bin of potentiometers, another bin of gator clips... you get the picture. (My resistors are the only components I have that are organized properly in their own boxes.)

I've been on the lookout at Craigslist.com for The Desk. You know - the perfect desk. Low price (free would be great). Not too beat up. Drawers that work. Plenty of desk space. So far, nothing meets my requirements. I'll keep looking.

As for reference books - "Practical Electronics for Inventors" ... I had another electronics expert tell me that it's a great book to own in addition to the author's recommendation - so based on these two recommendations I grabbed a used copy for $26.00.

I already owned a copy of "Getting Started with Arduino" - personally, I found it too simplistic and skimpy for the price.

I also have had a copy of "Getting Started in Electronics" by Forrest M. Mims III - great book but still didn't get as much from it as I got from Make: Electronics. Everyone raves about this book (and his Notebook series) but I view them more as reference because I just didn't get much of an education from reading it straight through... maybe your mileage will vary.

And while I'm here, I have to thank my good friend Chris Smith (a fellow LEGO Mindstorms NXT robot enthusiast) for introducing me to Fritzing. If you are already familiar with it and using it, then you know how cool it is - but if you're not experienced with it, check it out... totally free and I can already tell it'll be a great tool for helping me document future breadboard work. Chris also pointed me to Drawdio - yet another project to add to my TO DO list... but 100% doable after having gone through Make: Electronics. This one should be a piece of cake.

My AllElectronics order is supposed to arrive tomorrow. I'm really looking forward to this chapter's experiments.

Chapter 5 - Shopping List

2010-04-14T12:09:00.002-04:00

I've begun ordering some of the components for chapter 5... but not all. I'll try and get a detailed list (with part #s and prices) posted soon, but I did want to alert readers to the fact that I'm having some real difficulty locating a few items.

For Experiment 26, I ordered the wire (both hookup and magnetic) from AllElectronics - only because I was planning on ordering more small pieces from them and figured since I was paying for shipping, I might as well bulk up that order...

The magnets have been ordered for Exp26, too - a little pricey but I've always wanted some strong magnets anyway, so I ordered 3/4, 1/2, and 1/4" diameters, all in 1.5" lengths.

The TEA2025B audio amplifier IC for Exp29 stumped me - couldn't find an equivalent at AllElectronics and ACK Supply (my local supplier) doesn't carry them. So I ordered 2 of them from Mouser.com along with a small collection of capacitors, both polarized and nonpolarized based on the Exp29 requirements.d

None of my suppliers carry the Crossover Coil (see Figure 5-45 on pagee 253)- the author does state these are tricky to find and eBay did have 2 of them for $13.00 plus shipping. I read over the writeup there... I'll continue to try and find some inexpensive ones, but if not, I may skip that part of the experiment or substitute the coil wire as the author suggests... (but I get the impression that it won't work very well without the actual crossover coils...)

Chapter 4 - Experiment 24 Overview

2010-04-14T10:20:00.005-04:00

I never got my Alarm System to work quite right back in Chapter 3... after re-checking the circuit board (this one was soldered, so any errors I made will be difficult to fix) I I still can't figure out why it doesn't work properly.

Experiment 24 is all about upgrades to that device. The author suggests using a 555 Timer chip to give a delay after you set the alarm (time to get out of the house)... as well as adding the keypad to activate and deactivate it with a code. Another 555 chip is suggested to add a delay before deactivation (to allow you to enter house and enter code before alarm goes off).

All three are great upgrades, but I've decided to move forward to Chapter 5 rather than go back and try to fix my Alarm System so these upgrades might (or might not) work. My intention with this blog was to perform all the experiments, but on this one I've read the text and understand what the upgrades will do... I may choose to come back and revisit this exercise when I'm done with the book...

I'd still like to see a fully functional alarm system with all these upgrades... so while I ponder doing it myself, I'll create a new contest here. I've got 2 more Maker's Notebooks as prizes. The first two readers who submit a video and a few photos of their upgraded Alarm System that works based on the Experiment 24 writeup will each get a copy. So, if you're working on the Alarm System now, set it aside when done and come back to it for Experiment 24 - you may win a Maker's Notebook if you succeed in getting it to work.

I'll be attending the WorldFest International Robotics Competition this week, so I'll start up with Chapter 5 this weekend. I've been looking forward to this chapter - it's got some very interesting projects to build.

Multimeter - one day deal

2010-04-14T08:19:00.002-04:00

Just for today - a nice price on a good multimeter - I'll remove this post when the item is sold out.

http://auto.tooliday.com/

Components Pack 2

2010-04-13T15:51:00.004-04:00

I received my Components Pack 2 today... very well done. I can't believe I'm seeing all those hard to find (or at least, slow to find and receive) parts in one place... especially the 5V regulators of which Radio Shack doesn't seem to carry more than 1 at a time. Grrr.

Anyway... rather than go through the pack, I took some video and threw together this little 8-minute overview. Questions about it? Just let me know. I'll be taking it with me (along with the book) to the WorldFest International Robotics Competition being held in Atlanta this week, Wed to Sat... if you're in Atlanta, come by the LEGO booth and say hello.

Chapter 24 - Exercise 23 Complete

2010-04-12T15:06:00.004-04:00

The photos here show the circuit on page 219 (Figure 4-109). I'm not sure if I'll go forward with the enhancement described on page 220... I understand what it does and how it works, but wiring up this one took a bit of time (and mega-patience) and I'm a bit ready to move forward.

I managed to purchase 10 of the 1N4148 diodes from Radio Shack - they ordered them and it cost me $1.49 for a pack of 10... and took about 10 days to get here... boo. (I was told 2-3 days... another valuable lesson learned... of course, I didn't have to pay for shipping which would have been more than the 10-pack!)

As you can from the video, the circuit works. I like when you hold and release the button -the visual effect is fun to watch. I may come back later after the book is done and see about wiring up a pair of dice as the author has done... could be fun.

I recommend reading over this entire exercise a few times... there is a LOT to sink in. I really like seeing how the author developed the logic of the dice face (LO LO HI, for example) and how he created the circuit to operate in a fairly simple manner... if you were to look at that big, full color patchwork on page 221, you might think this is an extremely complicated circuit... don't let all those wires fool you - all the hard work is being done by the chips.

All in all, a VERY cool experiment and one I enjoyed. I'm going to go back and re-read this entire chapter, because I've been collecting a small list of circuits I'd like to wire up and many of them are going to require chips... lots of chips. So, I want to make sure I have a 100% grasp on this stuff... you should, too.

If any of my readers wire up two dice or move forward with the enhancement, please send me a photo or video (both would be outstanding) and I'll be happy to post an addendum to this one with a few of the best examples.

Still Alive... (great song, btw... name that game?)

2010-04-09T10:24:00.001-04:00

One of my books that I'm writing had it's deadline bumped up by 2 weeks... so I've been working like crazy to get the last chapters done. This means I've had to ignore many of my other projects, including this one... so sorry.

I've got 2 chapters left to write by late next week, so I can take a breather now. I'm hoping to finish up Exercise 23 this weekend. Thanks for your patience.

Chapter 4 - Exercise 23 Update

2010-03-31T21:02:00.003-04:00

Someone please double-check me on this, but I hit a roadblock this week when I realized I didn't have any of the 1N4148 signal diodes specified on page 214. I went back to my shopping list but couldn't find that I'd ever ordered them... I checked all the chapters' shopping lists, but didn't find this particular diode listed. Again, this may be spelled out in glaringly obvious large letters somewhere, but I don't have them in my parts pack, so I had to order them...

... and they haven't arrived yet. I didn't want to make a special drive to ACK for these but it's looking like I'm going to have to do so if they don't arrive by tomorrow.

So, apologies for the lack of posts, but as soon as I can get my hand on these diodes, I've got the rest of the circuit already breadboarded and ready to go.

If this is an oversight on my part, please tell me where they are specified... and apologies in advance to Charles if I'm just plain losing my mind.

Chapter 4 - Exercise 23 Part 1

2010-03-26T10:36:00.003-04:00

I had to really squint to find my 7492 chip - the writing on this particular chip was so small I used my magnifying glass... not kidding.

I've read over the entire experiment and I understand how it's going to develop... so I started by building the first simple circuit. Don't make my mistake and wire it up with standard LEDs... I thought I had mixed in the special Kingston LEDs I ordered from Mouser with my standard LEDs...a bit of digging through the clutter after a few swapped out standard LEDs (small 3mm red that look like the Kingston LEDs) didn't work and I found a small bag with 10 3mm Kingston LEDs in it... put them in and... it worked.

I've included a video here showing it counting from 0 to 5 (binary)... I reordered the LEDs a little different than the one in the schematic so I could see them lighting up vertically.

Have a great weekend, everyone!

Spring Cleaning!!

2010-03-24T15:13:00.002-04:00

As you can see from this photo, my work area has become a hazard area... looking ahead to Chapter 5, I can see a section devoted to getting one's work area organized... I'm going to be moving my electronics work area to the basement (in workshop #1) versus the garage (workshop #2)... I'm going to try and find an inexpensive desk at Goodwill so I can have a place to sit down versus standing... which is how most of my workshop is structured for...

I've also been collecting a few electronics projects here and there to start on once I'm done with the book... not sure if I'll post those at this blog or not - what do you think? Having a dedicated area will be nice... and getting my office back to normal will also be a welcome sight.

Chapter 4 - Exercise 22 - Completed

2010-03-24T14:56:00.003-04:00

Exercise 22 is fairly short, but I can see a lot of uses for the ability to use a NAND or NOR chip to flip back and forth between states and keeping power applied to one or another part of a circuit.

The first video below shows my results with the 7402 NOR chip. The second video is with the 7400 NAND chip. The only differences between the two is how the pull-up (or pull-down) 10k resistors are wired into the circuit and the SPDT switch (whether it's pole goes to positive or negative voltage).

A fun little exercise - be sure to use low current LEDs as the author suggests. I think I used mine although I made a mistake of not organizing all my LEDs I've collected over the various experiments and they're all mixed together... oops.

Chapter 4 - Exercise 21 - Completed

2010-03-22T16:10:00.004-04:00

One thing I'm certainly learning through this process is that no matter how many times you check and double-check your circuit, you've missed something... that is, until it works. The author does a good job of warning us about accidental damage to many components, and my first thought is always "must be a faulty component" - I need to change that to "must be a faulty human."

The good news, for me, however, is two fold - one, my regulator wasn't damaged. But two, the 7432 chip WAS damaged. But the question is whether that damage came about because of my faulty wiring - I'll likely never know, but when I switched out my 7432 (after finding a wiring error - more on that shortly), it started working.

