Thursday, June 5, 2014

Off-Topic: Two Small Electronics Projects

I should have Experiment 3 finished up tomorrow -- fingers crossed. And while I'm waiting on components to arrive, I decided to tackle a couple of small electronics projects. One is for my son (age 7) and the other is one I'm hoping to finish before my electronics camp begins on June 17.

The Solar Marble Machine from
The first project is a little baggie of parts I purchased at Maker Faire for my oldest boy from -- it's the Solar Powered Marble Machine. In a nutshell, a small motor drives a geared wheel (with holes for small ball bearings) round and round... ball bearings come out one at a time from the top, roll down the spiral ramp, and feed back into the geared wheel at the bottom. A small solar panel provides the juice so the machine can operate indefinitely when placed in direct sunlight.

Today my son and I sat down to build it. Let's just say the part of the project that involved the laser-cut wood pieces went smoothly... the small circuit board that needed soldering up did not. The little circuit board didn't have holes... instead, you soldered components to small copper pads. I'm not a great solderer to begin with, and this thing was just pure frustrating. The pads are tiny... very close together, and I probably should have purchased a tinier tip for my soldering rig. Instead, I dove in and quickly discovered how hard it is to solder small lead wires on capacitors and transistors to pads while trying to keep the tiny solder beads from touching. I failed often. Lots of desolder wick was used, but in the end I either burnt out a component due to too much heat from the iron OR I created a short somewhere that wasn't easily visible to the eye. Whatever the case, there was no power going to the motor. My son was not happy. Neither was I.

Failed to get the circuit board to provide power.

But you know what? Make: Electronics gave me enough hands-on practice building circuits and soldering and adding in switches and such... I just knew I could fix this thing. It might not run on solar power, but it was going to run on something! That's the thing -- I think a lot of people might get frustrated and toss the entire thing out, but all that was needed was tossing out the little circuit board and finding a way to provide power to the motor. Why not just add a single 1.5v battery and a small switch to the mix and give my son the ability to turn the Marble Machine on and off?

And that's what I did. It doesn't look as perfect as the solar powered version, but my version has character. (And it'll run on a cloudy day). It took me about 15 minutes to find a tiny switch, a small 1xAA battery holder, and my wire strippers. Ten minutes after that, I called out to my son to come take a look at the operational Marble Machine. It made his day, and his smile made mine.

After getting the Marble Machine working, I was pretty fired up and feeling confident!

One of the things I learned (and learned WELL) from my time working through the experiments in Make: Electronics was the value of wiring up and testing a circuit before implementing a more permanent solution such as putting everything in a case. It's so much easier to pull out what you believe to be a faulty transistor or LED from a breadboard than to try and cut one out of a soldered circuit that's tucked tightly into a small project box.

Over the years, I've been guilty of buying small electronics projects and jumping right in with the soldering iron. I don't know my ratio of successes to failures, but I'd be willing to bet that I ruined a lot of projects by just slapping everything together before testing all the components. I've made a promise to myself to avoid that kind of thing, and so that's why today I spent a good hour or so wiring up the Kaleidoscope Goggles' components with a breadboard and jumper wire.

The wiring isn't complicated, but imagine if one of the components was bad to begin with? The Trinket is $8, and each of the NeoPixel LED Rings is $10. It seemed wise to spend the time to just see if everything would work as desired.

Test wiring wasn't fun. I should probably investigate some better options to replace the small copper clips and jumper wires I used to connect all the components, but it did work. The frustration mainly came from wires popping out from under the clips. The Tinker (circuit board) also isn't designed to insert into a breadboard, so I angled it a bit so I could insert jumper wires through three specific holes (GND, Pwr, and Pin#0). The rest of the components -- battery box and two NeoPixel rings were a mix of jumper wire with clip and jumper wires sharing connectivity on the breadboard.

Yeah, it's not pretty. Not pretty at all. I tested each of the rings separately before connecting them together and powering them up. As the video below shows, the rings worked perfectly. I'll have to tinker with the program to change the brightness, speed, and color choices (it's all randomized right now) but that's got to be a cakewalk compared to test wiring these finicky items.

I hope you don't mind me interrupting the coverage of the Make: More Electronics experiments... these experiments are going to go a little slow based on my examination of later chapters. But hopefully with these side projects you'll see that I'm trying to take what I learn from the books and apply them elsewhere. I've got plenty of ideas for some new circuits of my own as I work through the book, so hopefully you'll enjoy them scattered in here and there as we move through the book.

[Note: Getting that tiny Trinket controller operational was another hour of troubleshooting -- the Adafruit forums were EXTREMELY helpful in helping me narrow down the problem I was having getting it to control the rings. This little device is amazing, and I've got a dozen ideas of my own for how I could use it. Check out the details here. I have no affiliation with Adafruit -- just really like many of their projects]

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