An electronic diversion

Sun 26 July 2009

I've always felt a bit mystified with analog electronics. Sure, I had a few chances to figure it out, but these sorts of things require an experienced guide. When I was a child, I received a Christmas gift of an AM radio kit. It didn't work; my father suggested the crystal diode was broke but we never got it working. He once brought back from a garage sale a kit that's now a collectors item, but it was missing a manual and a few parts. I suppose I can't really fault a guy with an Accounting degree for inadequately explaining what a transistor was without using the term "conductance band", but at the time, the idea of electricity stopping the flow of electricity confused the hell out of me.

So even as I was taking embedded programming courses in college, I was uncomfortable with some of the stuff I would be working with. Sure, all CS grads are required to take a digital logic class, but it didn't cover the basics, like the purpose of ground (science education mostly talks about positive and negative and circuits), or elementary parts like diodes, transistors and resistors. Now that I'm at a point in life that I have a bit of money to spend, I've been looking at intro electronic hobby kits, and watching MIT 6.002 lectures.

The parts

Of the many kits available at local stores and online, one that that caught my eye was a kit on Maker's Shed, a from Sparkle Labs. Most kits are focused on a single project like an AM radio. This kit, however, is described as a "curated selection of parts". It comes with a breadboard and lot of just normal parts, which is great.

neat papercraft organizer

The picture does a better job explaining what's in it than I can. All of the basics are present: resistors, capacitors, diodes, buttons, LEDs, wires. It also comes with potentiometers, transistors and photoresistors. Finally, it comes with a 556 chip (a pair of 555 timers), which turns out to be a real treat. The 556 isn't the sort of thing I would have found in a textbook or in online lectures, but appears to be extremely versatile. And apparently the 555 very high selling IC.

The manual

Interestingly, Sparkle Labs is mainly a Design-with-a-capital-D outfit, judging by their publishedportfolio. This emphasis on visual design shows in their manual, which features lots of stylized 3d renders of circuits alongside traditional circuit diagrams. I'd be very interested to learn how the renders were made, as they're very nice and nearly solve the challenge of translating circuit diagrams to a breadboard.

The manual explains most of the parts included, and offers example circuits to demonstrate their use. For example, when discussing resistors, it mentions industrial color band labeling. The first circuit you build is a handy power supply from a 9V battery down to 5V. Other circuits include a dark detector and light detector. It comes with some transistors, but not enough to build logic gates or simple adders.

The manual ends with a circuit to build a signal generator out of a 556 timer. It's a variant on the Atari Punk Console that uses photodiodes for no reason I can discern. I replaced them with potentiometers (as hinted at), and it works fairly well. I know I've seen other circuits out there and I'm tempted to try them out.

The manual does have some shortcomings though. A few parts included get no mention in the manual, which is a bit puzzling. A couple of diodes are included, presumably for radio, since turning AC current into DC current is a recipe for death in household scenarios. And the section on the 556 comes with a few impressive and fun circuits, but really doesn't explain the function and pinouts in sufficient detail.

From a graphic design perspective, a few of the colors are a bit off. The manual comes with a resistor decoding chart, but doesn't quite match up with the resistors provided. The unprepared may be expecting a far greater contrast between red and brown, and confuse the two. After the manual introduces resistor color coding, 3d renders are done with a generic resistor color banding, which is just mean to lazy people like me.

My final words

Overall, this kit is not a bad deal for a hobbyist. The parts are a cheaper deal for the money than at places like Octoparts and Digikey, and the manual can easily be supplemented by the internet and libraries. If Sparkle Lab's main goal is to corner an "educational" market, the manual might need some revision, or a supplemental website. But my main purpose was to be more comfortable with analog components, in preparation of building a USB powered Sensor Bar for my Wiimote+Ubuntu setup. Mission accomplished.

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