If you look at my picture closely, you'll notice a few differences in the circuit I built and the one on page 210. First, I didn't have a .33 capacitor, so I substituted a 2.2. I tested this before building the circuit and was able to determine that it didn't have any effect on the 5V regulated voltage...

Next, I didn't have two of the 0.01 capacitors so I took a chance and substituted two .047 capacitors for each... I wired them in parallel (opposite of resistors - parallel you add their values) and crossed my fingers that this substitution was okay.

Now - for the faulty wiring. Figure 4-95 on page 210 is fairly easy to follow... but don't make the mistake I did. I had that 10K resistor at the bottom going into the negative column, not the positive. Could that have damaged the 7432 chip? Who knows, but after catching and fixing this error, the circuit didn't work. I went back... carefully checked off each wire in Figure 4-95 and verified I had no shorts and that all wires were done correctly. They were (hopefully).

So next I wondered if it might be a faulty chip - luckily I started with the 7432 instead of the 555 chips... as soon as I replaced the single 7432 with a new one, circuit worked. I pulled it out, put in the old one (same orientation) and the circuit didn't work. Put in the new one... circuit worked. Hmmm... how about that?

I'm including a video below showing the circuit working... I actually soldered wires to my S1 because I couldn't get good connectivity by just twisting the wires into the ends.

So, many lessons learned... again. Check my wiring. It's likely MY fault, not a component. I really am not rushing these builds, but I guess I need to slow down even more... the errors are easily corrected... but also easily avoided if I put a little more effort into slowing down and verifying all my wiring first... I hope my readers are learning from my mistakes and avoiding the frustrations I'm encountering.

Chapter 4 - Experiment 21 - Failed Regulator?

2010-03-22T13:23:00.006-04:00

I had such a great start with the book that I think all the gremlins are now starting to appear... I've got the circuit for Exercise 21 wired up but I'm not getting any voltage on the breadboard. I've taken multimeter readings of my AC adapter... 9 volts there. I've checked all my wiring... so now I'm beginning to wonder if I may have damaged the 5V regulator somehow? Anyone know how sensitive or rugged these little devices are? I've only got one, so I have no way of testing it.

I replaced the two capacitors as well... but no luck. I took a voltage reading across the larger capacitor (.33 in the book but I substituted a 2.2)... it barely reads 1V.

Any ideas? I really can't move forward either since a few of the remaining exercises rely on the 5V regulated voltage setup.

Chapter 4 Experiment 20 - Time to Move On

2010-03-18T21:37:00.010-04:00

Okay, so I took some time away from this experiment, hoping that I'd be able to come back, find my mistakes, and get this circuit working. Well... no luck. But I'd like to try and explain a few things I did differently this time and a few things I was able to verify about the circuit - maybe this will help someone else trying to get this crazy thing working.

First, I totally rewired the entire thing. I found two errors in my wiring on the first try. This time around, I wired up each chip, double and triple-checked the wiring before moving on to the next chip. This worked well, and I was able to get the * button working and lighting up the LED.

After completing the wiring, the # sign would work and light up the LED... but this time I couldn't get the * button to light up - I took a voltage reading - I was only reading 1.0 volt across the LED - I tried different LEDs but no luck. I also tested my LEDs as the # button LED and they worked, so they obviously weren't burned out. My only thought is that they're simply not getting enough voltage. I think I'm using low voltage LEDs but I may be wrong. Either way, why would it initially light up but now now? And it doesn't matter anyway - even if the LED doesn't light up, pressing the * sends current to pin 8 on the 7408 chip, turning it on. The LED is just a visual cue.

Okay, so scratch that... next thing I wanted to figure out what whether the 555 chip was sending any voltage to the LED when the * button is pressed... remember, you have to hold down the * button while entering the code... when I pressed the * button I got a 0.47 volts reading on my multimeter. But isn't pin 3 only supposed to send a pulse if voltage is dropped on pin 2? If I'm detecting voltage on pin 3, this would mean that the 7408 is sending a 1 to pin 3 on the 7404 (a NOT operation) which in turn sends a 0 (no voltage) to pin 2 on the 555 chip. Which means I'm entering the code correctly... so why isn't the LED lighting up? One of the pics shows me using my multimeter and getting a voltage of 0 on pin 3... I didn't have enough hands to hold down *, enter code, snap picture, and hold the probes... argh... so you'll just have to trust me that I got the .47 volts on pin 3...

Oh, well... I gave it a second try, but I think it's time to move on to Exercise 21.

Oh, and there's an unlabeled resistor in Figure 4-84 (I'll submit to errata if it hasn't already been done) - I think it's supposed to be a 10K to match the 10K resistors for the 1 keypad button and the 4 keypad button... I may be wrong.

So, this concludes my attempt at Exercise 20. When I'm done with the book, I may come back and give it one more try... because I hate to leave an exercise with doubts. Is it working? I think so... but I can't get an LED to verify... but I do get positive voltage on pin 3 when I hold down * and press 1, 4, then 7.

So... this leads me to my next contest. I'd like to reward a Maker's Notebook to the first reader who can upload a video showing this circuit working in all its glory... it doesn't have to be mounted to a computer, but it should show all the LEDs working as desired - it should show an improper code being entered as well as the correct code and all the LEDs lighting up as they should - especially the * sign as you hold it down and the UNLOCK LED when the code is entered. First person to post a video that clearly demonstrates the circuit working gets the Maker's Notebook. (Sorry, Charles - as the author, you're prohibited from entering the contest... )

I've got a few videos below to finish up and then it's on to Exercise 21... thanks for sticking with me folks - got a bit behind in "real world" work and had some family business that had to be attended to... but I'm caught up and ready to get back on track.

Components Pack 1

2010-03-18T12:26:00.003-04:00

So, I got my hands on the Make: Electronics Components Pack 1. In my best Vader voice - "Impressive."

First off, the case - hands down, this is one of the nicest storage containers I've ever seen. I've asked MakerSHED to consider selling these individually - they're that nice. (If you agree, add your voice to mine and email MakerSHED and ask them to put them up for sale.)

The pack comes with an inventory sheet, complete with labels for the individual bins and what you'll find inside them. As you can see, this thing is packed - over 350 pieces. I really do NOT want to add up the cost of all the items I purchased that are found in this kit - for $99.00, I'm sure it'll make me cry a bit. Big man-sized tears. If you are serious about following through the book and performing the experiments for Chapters 1 and 2, you'll save a bundle by buying this pre-loaded components pack.

The bottom portion of the case holds many of the larger items - spools of wire, breadboard, AC adapter, and more. The kit even comes with pre-trimmed patch wire - with heavy 22 or 20 gauge end tips exposed. I wish I'd had these when I started! You also get a whole bunch of patch cables (with gator clips on end) - way more than I purchased initially. It looks like the team at MakerSHED really put some thought into what to include that would make the reader's experiences better.

The top portion of the case contains all the smaller bits and pieces -resistors, potentiometers, capacitors, and more. There's even an X-acto knife for trimming away the walls of the spare relay - YES, they included a spare relay just as Chapter 2, Experiment 7 requires!

You've got fuses, batteries, battery holders, those crazy-difficult-hard-to-find 6027 programmable unijunction transistors, and a whole slew of LEDs.

(And for those who pre-ordered, they've thrown in some extras that you'll enjoy... )

The first thing I thought of when I inventoried my kit was how easy this is going to be for me, as a parent, to introduce my son to electronics one day... (if he's interested). Then I realized that, if I were a teacher, this would be something to recommend to those students (and their parents) who show an interest in electronics. Finally, I realized how easy MakerSHED has made it to organize classes around this material - we've got the book and now the components kits - I have a feeling we'll be hearing about "Make: Electronics" classes popping up soon.

If you've ordered the kit, let us know your own thoughts on the pack. And when I get my hands on Pack 2, I'll be sure to let you know my initial thoughts as well...

A slight pause

2010-03-11T13:19:00.002-05:00

I'm heading out of town for a few days... I'm really behind on my "real world" work, let alone getting my exercises done for this book. I need a mental break anyway, so I'll get started again next week... just got a lot on my plate this week and next... but stick with me... I WILL FINISH this book!

Chapter 4 - Exercise 20

2010-03-09T16:14:00.002-05:00

Well, I wired it up... tested it out... no luck. A few parts of the circuit work (such as the Power On LED and the keypad) but not really sure what's going on. As you can see, I didn't spend a lot of time keeping my wiring clean... it's ugly.

Even so, I double and triple checked my wiring and I think I got it all correct. My relay still hasn't arrived so I worked around it by inserting two pushbuttons (lower half of breadboard). I hold down one and that simulates the lower part of the relay being closed... releasing it and pressing the other button simulates the upper portion of the relay being closed.

At this point, I'm willing to go over it one more time (tonight) but I'm ready to move on to Experiment 21. I'll try and come back to this circuit when my relay arrives, but I've been stuck on Exp20 for a bit and am a little tired of it. My goal was to work through all the experiments... and hopefully have them all work. I want a 100% success rate, so I'll likely come back to this one on a weekend when I have some time. (And time is the limiting factor right now - I've got a new book contract that's starting up AND I'm finishing up the editing on another book and that's taking ALL my daylight hours it seems. Alright, enough complaining...)

If anyone has a good clear photo of their breadboard with Exercise 20 all wired up or even a video, let me know... I'd at least like to see if there's anything glaringly obvious that I've done wrong.

Chapter 4 - Exercise 20 Relay

2010-03-05T14:46:00.004-05:00

I decided to cut open the dead relay I had purchased a while back (dead because any voltage applied to it doesn't seem to make the relay click)...

The top-down view is the one that I can best explain. See that white piece of plastic shaped like a T? From the picture's POV, pushing on the top arm of the relay pushes against the piece of plastic and that, in turn, pushes on the second relay arm (on the bottom). But it doesn't work in both directions... pushing on the bottom arm does not move the plastic and the top arm stays where it is... so I've just got to think this through and figure out how this relay works with respect to the circuit I'm building.

Chime in here, folks... it's been a long week and my brain's not firing on all cylinders. Anyone care to take a stab at explaining how this little relay works?

And by the way... the description for this relay is dual coil... is the 2nd coil inside the outer one?

Chapter 4 - Exercise 20 Update 2

2010-03-05T14:11:00.006-05:00

Let me tell you - soldering up the keypad with the ribbon cable is tedious... frustrating... nerve-wracking... and somewhat fun. It looks very Frankenstein-ish and my multimeter tells me all the wires survived the soldering... one or two slight singes as I was putting on shrink wrap, but if I find a wire is bad, I can always make that one of the un-used code numbers, right?

