Getting close!

Getting close!

Yes, I've decided to go ahead and work my way through the new book over at my new blog -- handsonmoreelectronics.blogspot.com. If you've followed along with this blog and wish to see what the new follow-up book by Charles Platt contains, I hope to have you covered. The book is listed as being released on May 29, 2014, but I'm heading to Maker Faire in California this weekend and hoping to get a copy in the Maker Shed while I'm there. (Otherwise, I'll order it online.)

Once I get the book, I plan on spending some time examining the components list and finding the best and cheapest places to order it all.

This will most likely be the last posting about the new book on this old blog as I transition to the new one. So, please join me over at http://handsonmoreelectronics.blogspot.com for more electronics training.

Jim

It's been almost three years since my sign-off (below -- Jan 2011) of for Hands On - Make: Electronics! I cannot tell you how much that book did for my understanding of electronics. Over the last three years, I've soldered up a number of circuits of my own design, built some kits, and figured out a few repairs here and there... all because I have a better understanding of this topic.

And now I've received word that author Charles Platt is planning on releasing an update titled Make: More Electronics in early 2014. I don't have any more details, but you can click on the link and pre-order if you're really anxious to get your hands on it (like me).

My goal with this original blog was to work through all of the projects and document my thoughts, my observations, my mistakes... basically just sharing the experience with others. I've learned over the years that pairing a hands-on education with a careful documentation of my work helps cement what I've learned. I'm a tech writer -- I do articles, books, manuals... my job is to take complex ideas or tasks and to simplify them or at least reduce them to clear, concise statements that can be repeated by others. With this blog, my goal wasn't to rewrite the book -- I just wanted to fill in the gaps (BIG gaps) in my own understanding of electronics and maybe help a few others who might come after me to gather components, catch errors, and basically see someone else doing it first.

And now along comes the follow-up book.

So, the big question I've been pondering today is whether or not to tackle the new book and to blog about it.

I'm going to get the book no matter what. And I'm going to work through it. That much has been decided. But will I blog about it?

I must admit I did enjoy taking the photos and videos of my work and posting it for the world to see. And I must admit it was a lot of work. Time consuming. So I'm going to ponder this for a bit longer. I've got a few months or more before the book is to be released, so I don't have to decide today. But I REALLY want to do it.

So...

I have gone ahead and created a new blog as a holding spot. It will be called Hands On - Make: More Electronics and the URL is handsonmoreelectronics.blogspot.com. Yeah, it's a long URL. Sorry. Just trying to stay with the theme and format of the original. So... that's where any blogging for the new book will occur. (But I'll come back here and post my decision to blog or not.)

If you haven't discovered Make: Electronics -- grab a copy! I've read dozens of electronics books over the years and never found any other book that approaches this level of quality and ease-of-understanding. You'll amaze yourself when you finish the book and ponder where you started and how far you've come!

So, I'm signing off once more... and hopefully will be picking up over at the new blog when the book is released. Come join me!

Final Thoughts

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

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

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?

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

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

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

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

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

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!

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

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

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

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

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

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

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

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

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

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

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

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)

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

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

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

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

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

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

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

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

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

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

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

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.