Friday, April 30, 2010

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 (
10DIODES $7.86

(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.

Wednesday, April 28, 2010

ePub digital edition - Update

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.

Monday, April 26, 2010

Chapter 5 - Exercise 27

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.

Friday, April 23, 2010

Chapter 5 - Exercise 26

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

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.

Thursday, April 22, 2010

Chapter 5 - Exercise 25

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

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:

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 - AllElectronics didn't seem to have any alternative to it - if anyone finds an alternate source, let me know.)

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)

Tuesday, April 20, 2010

Chapter 5 - Work Area and Misc

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 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.

Wednesday, April 14, 2010

Chapter 5 - Shopping List

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 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

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

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

Tuesday, April 13, 2010

Components Pack 2

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.

Monday, April 12, 2010

Chapter 24 - Exercise 23 Complete

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.

Friday, April 9, 2010

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

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.