The hard part (for me, at least) is soldering a 22 gauge solid core wire to a 24 gauge stranded wire... hard to make them stay together. Anyone have any suggestions?

Since I'm not going to cut into my wife's PC tower, I think I've come up with a possible variation of this, suggested by the author's text. I think it might be fun to build a box for my son that uses a combination of Exercise 20 and maybe Exercise 11. I could build a noise maker circuit and have it triggered if the code isn't entered properly... or maybe implement the magnetic switches for the alarm system into the box... if the lid is opened without the proper code, the magnetic switch is broken and the alarm sounds. I'll have to think about that...

So, while I wait for my replacement dual coil relay, I'll start wiring up the breadboard for testing...

Also, I had to hunt down the Panasonic DS2E-SL2-DC5V data sheet to understand what's going on inside... here's a link in case you're interested. Page 6 is what you're looking for, DS (2 Form C). I'm still trying to figure out how this thing works, so please chime in if you have an explanation... the more the merrier.

UPDATE: I just created a small circuit with a single LED - I plugged in the wire for pin1 (COM) to positive voltage... and connected the the LED to negative voltage. I then stuck each wire (except for pin 2 which doesn't have a function) into the positive side of the LED, pressed its corresponding button, and hoped it lit up. It lit up for each and every wire. So my soldering worked and the keypad works as desired. That made me happy. Video added below.

Chapter 4 - Exercise 20 Update

2010-03-04T11:24:00.002-05:00

After searching (calling, actually) everywhere in Atlanta, it appears that no one (Radio Shack or ACK Supply) seems to carry the DPDT dual coil latching relay. Argh.

So, I've ordered it from Mouser. But I've got a gripe with Mouser... they do not provide a shipping price until they've actually shipped the order. So I have no real way of knowing what UPS ground is going to cost except for their rough estimate. I'm sure that estimate will be close, but it would be nice to have an actual shipping cost as part of the order before clicking the Submit button. Oh, well.

I've got to solder up that wire ribbon to the numeric keypad today... should take some time as the wires are very tiny and easy to tear.

Chapter 4 - Exercise 20 - Number Pad

2010-03-03T12:58:00.005-05:00

Apologies for the delay in posting... I've got quite a bit of work piled up from a trip out of town and am trying to catch up. Exercise 20 is going to be a multi-part project as I've not been able to find a DPDT dual coil relay locally...

In preparation for the exercise, I purchased an IDE cable (for a hard drive) for $6.00 and cut it so it has 17 wires (14 for the keypad and 3 extra in case I mess up soldering or cut a wire accidentally).

This is tedious - you have to be very careful with the cable because it's so easy to rip a single wire.
I used an X-acto knife to cut each wire apart (except for the 3 spare wires).
I stripped off 1/4" from each end - one end will connect to the 14 solder spots on the keypad... the other end is where I'll solder solid core wire (maybe 1" or 2" strands) so I can use it with the breadboard. As it is, the wire is simply too thin to insert into a breadboard. Once I pick my code, I can save some wire by joining 3 or 4 of the keys not used in the code and then soldering them to a single solid core wire. I don't think I'll be able to solder all 11 unused wires (14 - 3 for code) to a single strand.

I also don't have a spare computer to cut apart and mount this thing - I have 2 laptops and I don't think my wife will agree to let me experiment with her desktop computer.

Now to go find a DPDT dual coil relay...

Make: Electronics Parts Packs

2010-02-27T15:00:00.003-05:00

Some great news - MakerSHED is taking pre-orders for 2 parts packs they've created to go along with the book. Pack 1 has over 200 components... Pack 2 has over 100. Given that so many of the parts are NOT destroyed in the experiments, you'll have a lot of components left over when done with the book to do your own experiments.

You can read the entire news item here. I don't know if Pack 1 covers chapters 1 and 2 and Pack 2 covers chapters 3 and 4... but I'll see what I can find out. With these packs available (mid-March), this will be one of the best teach-yourself electronics courses around... combine the book with these 2 packs and you're in business... great for schools, too, I imagine.

On another note -sorry for the delay in posts. We've had a death in the family and I'll resume posting on Tuesday when I get back in town.

Chapter 4 - Exercise 19

2010-02-23T13:58:00.004-05:00

The section covering Exercise 19 is long... a lot of material. But it's fun reading (at least to me) and not hard to follow.

The first circuit you'll build uses the 74HC00 chip. It performs a NAND operation on the inputs that are fed into pins 1 and 2. The first part of this exercise has you using pushbuttons to control the positive voltage to pins 1 and 2... when the buttons are not being pushed, pins 1 and 2 are connected to the negative voltage side of the circuit (with 10K resistors for protection). The LED will only light up when both buttons are pushed. The first video below shows this in action.

It's on the next part of the circuit where I got a little confused. I wired up everything as seen in Figure 4-79 but when I applied power the LED would stay lit. Only when pushing the single pushbutton did the light go out. It was supposed to be the opposite... then I re-read the section and realized I'd forgotten to swap out the 74HC00 with the 74HC08. Big difference! One is NAND and the other is AND... but with the 74HC00, I got exactly what I should have... the opposite of what happens with the 74HC08. You can see this in the 2nd video.

Also, I had to go back and double-check about the usage of the diode. My diodes have that small gray band on one end and I couldn't remember which direction was which. You only want voltage going back into pin 2 once the pushbutton has been pressed and then the circuit locks. This means the diode must allow voltage to only flow out of pin 3 and into pin 2. I think of the gray band as a wall, so it needs to point in the direction of the LED, meaning no voltage will flow through it when the pushbutton is initially pressed. Since the other end does not have a "wall" voltage flows in the direction away from the LED... or from gray band to no band. (Hope that makes sense...)

Next, I substituted the 74HC08 for the 74HC00 and the circuit worked as described on page 196. Powering up, the LED is initially dark, but a single press of the pushbutton and the circuit locks on and the LED stays lit, even after releasing the button. This is seen in the 3rd video.

A lot of information in this section, so I'll be going back and reading it all again just to make sure I've got it all.

Chapter 4 - Exercise 18 Completed

2010-02-22T11:09:00.007-05:00

I finished wiring up the breadboard for Exercise 18... I went slow and double-checked all my wires, resistors, capacitors, etc... the first video just shows the circuit after I've wired up the first 555 timer chip... you can see it counting up... 2nd video shows it counting up beyond 100. Note that in Figure 4-40 that there is an error reported by another book reader - S5 is shown connected to positive voltage but it really needs to be connected to negative - when the button is pressed, THEN you want pin 4 pulled to negative. I had checked the errata page a while back and saw this upcoming error, so I wrote in my book on this page and didn't make the mistake of wiring it up as shown. Even without the errata page, however, I think I would have caught this, as after all the readings on the 555 chip, I remembered that the resistor used (R10) was a "pull-up" resistor and was meant to keep the voltage positive on pin 4... seeing the pushbutton also connected to positive voltage would have set off an alarm (I hope).

After I verified the counting was working as desired, I finished up the wiring based on the schematic on page 178, Figure 4-41. Be careful here and make sure you have all the right values for the components listed there - especially the 330k resistor (R11) and the 68 microfarad capacitor (C2). I didn't play around with different values here.

The 3rd video shows the circuit working. I apply power and the circuit immediately starts counting. I then press S3 to stop the count and S2 to zero it. Then I press S4 but you'll notice a slight pause before the LED lights up and the count begins. It works!

As the author explains, however, the counting isn't accurate like a stopwatch. To do this, I'll need to add a trimmer resistor (see the photo). It's got a small slot screw on the side that you use to tweak its resistance value... I haven't looked up the sheet on this yet so I'm not quite sure how to implement it into the circuit, but I'll figure that out shortly... not sure if I want to spend a lot of time trying to get it to accurately count in synch with a stopwatch.

All in all, I'm VERY happy with Exercise 18 - take a look at my breadboard closeups. Two months ago, I had NEVER used a breadboard correctly. Really didn't understand how one works. And I most certainly would never have put together something as complicated as this circuit... let alone understand how it works. But I do now! I didn't just look at the schematic on page 178 and plug in all the wires and hope it worked. I really understood how it worked - I understand how the LEDs work, how the 4026 chips work, and how the 555s work... I know what the resistors and capacitors are doing... how the pushbuttons are doing their thing, and, most of all, I really do understand how the reflex tester works as a whole.

I hope all of you who own the book and are working through it are having the same successes (and failures - learning from them, that is) that I am... and I'm only halfway through the book.

I'm still enjoying this process... and can't wait to see what's next.

Chapter 4 - Exercise 18 Almost Done

2010-02-19T14:34:00.005-05:00

So I finished wiring up the other two 4026 chips... still careful about grounding myself before touching them.

As you can see from the pictures, my breadboard isn't nearly as pretty as the author's version (see page 178). Doing this exercise really makes you appreciate the author's hard work with trimming all those wires to make it look pretty - and trimming... and trimming... and cutting... and trimming.

On the positive side, I'm done with most of the wiring... on the negative side (get it - positive, negative) I'm almost out of green wire! Next time I visit ACK I'm going to invest in blue, yellow, and any other colors they may have... red, black, and green are fine, but I wouldn't have minded wiring up the 2nd 4026 chip with yellow and the third 4026 with blue... just to keep everything easy to find.

Anyway, here's a video showing the circuit working... press S3 and it zeroes out the LED. Press S2, and it increments by 1 (most of the time)... holding down S1 locks the LED and any further presses of S2 while holding down s1 don't add to the increment.

One somewhat tricky part of the schematic on page 174 (Figure 4-37) is the jumping of pin 15 on all three 4026 chips and then throwing in a 1k resistor and pushbutton (for S2). I did it on the first try, but you really have to examine the schematics to see how best to make things work.

I'm almost done - now I need to wire in some 555 timer chips and some capacitors to create the reflex tester game. When done, I'll have completed 50% of the book's experiments. Have a great weekend, everyone!

Electronics videos

2010-02-18T16:02:00.004-05:00

Just a quick note - if you're not familiar with Collin Cunningham's videos over at makezine.com, you really should check them out. They're fun to watch, and you'll get some other ideas for experimenting (I especially like his resistor video where he uses a pencil to create a sort-of potentiometer for controlling an LED.)

He's just released a new video on circuit board etching that was really interesting - I've got a ways to go until I get to that point in the game, but nice to know there are kits available that will let you create your own custom boards.

You can watch all of the videos at Makezine.com here... if you're looking for Collin's videos, you can find them all about midway down the right-side of the screen... scroll down until you find the "Make Presents" section - those are his videos.

Now, after watching all his videos, what I really REALLY want is schematics for building that great sound/noise maker he uses at the intro for the Inductor video.

Chapter 4 - Exercise 18 "Thanks, Charles!"

2010-02-18T15:36:00.003-05:00

Well, thanks go to the author for setting me straight and pointing out my error. I cannot believe how simple a mistake I made... and it was staring me in the face the whole time.

As Charles mentioned in a comment on the previous post, many of these breadboards requires you to short the top and bottom halves of the left and right columns... I had done only one of each... you can see in the video that I've now used color wire to represent the positive and negative voltage columns.

Thanks again, Charles! I just knew that it couldn't be three bad 4026 chips...

Now I can get on with the rest of the exercise. (And be sure to catch the switch bounce in the video.)

Chapter 4 - Exercise 18 Debugging

2010-02-18T14:09:00.004-05:00

I'm uploading a few closeup shots here of my circuit as I've assembled it. Ignore the color of the red and black wires I'm using to connect the top of my breadboard to the lower part. I haven't yet purchased blue and red Sharpie pens to color code the columns but if you're looking at the photos, the right-most column is positive voltage and the left-most column is negative voltage. I've also used wires to mimic the setup you see in Figure 4-34 so I can have a positive column running down the 2nd from the left side and a negative column running 2nd from the right.

I've also used my multimeter to check the 9V on the 100 microfarad capacitor at the top of my breadboard AND along the bottom - voltage is consistent across the entire breadboard. I also tested my LED again before rebuilding this circuit and all the segments that should light up are working.

At this point, the circuit is still not working. I substituted a 2nd 4026 chip and no luck. According to ACK Supply where I purchased these chips, they are Thomson Consumer Electronics chips - part # "CD4026BE RCA" - I wasn't able to find a data sheet on this particular chip with the Thomson name, but I did find this one from Texas Instruments. I'm assuming here (maybe incorrectly) that all 4026 chips are supposed to have an identical pin layout... but since I can't find one specific to Thomson chips, this may very well be my problem... but I'm guessing that it wouldn't make sense for different chip makers to switch around the pins. Again, maybe I'm wrong.

If you see a wiring problem, let me know... I used black wires to connect the 4026 chip to the negative voltage and red wires for positive. Green wires are used to connect all the other pins to the LED with the exception of pin 9 where I used a black jumper wire. I'm really hoping this is user error and that I'm just being blind to something really really simple... otherwise, I'm going to have to go and purchase additional chips from a different maker just to rule out bad chips or bad pin layouts.

For right now, I'm stuck...

Chapter 4 - Exercise 18

2010-02-17T15:48:00.002-05:00

I was hoping to have more to post today but I'm a little frustrated with this exercise. I was able to test the three numeral LED (see video below) but after wiring up the very first 4026 chip, I got no response on the LED. I double and triple checked all my wiring using Figure 4-35. I made sure the pins that went to negative voltage went to negative... and the pins that wired to positive voltage were wired to positive.

I checked my pushbutton with an LED - I had it wired correctly.

I checked the 9V voltage... all columns were registering the 9 volts and I properly wired up the columns as seen in Figure 4-34.

So, I grounded myself (again) by touching my metal table... pulled out another 4026... wired it up and pushed the button. Nothing.

Ditto with a 3rd 4026 chip. At this point, I went back to my wiring. The notch on the chip is pointed up (away from the LED) so that would mean pin 1 is upper-left. I again verified all my pins were wired up but nothing. Either this 4026 series of chips I bought isn't working with 9V (and I bumped it to 12V but still no response) or I'm doing something seriously wrong.

I spent over an hour wiring and rewiring just a single 4026 chip... I've got to take a break from this and come back after I've not thought about 4026 chips for a while.

Anyone else have luck wiring this up using Figure 4-35? I just find it hard to believe that these 4026s can be that sensitive... I may have to go buy more before I can finish this exercise... but I'm hoping someone has a suggestion because I'm flat out of ideas.

Contest #2 Winners

2010-02-16T15:14:00.002-05:00

Back on January 31st, I asked readers to writeup a small comment about their experiences with the book, good or bad. Out of the 6 valid responses, I picked two names at random: Mike and Skain.

I need Mike and Skain to email me so I can tell them how to get their Maker's Notebooks. Thanks to all of you for your comments which I hope Charles Platt and MakerSHED find useful.

Chapter 4 - Exercise 17

2010-02-16T13:27:00.005-05:00

For Exercise 16 I built the circuit towards the bottom of the breadboard... if I had read ahead, I would have seen that Exercise 17 was built towards the bottom. Oh, well... in my pictures, the LED circuit (Ex16) is at the bottom and the speaker circuit (Ex17) is at the top.

For the exercise, I (once again) lacked a .047 microfarad capacitor. But luckily, this circuit is all about flexibility. R1 and C1 are the controlling components that will allow us to modify the sound emitted by the speaker... so, on page 166 I noticed that the author included a few capacitors in there that I did have - namely 4.7 microfarad and 47 microfarad. The chart indicates that I should get some sort of sound from the speaker... so let's see.

First, I installed the circuit in Figure 4-21 using a value of 4.7 microfarads for C1. All other components were as listed. Because I'd already wired up C3 in Exercise 16, there was no need to do that again. Remember, C3 is for smoothing the voltage provided by the 9V power supply and the author recommends always including this for integrated circuits.

The first video below will show you that my speaker is emitting a low but fast sound... and the LED circuit is still working.

Next, I removed the 4.7 microfarad (C1) and replaced it with a 47 microfarad. The second video shows the results of that exercise. As you can hear, the sound is much slower and lower... almost like a fast ticking of a grandfather clock. (That loud clicking sound you often hear in my videos is a foot pedal power switch I have installed... I leave the foot pedal plugged into the wall and plug in my adapter to the pedal... I press the pedal with my foot to turn on and off the power.)

Finally, I shorted the power (pin 8) for the speaker circuit to the output (pin 3) of the LED circuit using the long red wire seen in the photograph. I turn on the power (with my foot pedal, but not heard in the 3rd video) and the speaker will not emit any sound until I press the button on the LED circuit... notice also that the reset (pin 4) button immediately kills the sound coming from the speaker.

There is a LOT of information in Exercise 17... I plan on re-reading it once or twice... I may even go back and read Exercise 16 and 17 together... I think we all need a solid understanding of what's going on here - especially the descriptions provided on pages 158 and 164 where the timer chip is explained with a little more detail. What's working for me now is I'm totally understanding how all the components in these circuits are working together to give me the expected results... I understand WHY that capacitor is where it is... WHY that resistor is necessary... WHY that second capacitor is there and WHAT it's used for...

Also, don't skip the last sections on chaining chips together... I had to read it a few times to sink in and I still need some time to process it all. I think knowing that it's hard to damage the 555 timer once it's installed in the circuit makes it easier to play around with the various components. Be sure to work through some of the modifications mentioned on pages 168-169.

Finally, if anyone tackles Figure 4-29, please let me know. I may try it this weekend when I have some extra time, but I really don't want to slow down on the book and this one looks tricky to implement. I have 10 of the 555 chips, so I've got enough to give it a shot, but if anyone has tried it or plans to do so, let me know.

Recovering from The Crud...

2010-02-15T14:07:00.000-05:00

Sorry I've been away for a bit... haven't forgotten about the book... just been sick with something that took me out for a few days and then came back with a vengeance. I think I'm finally on the mend, so I'm going to try and get Exercise 17 completed today and hopefully have it written up and posted tonight or tomorrow...

The Mouser Encyclopedia

2010-02-11T14:20:00.003-05:00

I just checked my mail... crammed into the mailbox was this 2190 page catalog. I'm guessing that if it is an electronics component and someone makes it... it's probably in here.

And what really strikes me as funny is that this is the February to July 2010 catalog... so I'm guessing I'll be getting another one of these in July or August... I'd really prefer not to, so I'll probably call them and ask them to take me off the list. I can't imagine the catalog changing all that much (except maybe for subtle price changes). The little bit of environmentalist in me figures I'd rather save the 2 or 3 trees it takes to print this thing... just a thought for those of you placing orders with Mouser.

Chapter 4 - Shopping List

2010-02-11T13:51:00.004-05:00

I gathered the Chapter 4 components and tools from a variety of sources.

Below, I've included description, part #, price, and where purchased.

Looking online, I paid way more than I should have for the various chips, but I was able to obtain them locally and visually inspect them. I also got a 20 minute education in other chips, so I figure the extra I spent was worth the extra information... future chip purchases, however, will likely come from Mouser.com where I think I see the best prices... please feel free to chime in about what you've found in terms of prices.

Components

ACK Supply for all chips below:

555 Timer chips x10, CA555E RCA, $0.80 each
$1.59 each for
CD74HC00E RCA
CD74HC02E RCA
CD74HX04E RCA
CD74HC08E RCA
CD74HC32E RCA
CD74HX86E RCA

CD4026BE RCA, $2.59 each

7492, $2.05 each
7406, $1.67 each
74LS27, $1.59 each

-----
Radio Shack Online items below

Item: 2761995
Description: 8-Pin Retention Contact
Quantity: 5 @ $.48

Item: 2761999
Description: 14-Pin Retention Contact
Quantity: 5 @ $.99

Item: 2761998
Description: 16-Pin Retention Contact
Quantity: 5 @ $.99

-----
AllElectronics.com items below

12-key numeric keypad - KP-12 (12 BUTTON KEYPAD - (KP-12)) $4.95

-----
Mouser.com components below

638-HLMPK150 Red LED, 660nm, $0.18 each

604-BC56-11EWA,HI EFF RED DIFFUSED numeric display, $2.73 each

Latching Relay 769-DS2E-SL2-DC5V 2A 5VDC DPDT, $4.86 each

10K Trimmer 652-3266Z-1-103LF 1/4" 10Kohms 10% $2.94 each

Voltage Regulator 512-LM7805CT 1A Pos Vol Reg , $0.37 each

Tactile Switches (already purchased for earlier chapter)

-----
Radio Shack Store components below

100K Potentiometer, 271-092 $2.99 each
10K Potentiometer, 271-1715 $2.99 each
5K Potentiometer (already purchased for earlier chapter)

Chapter 4 - Exercise 16

2010-02-11T10:21:00.003-05:00

Chapter 4! Finally getting into integrated circuits which have always interested me but I've never quite found a good explanation for how to use them or how they work... until now. That said, I did have to read over this first material about 3 times before it really sunk in. But it's now "sunk."

This exercise is all about the 555 Timer chip. My initial thoughts before reading this chapter was that this was a timer that would keep time... right? Like a stopwatch. Wrong... sort of. I guess it can be used that way in certain circuits, but it's really about holding a pulse (current, I think) for a certain amount of time... an interval that we have control of, by the way. By changing the values of different components, we can manipulate a pulse emitted (allowed?) by the chip to last a specified time (with slight variations).

My photos here show the circuit I built using the schematic on page 155 (Figure 4-15). I tried my hand at building the circuit by only reading the circuit and not looking at Figure 4-16 for help. I got it right the very first time... I was happy about that.

A few differences, though - I lacked a 100 microfarad (C3) capacitor so I substituted a 220 microfarad... since this is for voltage smoothing, I was guessing that as long as it was a minimum of 100mf that I'd be okay... wasn't 100% certain, but willing to experiment. The rest of the components I had in my kit... be sure to note that the voltage has been switched on the breadboard to 9V and the sides are changed - positive voltage on right side, negative voltage on left side. I also had to go back and refresh my memory about the symbol for an LED because I couldn't remember if the long wire was where the arrow was pointing to or away from ("away" is the answer).

Also, be VERY careful with the orientation of your electrolytic capacitors and make certain their positive and negative terminals are inserted into the breadboard properly. Luckily I checked over my components before applying power and discovered I'd reversed C4. I also soldered two lead wires to my potentiometer to make it easier to insert into the breadboard and avoid using patch wires.

Below are three videos - for the one with R4 equal to 100K, the LED stays lit for about 5-6 seconds... difficult to measure it accurately at this point. I next more than doubled R4 to 220K and, as expected, the LED stays lit for well over 10 seconds. Finally, I cut R4 in half and substituted a 51K resistor and the LED stays lit for around 3 seconds. I wanted to mess around with different capacitor values, but my capacitor selection is limited and they are also not as easily doubled and halved in values like resistors.

It does bring up a question which I don't think I've seen covered in the book yet - can you add capacitors like resistors? If I add two 47mf capacitors in series, will it behave as a 94mf capacitor (close to 100mf)? I may play around with this but am not certain if I'll be risking my components... just not sure if this is safe or not. And I don't have enough capacitors to play around with right now, so I'll likely pick up a mixed bag some time this weekend.

I enjoyed this chapter - I'll likely go back and read over this material one more time before starting Exercise 17... not all the pins on the 555 chip have been covered in detail so I'm still fuzzy on some of their uses, but I definitely understand how pins 2, 3, and 4 work and I'm getting better at pins 6 and 7...

Chapter 3 - Exercise 15 Completed

2010-02-09T15:36:00.003-05:00

A short post and summary today - I've got myself a cold and am not feeling so well.

I got the project box completed - soldered up all the LEDs, button, switches, speaker, etc. I left the power jack on the bottom unfinished... since I don't have a 12V power supply to spare, I'm not sure if I'll complete that part of the project any time soon.

A few notes about the project box - I had to redrill the four holes in the circuit board to mount them to the box - I used a 1/8" bit to enlarge the holes and I purchased 4 #6 bolts to fit in the four holes I drilled in the back of the box. I bought 4 small nylon nuts (#8s) to serve as little posts for the circuit board to sit on... works fine.

The project works... sort of. The green LED does not light up to test the circuit - either I burned it out (I did use a copper clip) or soldered something incorrectly, but I just can't get that part of the circuit to work. The box does work, however. When I have the magnetic switch closed (see video), I can flip the power switch - the red LED lights up. When I break the magnetic switch, off goes the alarm.

I'm ready to move forward (once I get to feeling better) and away from the exercise, so I'm going to put this aside for now and maybe come back to it in the future to try and figure it out. For now, I've learned what I can from this exercise and am looking forward to Chapter 4 that starts us on Integrated Circuits... woo hoo!

Chapter 3 - Exercise 15 Part 6

2010-02-08T14:44:00.005-05:00

Today I worked on the project box. I didn't have the DPDT pushbutton recommended for the project so I substituted a DPDT switch as seen in the pictures. Unlike the pushbutton, I'll have to switch it off manually to stop testing the circuit.

Just an FYI:

* *For the LED holes I used a 3/16" bit
* For the speaker connectors (on bottom of faceplate) I used a 1/8" bit
* For the speaker holes I used a 1/8" bit
for the power jack I used a 11/64 bit"
* For toggle switch (power) I used a 3/8"
* For test DPDT switch I used a 5/8"

Measure your own components, though - I can't guarantee your components will be the exact same size.

For the speaker hole layout, I just used a graphics program to create it and printed it actual size (2" diameter speaker). If you want to use mine, feel free to grab it here. (I'm using MediaFire.com and am not sure how long this file will be available.)

I cut out the printout, taped it to the back of the faceplate and then used a drill bit and hammer to make small dimples in the center of each circle... helps later when you drill them.

As you can see, my project box is almost done... I need to solder it up and make all the various connections. Almost done!

Chapter 3 - Exercise 15 Part 5

2010-02-07T14:15:00.005-05:00

I am smiling ear to ear today... my confidence in soldering just doubled as I was able to move the circuit from the breadboard to the perfboard, little by little, and get it working. For me, one of the keys I feel to my success so far was getting it working on the breadboard first... troubleshooting various issues - wrong resistors, bad transistor, etc - and testing every step of the way.

Last night I successfully moved over the top half of the circuit to the perfboard. As I mentioned in the last post, I soldered each component and then attempted to test my soldering when possible... I used the multimeter to make sure the resistance values were accurate (use the holes in the perf board, not the resistor leads). I also tested voltage across the capacitors to make sure those were soldered properly, too. I haven't yet found (or heard of) a method for testing the 2N2222 and PUTs once soldered, but maybe someone knows a way?

Today I went and purchased a few extra capacitors of various capacitance but was unable to find the 2.2 microfarad capacitors with both leads on one end (shaped like a barrel) - I could only find non-polarized 2.2s with one lead on each end... argh. So, I decided to substitute a 4.7 microfarad for C1 (just like I did for C3)... took a chance because I didn't know how it would alter the circuit, but I felt it was a reasonable risk given the close values. I got home, soldered in the missing capacitor, and tested the top half of the perfboard consisting of the noise maker - the first video below shows my results.

Next, I started moving over the bottom portion of the circuit - the relay/power section. It had fewer components and was slightly easier to solder because not many of the components are sitting next to one another... the exception being the Diode and R1 and R2. (Note: The R1 and R2 on page 135 is NOT the same R1 and R2 in the circuit on page 91.)

Once again I was a little nervous soldering the 2N2222 because those little leads are so close to one another. And pushing my relay through the perfboard was tricky... the holes were just a little too small and my pushing it felt like I was going to snap the perfboard in half... it did finally go in, but it took a couple of minutes of very careful pushing and widening the holes with a large bore needle.

After the circuit was transplanted to the perfboard, I soldered various strands of wire in place - two green wires that will go to the magnetic switch(es), two black wires (twisted together) that go to the speaker, and a red and black wire (twisted) that will provide power.

My second video shows my testing of the circuit outside of the project box. I used gator clips to hold everything together and crossed my fingers...

All in all, I'm having a blast with this book. The heartbeat LED project (Experiment 14) was fun, but this one is really cementing what I've learned about the way resistors, capacitors, transistors, relays, and diodes are working together. Now I've got to get the project box prepared so I can mount the circuit board and close up the box.

Chapter 3 - Exercise 15 Part 4

2010-02-06T22:18:00.005-05:00

I finally got the alarm circuit working for Exercise 15. There were two problems, one human-error and the other not:

1. The two 470K resistors required by the circuit - I was using 470 ohm resistors... HUGE difference! But after finding and replacing them, the circuit still wasn't responding... I had tested all the connections with the multimeter and the LED was working for some reason, but no sound...

so...

2. I swapped out one of my 2N2222 transistors with a new one... Bam! Alarm started working. Swapped out the replacement with the old one... no alarm. Bad transistor...

So, now that the circuit was working, it was time to start soldering it, piece by piece, to the small perfboard I bought from ACK last week to fit in the project box.

First off, these little perfboards are nice and cheap... BUT... the copper tracings you have to solder to are VERY VERY close together. I was worried about soldering the transistors and PUTs because the three leads are so close together. One of my photos shows a closeup and you can see how each row of 6 holes are connected via the copper and how close they are to the row above and below it. Very easy to short circuit if a little solder bleeds over to another row...

As I soldered each item, especially the resistors, I would use my multimeter to check the joint - it's easy to insert the sharp points of the probes into the small holes and see if the reading gives you the proper resistance... all of my resistors for the top half of the circuit are properly soldered... but I can't say the same for the transistors - close examination with my magnifying glass looks okay, but some of those little blobs of solder are awfully close to one another.

I also couldn't fit my large 2.2 microfarad capacitor into the circuit - the capacitor I had had the leads on opposite ends instead of the same end, making it hard to fit the large capacitor (relatively speaking) in place... I'm going to have to purchase a replacement 2.2 that has both leads on one end so I can fit it on the board... it'll go in the upper-right corner in case you're wondering.

I took my time soldering the top half and will do the same with the bottom half of the circuit - but I'm still nervous about shorting out some of the circuit with my not-so-professional soldering skills... but fingers crossed.

Lastly, I'm including a video of the fully wired up alarm system working on the breadboard - if it doesn't sound like yours, please remember that I substituted a 4.7 microfarad for the 2nd 2.2 microfarad and I'm sure it changes the sound a little bit.

More Make: Electronics blogs

2010-02-05T18:13:00.001-05:00

Two more blogs with coverage of the various experiments in the book - if you know of any more, please let me know.

Painless Technology

Domo Domo

Chapter 3 - Exercise 15 Part 3

2010-02-05T15:57:00.003-05:00

Today I wired up the alarm system portion of the breadboard... once again, I lacked two 2.2 microfarad resistors so I substituted a 4.7 microfarad for C3 (in Figure 2-113). When I wired up this noise maker using that combo, it worked... but probably didn't sound exactly like it should with two 2.2 microfarads...

I also modified the relay circuit to look like the one in Figure 3-95. When I break the magnetic switch, I hear the relay kick in and it locks, too - resetting the magnetic switch doesn't turn it off.

I hooked up the speaker... flipped the power... broke the magnetic switch... and nothing.

Argh.

(Keep in mind that I'd already used my multimeter to test voltage/current settings - there was a charge of almost 12V built up on C1 capacitor... and about 11V on the two wires I used to connect to the speaker... so... faulty speaker?

Instead, I connected an LED in place... and it worked. The LED lit up just fine... but shouldn't it pulse? I rechecked all my wiring and components... everything where it should be and voltage across the LED... enough to light it at least. But not enough to get me any noise from the speaker. So I'm back to testing... probably won't get to it until tomorrow, but I'm anxious to build this device, so I'll do my best to figure it out... suggestions or tips welcome.

Movie of the LED lighting up below...

Chapter 3 - Exercise 15 - Relays the Same?

2010-02-04T20:34:00.003-05:00

I may be wrong here - I hope Charles Platt will set me straight - but I think the relay used in Exercise 15 is slightly different than the one we used back in Chapter 2 Exercise 7.

The drawing for Exercise 7 shows the arm of the relay, when the coil isn't powered, pointing in the direction of the coil. When the coil is powered, the magnetic field it creates pushes the arm away (upward). This caused the 2nd LED to light up in Figure 2-60.

But in Exercise 15 the relay shown there has the arm in the "up" position, away from the coil. When the coil is powered, it pulls the arm towards it.

When I was building my circuit, I was using a relay where the arm was pointing towards the coil when not powered... I had to visually inspect the opened one (Exercise 7) to see this... once I saw that, I was able to properly wire my circuit. If I had to modify the circuit in Figure 3-93, I'd have to show the anode of the diode connected to the right-most pins (the one the arm is shown pointing at in Fig 3-93). I hope this makes sense... if we're to assume we're using the same relay from Exercise 7 here, then the circuit in Figure 3-93 would also need to have the arm pointing towards the coil.

Chapter 3 - Exercise 15 Part 2 - It works!

2010-02-04T20:16:00.005-05:00

Okay, it was bugging me all afternoon that the circuit wasn't working - and I had a gut feeling it was my wiring, not any of the components. I was careful to identify the anode side of the diode, too... be careful about that.

Anyway, I kept looking at the circuit and then I saw my mistake. I had added the diode into the circuit but I had never connected the coil pin of the relay to the anode side of the diode... I'd left it connected straight to the emitter of the transistor. I'll have to sketch this out and figure out why that mistake kept the relay from locking, but I'll do that later... for now, I'm just happy to have figured out the error (my wiring). This is just more evidence that I need to go slower when building my circuits and check every connection in addition to checking voltage/current with my multimeter.

So, here's a video of the circuit working as it should... when I pull the magnet away from the reed switch, you'll hear the relay click once... and then no matter how many times I push the magnet back onto the reed switch, the relay will not release... it's locked.

I have to admit - it's always nice to figure out your error on your own. I'm including two close-ups of my working circuit - I'm not sure if I've made the wisest/best use of the breadboard, but hey... it works. Now I can continue with the rest of Exercise 15.

Chapter 3 - Exercise 15

2010-02-04T14:00:00.007-05:00

Exercise 15 starts out with a small circuit that uses a break in the circuit to trigger an LED to light up. The 2N2222 transistor is used in this circuit, and it's fairly easy to see how it works. I wired in one of my magnetic switches and, after powering up the circuit, pulling away the magnetic end of the switch causes the LED to light... moving the magnetic end back to the reed switch causes the LED to turn off. One of the videos at the end of this post shows this circuit in action.

Next, I removed the LED and 680 ohm resistor as instructed and replaced them with my 12V relay. The idea here is the same... when the magnetic switch is broken, current is allowed to flow through the transistor and triggers the relay... you can't miss it - it's a definite audible click. Pushing the magnet back to the reed switch causes the current to stop flowing and the relay turns off - another click. I've included another video at the end of this post that shows this happening.

Now, the section on Self-Locking Relays makes sense... I read through it twice and followed the circuits and I completely understand how it works... in theory. But building the circuit is another issue. There's no wiring/breadboard diagram here to reference, so I did my best and one of the photos here shows my completed circuit. The problem is that the circuit isn't working the way it's supposed to... when I pull the magnet away, I hear the relay switch on... but it's supposed to lock - if you look close, you can see that I've applied 12V to the middle set of 3 upper terminals on my relay... corresponding to the small arm that moves inside. Moving the magnet back to the reed switch isn't supposed to turn the relay off... but it does. I've got a final video where you can here the relay opening and closing as I move the magnet back and forth.

So, I'm stumped. For now. I'm sure it's something simple that I've missed, and I have a feeling it's related to the fact that there are matching sets of terminals on the relay and I'm likely not wiring one or more of them up properly. From the schematic on page 132 (Figure 3-91) you can tell that the lower two posts of the relay are supposed to be connected - the one on the left connects to the Emitter of transistor... the one on the right connects to the negative voltage. But shouldn't the middle set of terminals (for the moving arm) have it's right-side terminal also connected to the negative voltage? Look at Figure 3-95 on page 135 and you can see that there's a wire added from the middle set's right terminal to the negative voltage side.

Any ideas? My circuit is upstairs, waiting to be fixed...

UPDATE: I went back to Figure 3-91 and thought I'd found my mistake... there's a connection between the Emitter of the transistor and the ON post of the relay. I cut a small piece of wire and connected the Emitter to that post (on the left side of the relay inserted into the breadboard). Turned on the power and the relay went CRAZY. High pitched whining sound that probably isn't a "good" noise. Removing the magnet made it stop, but putting the magnet towards the reed switch caused it to go noisy again... so I'm still missing something...

UPDATE 2: Okay, I happened to glance over at Figure 3-93 and noticed that diode sitting there in the circuit. Of course, I've only read over the Blocking Bad Voltage section once - need to read it again - but I did seem to recall something in there about feedback... so I went up and added in that diode and the noise stopped! Okay, problem is partially solved. It STILL isn't working quite right - when I pull the magnet away (simulating a door opening) the relay is supposed to lock and not disengage when I put the magnet back (closing the door). But it does... argh.

UPDATE 3: Just a warning - these updates could run into the hundreds. Kidding. I went back and took a look at the relay that I tore open in an earlier chapter. It turns out that my relay is off when the arm is in the "down" position, pointing towards the coil. Easy enough - I rewired it so the top post is connected to the diode's anode side. But the relay still isn't locking as it should... something is missing from this circuit... just can't figure out what.

Chips for Chapter 4

2010-02-04T12:41:00.004-05:00

In anticipation of Chapter 4, I've begun my search for the various chips used in Chapter 4. You can spend hours at Mouser.com or AllElectronics.com scanning through all their chips. One frustrating thing at AE was that in some instances, typing in the shortcut name such as 74HCXX wouldn't pull up anything... other times it did. I had better luck with Mouser but in some instances the picture was wrong - it would show a non-DIP switch for the thumbnail but the description/part# was what I wanted... OR... the picture was right but the description didn't match.

Rather than take a risk of ordering this stuff and not getting EXACTLY what I wanted, I chose to shop locally and pay a little more per chip. I was able to visually inspect every chip for the ID# and make sure it was of the DIP type. I also got all the chips inserted into two long plastic tubes that protect the chips legs/prongs from bending... not sure how Mouser.com and AE ship the chips, so please let us know if you order any and how they are shipped.

I got all my chips at ACK Supply here in Atlanta... definitely higher in price per chip but after looking at the shipping costs at Mouser and AE, it'll just about even out...

If you want to order from ACK, call 1-800-282-7954 and ask for Scott - just the 20 minutes he spent talking to me about the differences in chips, explaining the other letters not covered in the book (such as low voltage chips or military grade), and showing me some other chips I'll likely want to buy a few of later... totally worth the drive and extra cost. He was even able to help me find a replacement for the protoboard required in Exercise 15 that RadioShack no longer carries. I was able to fill my entire chip order with one visit and learn some more stuff to boot... nice guy.

Chapter 3 - Exercise 14 Completed

2010-02-03T14:07:00.005-05:00

Well, it took forever and I burned out a couple of red LEDs in the process, but the thing is working. I ended up soldering some longer strands of wire to the shorter pieces and used shrink tubing to cover up the joints.

Somehow I managed to fit it all into that little box -what a pain! But a flip of the switch and it takes a few seconds to charge up and then the red LED starts its pulsing. Very cool.

I've had enough of this project, so here's a final video of the box in action... I'll probably get a red Sharpie and draw a heart around the LED and write something cheezy on it... "My heart beats for you!" - that sounds good.

Anyway, on to the Exercise 15... it's a long section and looks like a handful. No idea how many parts I'll break that up into but I know it'll be more than one.

Welcome to New Readers

2010-02-03T08:47:00.002-05:00

My blog traffic just took a major jump... I usually see this when Makezine.com has a small blurb about my writeups, but nothing like that happened yesterday. Hmmm....

Anyway, I just wanted to welcome new readers to the blog - I'm still fully committed to completing all 36 experiments, but if you're keeping up with me in the book (or have read ahead) you know that the experiments are getting a bit more complex, the chapters and experiment writeups a bit longer... all this means is that completing all 36 experiments may take a bit longer... but we'll get there!

I'll have my Exercise 14 creation completed today and will try and jump into Exercise 15...

Again, thanks to all my readers for joining me here... and for your comments.

Chapter 3 - Exercise 14 Part 3

2010-02-02T11:35:00.006-05:00

Oops... I was wrong. Exercise 14 will be four-part series... sorry. I'm THHIIIIISSS close to finishing it.

Okay, so I've done some more with the small circuit. Yesterday I mentioned that I was adding in a switch and two 3V coin battery holders. The hard part is just keeping track of what is soldered to what... so I've been drawing a LOT of schematics and sketches.

One thing I learned from an earlier troubleshooting job (and one that got me some jabs from some commenters about not testing my circuit with the multimeter - all worthy jabs, I might add) was to test your circuit often... don't build the entire thing and then flip the switch and hope it works. So, I took their advice and hooked up the unfinished circuit at various points... one of the videos below shows a whole bunch of patch cables that I needed to test the wiring... it worked, but it's a real rats nest of wiring. (Another thing I learned from this - you can never have too many patch cords - I'm going to buy another 4 or 8.)

Now, please be kind and realize that I'm new to putting a circuit together with a soldering iron AND I'm new to laying out circuits AND I'm not 100% sure of how to wire the LED and Switch up since they won't be connected to the actual perfboard... I'm learning as I go. I think I'm going to have to use some of my braided wire (that's more flexible) so I can make all the connections. We'll see.

Anyway, here's a lot of photos and a few videos of today's work. The second video is where I've almost got the circuit 100% completed. The three solid copper wires you see poking up from underneath the perfboard - one is the + voltage, another the - voltage, and the other the R5 wire that will connect to the Anode of the LED. Hope this is making sense. You can see in the 2nd video that I've reduced the number of patch wires used in the first video and have added the switch into the mix... it works! Woo Hoo!

I've drilled the holes (side and top) and had to trim the box's left side a little so I could close the top (the switch kept it from completely closing). Another photo shows me testing that voltage is flowing - a little over 6V.

Now, hopefully no mistakes as I finish up connecting the LED and Switch wiring and close up the little box. But first, a paint job for the little box...

Chapter 3 - Exercise 14 Part 2

2010-02-01T15:42:00.005-05:00

It's looking like Exercise 14 may take three posts... I'm not quite done with the circuit yet.

As you can see from one of the photos, I had to draw it out to understand it - I'm going to add in a small switch and I needed to figure out where it fit in the circuit. Because I'm using two CR2032 batteries to power this thing (6V), I also needed to put them in series. I think I've got the drawing done correctly...

I started by soldering the two battery holders to the small perf board. I arranged them in such a way that I could solder a small strip of wire between the positive and negative terminals, leaving a positive and negative terminal un-soldered for later. I added in the two capacitors because they share a soldered joint and this would help hold them in place.

Next, I added in R4... it shares a single joint with the positive wire on C1. Then came the 2N6027 PUT. The only tricky part here was trimming down the wires so I didn't create any shorts... some of my joints are spikey little things and I just can't seem to trim them much closer without possibly damaging the soldering I've done. Luckily, I think most of my soldered joints are well clear of one another... my photos should show what I've done (sorry for that one blurry one)...

Next, I've got to drill a hole in the side of my project box where I'll mount the switch. I thought about putting it on top but there's not a lot of room for the lower portion with the terminal posts... plus I like the look of it on the side. Flip it up, the circuit will turn on... flip it down, the circuit turns off. The LED will be the only thing mounted in the top, and I've got to drill a hole for that, too... probably tonight or tomorrow. After drilling the holes, I want to paint the box white, maybe add a mushy Valentine's Day message somewhere on the contraption, and I'll add this to the stuff for my wife on V-Day. Silly... cheap... turns on, turns off... worth a few Husband Points.

Contest Winners - and a New Contest

2010-01-31T19:36:00.004-05:00

Back on January 13th, I created a small contest asking readers to help me understand better the circuit seen in Figure 2-60 on page 59. I was having difficulty understanding how the circuit was working... mainly because my limited training in electronics was always about closing a circuit. I could NOT, for the life of me, see how the circuit was closed in Figure 2-60. With the pushbutton open, I saw no closed loop.

But the circuit in Figure 2-60 isn't drawn like a typical circuit. The positive and negative voltage terminals are not drawn together. That's what took me a bit to see... and once I did, I saw the loop. See, in most circuits I'd seen or drawn, the battery (or power) was always drawn with the same symbol... current came out one end and went back in the other... there's your loop.

But with 2-60, the closed loop is there... it's just not drawn that way. You can, for all practical purposes, consider the small black dot just to the right of the big red + sign and the other black dot to the left of the big - sign as touching... if you do that, the circuit is closed.

Okay, enough of that... to the winners. Well, I only had two submissions... so this is an easy one. Both Brian and Nick will each get a Maker's Notebook.

Brian and Nick: I need you to email me at jktechwriter *at* gmail dot com with your mailing addresses... in order to confirm you are who you say you are, I'll email you instructions for confirming you were the person who posted the item. I wouldn't want to send a book to another Brian or Nick!

And now another contest - for this one, I'll be picking two winners - each will receive a Maker's Notebook. This contest is about helping out Charles Platt, author of the Make: Electronics book, and MakerSHED. Here's all that you need to do:

1. Add a comment to THIS post - January 31, 2010 "Contest Winners - and a New Contest."
2. Your comment should be between 50 and 100 words.
3. Let Charles and/or MakerSHED know your thoughts on the book - tell them what you like, what you dislike, or what other books/projects you'd like to see from MakerSHED.

That's it - I'll pick two winners randomly on Feb 13, 2010 so I can award two Maker's Notebooks on Valentine's Day. I'll number all the comments, write down each number on a paper chit, and have my wife pull two numbers randomly from a hat. Two minutes of your time for a chance to win a $20 Maker's Notebook. USA residents only, please.

Chapter 3 - Exercise 14 Part 1

2010-01-31T17:25:00.007-05:00

I'm breaking the post for Exercise 14 into two posts. For this first part, I've breadboarded the circuits found on page 118 (Figures 3-75 and 3-76). I initially tried to substitute the 220 microfarad capacitor for C1 because I didn't have a 100 microfarad capacitor... the LED just stayed lit... no blinking. So, yesterday while I was out running errands, I swung in and picked up a few things from Radio Shack. More on that later.

This is the first time we're given a schematic without a matching breadboard drawing - I tried to build the circuit without glancing back to page 85 for help... my first attempt worked, but even with the proper 100 microfarad capacitor, the LED stayed lit... so I knew something was wrong. After checking my circuit again, I found I'd made a few connections wrong with the 2N6027. A quick glance back to page 85 also helped me make sure I'd wired it up correctly. I highly encourage you to try and wire it up without looking at page 85... but if you get stuck, the photo to the left is a closeup of my circuit that works.

After testing that circuit, I moved on to Figure 3-76 and added in C2 and the 330 ohm resistor. I got it correct on the first try... again, try to do this yourself... but if you get stuck, my photo shows a closeup of the breadboard layout that I used successfully.

I'm including two videos here - the first shows the single C1 circuit... the second shows the circuit with C1 and C2. The red LED pulses nicely. After reading ahead in Exercise 14, I found the author is suggesting mounting the LED in some acrylic to make it all look pretty. I think I'm going to try something different... let me explain.

I switched the voltage from 9V to 6V because I found two small watch battery holders (solderable) at Radio Shack for $0.99 each... I also purchased a small project box and a perf board that can be broken in half - one half will fit nicely in the box after I trim the edges a bit. Doing this will also require that I rearrange the layout of the components found in Figure 3-79. I'm okay with that, and I think Mr. Platt would be, too. We're supposed to be experimenting and trying new things, right? I'm including a photo here of the parts - and I'll also provide a parts list and pricing below. No guarantee it'll work, but it should be fun to try.

Up next, I'm going to start the soldering... as you can see, my soldering will differ a bit from Figure 3-79 but I'll try and do my best to photo and explain my layout in the next post.

Coin battery holder CR2032 - Part 270-009 $0.99 each
220 microfarad - Part 272-1029 $1.29
100 microfarad - Part 272-1028 $1.29
PC Board - Part 276-150 $1.99
Project Box Small - Part 270-1801 $2.29

I hope everyone had a great weekend!

Chapter 3 - Exercise 13

2010-01-29T14:47:00.004-05:00

For this experiment, I used a green LED and a yellow LED. The green one got the 15W treatment followed by 30W. The yellow got 30W but I added in the small copper alligator clip.

As the chapter states, the 15W was a piece of cake - the green LED was still lit well after 2 minutes of holding the iron to it. I even moved the iron's tip very close to the plastic of the LED but it had no negative effect.

Then I switched over the pencil iron to 30W... and held the tip to the wire. After 40 seconds I was a little worried that maybe I'd selected the Super-LED... or that my pencil iron was defective. But near 1m 30sec, the green LED gave its last performance.

So, I threw away the green LED and replaced it with the yellow... plus I added the little copper clip as seen in one of the photos. I held the 30W iron to it for over 2 minutes, but it just kept on shining.

It's always fun to smoke electronic components - we were promised that in the book's sales sheet, right? The green LED sacrificed itself and I will never forget the lesson it taught me - too much heat can be a bad thing. Use the copper clips whenever possible.

RIP Green LED. You will not be forgotten.

Chapter 3 - Exercise 12

2010-01-27T15:25:00.006-05:00

Finally... soldering! Something that can be dangerous - yeah! (Just kidding - I was wearing my eyeshields like a pro and all about safety.)

So, we get to solder some wires. I've actually done soldering in the past, but it's been a while, so this was a nice way to ease back into it. As you can see from my photos, I dutifully soldered two wires cross-wise... then two more parallel to one another. My joints were perfect if I might add...

I broke down and went and purchased a 15/30 switchable pencil iron... works very well. It's not super heavy but doesn't feel like I'm at risk of shock or burning myself from mishandling. It's also not that fancy, but at this poing I'm not wanting to drop loads of cash on a fancy soldering machine until I get a little more training... then I'll likely donate one or both of my used ones to a high school.

My final task for this exercise was to solder some solid core wire onto the frayed ends of my AC adapter... as you can see from one of the photos, screwing the braided ends into my breaboard really tore them up... so I snipped a red wire and black wire, stripped the ends, and soldered them to the frayed ends of the adapter. I don't have a heat gun (yet) so I went the cheapy route and used my gas grille lighter. I know... I know... not a good way to do it, but I kept the flame away from the wire, away from the tubing, and did quick little waves over the flame. I plugged in the adapter and checked all the voltages I was receiving to make sure I had a good solder joint on both wires. As you can see from my photo, the multimeter probe clips really came in handy here... allowing me to take the photo without juggling one or two probes and trying to hold them to the wires. A good purchase there...

I didn't have a spare power cord available to do the last exercise (shortening a cord)... and I'm hesitant to actually do it... if anyone does do it and takes a few photos, please email me and let me see if I can grab a few of my readers' photos as examples.

Tomorrow... ruining more LEDs. Glad I bought more than 3 or 4...

Dremel

2010-01-27T08:23:00.002-05:00

I mentioned in the previous post that I own a Dremel... if you've been considering purchasing one, check this out... a factory reconditioned one for less than 1/2 the full price - this deal is only for today and, at the time I post this, will last for 16 hours, 35 minutes... and counting.

I've purchased MANY tools from Tooliday.com and can vouch for their service... fast delivery, too.

http://tooliday.com/

Chapter 3 - Shopping List

2010-01-26T14:53:00.005-05:00

We're up to Chapter 3! If you've looked over pages 95 to 104, you're likely overwhelmed at the stuff you need to gather. Don't be - the author does a good job of telling you what he feels are "Essential" versus "Recommended" versus "Optional" - pay attention to that and buy what you can, but some of this stuff is obviously very specialized and I'll likely wait until I need it before I purchase. Most of the stuff on page 99 I don't yet have... some of it can be pricey depending on where you look, but I have such an assortment of tools (including a Dremel) that I'll hold off on these until I discover it's a must have item.

That said, I did already own quite a few things here, so I apologize that I cannot give you a true cost for Chapter 3. Instead, below I'll tell you what I bought (including part numbers), where I bought it, and what I paid... Chapter 3 was another doozy of a bill, but I can already see a lot of this stuff getting used in later chapters and for future projects.

So, I'll start out by saying I already own a 30watt soldering iron, soldering iron stand, and a helping hand. I've had these for a while and cannot remember what I paid for them, but I got the helping hand at ACK for, I think, around $10.00. No memory of cost of iron and stand. I have lots of solder and wire already (page 100).

Okay, here's the list - I had 3 different sources - Mouser (M), Radio Shack Store (RS) and the online RadioShack.com (RSO) - source is listed after the name:

Clip-on meter test leads - RS - $3.49 Part 270-334

Solder pump (bulb) - RS - $4.99 - Part 640-2086

Desoldering wick/braid - RS - $3.99 - Part 640-2090

Heat Shrink Tubing - RS - $3.99 - Part 278-1610

Copper Alligator clips (pack of 10) - RS - $2.99 - Part 270-373

Perforated Board (small) - RS - $1.99 - Part 276-150

Perforated Board (medium) - RS - $1.99 - Part 276-148 (276-147 in book)

Perforated Board (large) - RSO - $x.xx - Part 276-170 (discontinued item)

Project Box - RS - $3.79 - Part 270-1805

Components

Binding Posts (4 in pack) - RS - $3.99 - Part 274-661

Panel-mount jack - size N - RS - $3.29 - Part 274-1583

DC Power plug - size N - RS - $3.29 - Part 274-1573

Boardmount Socket - M - $2.04 - Part 517-929974-01-36-RK

50 Pin Socket - M - $7.87 - Part 801-93-050-10-001000

DPDT pushbutton ON-(ON) - M - $5.85 - Part 633-MB206101-RO

Magnetic Switches - not obtained yet

5mm Red LED (2 per bag) - 2.5 volt - RSO - $1.49 (x3) - Part 276-041

5mm Green LED (2/bag) - 2.5 volt - RSO - $1.49 (x3) - Part 276-022

Signal Diode 1N4001 (2/bag) - RS - $0.99 (x3) - Part 276-1101

100ohm Loudspeaker - M - $3.90 - Part 25SP008

Chapter 2 - Exercise 11 Step 4 Modifications

2010-01-26T14:47:00.003-05:00

A few short videos of my modifications - I switched out various capacitors and resistors. Changing the capacitors seemed to have the largest change... with the resistors, it got hard telling the difference in alarms... many sounded almost identical to previous ones.

Note that the new 4.7 microfarad video is included - listen to it and compare it to the previous video where I used another 4.7 microfarad for C3. (I only had a single 2.2 microfarad for Step 4, so I substituted a 4.7 for C3... now the circuit has 2 of them.)

Getting Organized (aka Saving a Marriage)

2010-01-25T14:09:00.005-05:00

I sat down today to do some more work with Part 4 of Exercise 11... the first photo here shows my little work area. It consist of 1/3 of my wife's beautiful dining room table (yes, it's hers - I just rent space). As you can see, it's getting a little crowded. Okay, messy. I've been putting it off and putting it off, but I had some free time at lunch so I got out a few plastic storage boxes I purchased ($4.00 for one large, $2.00 for three small) and got all my resistors, capacitors, and other components semi-sorted into various compartments. I even used a Sharpie to label each compartment - I was channeling a little Martha Stewart today.

I next moved everything to my office and cleaned off my second desk. Why two desks? One for writing - it's always fairly clean - and the other for stacking stuff and storage. Doesn't everyone have two desks in their office for this kind of thing?

But no more - after about half an hour of going through the junk on Desk 2, I got the surface area cleaned off (and found a book I've been looking for for months... who knew). Now I have a fairly organized workspace to keep plowing forward with the book. I need to go down to my basement workshop - not my garage - that's workshop #2. Doesn't everyone have two workshops these days? Somewhere down there are my soldering irons, helping hands, and a few other gizmos that Chapter 3 requires. I'll get those later.

So, as you can see, I'm all set for Chapter 3 and beyond. I've got a nice organized area to work in, my components and tools are tucked away in the toolbox and storage boxes, and my wife isn't filing divorce papers today. (A side benefit - I won't have to worry about my 3 year old boy getting near a hot soldering iron, either...)

Onward and upward...

Chapter 2 - Exercise 11 Step 4

2010-01-24T17:01:00.004-05:00

This post is for Step 4 (of 4) for Exercise 11.

The goal with this final step is to take what we've learned about the transistors and PUTs and use them to create an oscillating sound similar to a siren. We've already built 95% of the circuit, and the new circuit (on page 91, Figure 2-113) requires removing the LED and adding in a resistor (R10) and a capacitor.

I lacked another 2.2 microfarad capacitor (I used my only one for C1) so I found two possible replacements - a 0.1 microfarad and a 4.7 microfarad. One is less than the required 2.2 and one is more... so my guess was that if the 2.2 microfarad was going to cause a wah-wah-wah alarm sound, that one of the substitutes would likely cause the alarm to sound faster... but which one? Best guess was that it would be the 0.1. Why? Well, one of the tasks in Step 4 was to insert ONLY the R10 resistor... no capacitor. I did this (but forgot to shoot video) and the sound it made was super-fast wup-wup-wup sound... (sorry for getting super technical again in my descriptions - these things cannot be helped).

the 0.1 microfarad cannot hold as large a charge, so it's obviously going to discharge but faster... that was my thinking. The first video will let you see the sound I heard when I plugged it in.

Next, I pulled out the 0.1 and put in the 4.7 microfarad capacitor. The second video will let you see the results of that circuit.

All in all... a very fun exercise. Tomorrow I'm going to do a few of the tweaks on page 92... so I won't be taking this circuit apart just yet... I'll try and make some guesses for what's going to happen when I sub in various parts, but I hope I'm wrong... because it'll make me examine the circuit and figure out why I was wrong. I learn better that way...

Chapter 2 - Exercise 11 Step 3 revisited

2010-01-24T16:11:00.003-05:00

Something just kept bothering me with the circuit I built for Step 3. I read and re-read the section and although I still have some questions (more on that shortly), I knew that the amplification should work and I should be hearing more than the very faint buzzing noise coming from my speaker.

So, I went back to the circuit and then re-examined my breadboard... and there was the problem. Something very simple and easy to overlook. The circuit calls for a 100 ohm resistor in series with the loudspeaker. I made the mistake of putting in a 100k resistor. A factor of 1000! No wonder my loudspeaker was barely audible.

So, below you'll find a video with the newly substituted 100 ohm resistor. That annoying sound coming from my loudspeaker isn't so annoying anymore... I love that sound. It represents another lesson learned - always check your resistors with the multimeter to verify your color-coded selection is correct. As a matter of fact, I should ALWAYS be verifying my resistors with the multimeter against the circuit. On page 86, I went down the list and my brain just saw everything in k-units... R4 470K... R5 33K... R6 27K... R7 100K... oops... wait a minute. That's 100, not 100K.

I'm currently working on Step 4, but Step 3 still has me slightly confused. Back in Exercise 10 on page 80, we saw how a small current entering the Base amplifies the current exiting the Emitter. Okay, I get that. When the transistor is triggered at B, the current is amplified at E.

So, jump to page 91 and Figure 2-109. My first thought before building this circuit was that I'd simply rewire the loudspeaker and have one of its wires connected to the Q4 Emitter... more amps coming out would mean a louder volume, right? But that's not how it's wired up as you can see in Figure 2-109. That speaker wire is connected at the Q4's Collector. Huh? Still, I wired it up as shown in the schematic and it works. I think what I'm missing here is an understanding of how the speaker is oscillating... back in Figure 2-104 on page 86, I see the oscillation from the on-off of the 2N6027... the speaker is getting its voltage/current from the Cathode which turns on and off at a high frequency. But back in Figure 2-109, the speaker is no longer connected to the 2N6027 but instead is getting power directly from the 6V DC positive column (with R7)... so what's causing the speaker to oscillate now? L1 is going into the Collector of Q4 which is oscillating on-off... so is that on-off oscillation what now causes the speaker to buzz? I'm guessing yes, but I'm just not 100% understanding why... feel free to chime in if you have a good explanation.

Chapter 2 - Exercise 11 Step 3

2010-01-22T15:03:00.003-05:00

This post covers Step 3 (of 4) for Exercise 11.

I apologize in advance for the somewhat blurry photos - my camera needs to have a nasty accident so I can get a replacement.

Anyway, now we're up to Step 3. I read through it twice... and I think I need to really read over it again to really understand how this combination of PUT and 2N2222 transitor amplifies the speaker. I think I'm understanding it, but I'm going to have to mull it over for a bit longer.

One of the photos here shows the circuit on page 88 - after I plugged it in, I could definitely hear the mosquito pitch coming from the speaker, but I had to put my ear right up to it.

In the remaining photos, I've added to the circuit and it now looks like the one on page 89. Just an FYI - most of the diagrams (like the one on page 88) will tell you the value for any new components added... but Figure 2-109 is missing the value for R9. You can easily look at Figure 2-110 to find it, but just in case you missed it, it's a 2.2K resistor (written 2k2). It is a Red-Red-Orange band resistor.

After adding the second 2N2222 transistor, the speaker was buzzing but it was really about the same level as with the single 2N222 transistor. No real improvement. Let me know if you hear a bigger improvement - maybe I did something wrong.

I really enjoyed Step 3 - if you're paying attention to the schematics (Fig 2-108 and 2-109), you can really start to see how a circuit begins to build on itself... I'm betting from this experience that I'll be better able to tear down a schematic in the future if I take in it small pieces. Take a look back at Figure 2-103 and think about how much you've learned here - what started as a simple schematic has become much more crowded with components... but not really that much more difficult to understand. I'm very pleased to see that I'm getting this... hope you are, too.

Three weeks ago, if someone had handed me the schematic in Figure 2-110 and told me they'd pay me $1000 to build it, I would have lost out on that payment.

Okay, so tomorrow I'll finish up Chapter 2 with Exercise 11 Part 4. And please, those of you following along and doing these exercises (whether you're behind me, with me, or ahead me), let me know how you're doing and your experiences with the book so far.

Christmas in January!

2010-01-22T14:39:00.002-05:00

I arrived home today to find not 1... not 2... but 3 packages on my doorstop! One from Mouser, one from Radio Shack, and one from All Electronics. (Of course, it really isn't Christmas since I had to pay for all this stuff myself... and I knew it was coming... and none of it was wrapped... but still...)

I'll get these boxes opened and prepare to document the Chapter 3 Shopping List... and I apologize that I haven't yet gotten around to documenting my purchases directly from my local Radio Shack... will try to get to that shortly.