HowTo: Electronic design on a budget

You don’t need a dedicated workbench to do electronic design.

After a little thinking, a lot of reading, and fair amount of courage, I took the plunge, placed a Jameco order, and started learning to do electronic design. So far I’ve had a blast — the first time I took a stab at solving a problem and it worked, I knew this was the right thing to do.

One of the challenges of getting this far, though, was figuring out how to assemble the gear I needed on a reasonably cost-effective basis. I spent a good amount of time developing a wishlist, then paring it down and making compromises until I was left with the minimum set of hardware and components I actually need. As it turns out, I chose fairly well… I haven’t hit any roadblocks yet, and I’m halfway through my first project.

It turns out that purchasing an oscilloscope was a wise investment. The ability to view two signals at once with no lag has been a lifesaver… it’s awfully difficult to tell whether your circuit it doing what you expect if you can’t poke around and see it on the screen. That’s lesson number one — a good oscilloscope is a lifesaver. Note that it doesn’t have to be an expensive purchase… a little hunting on eBay or craigslist will net you a number of possibilities in the $150 range. Oscilloscope probes, on the other hand, can be pricey if purchased new… I ordered a pair of 10x probes from Probemaster, but they could probably be found on the used market as well.

The second lesson I learned is that breadboards really are the way to go for prototyping low-speed circuits. Yes, they’re noisy — I’ll probably have to use wirewrap for microcontrollers — but with a few well-placed bypass capacitors, you can build reliable logic circuits without much hassle. While breadboards are inexpensive ($30), power supplies for them are decidedly not — expect to spend $100 on a single-output voltage supply. The investment is worth it (how else are you going to power your circuits?), but it’s one of the few expensive pieces of kit you need to get started.

Prototyping made simple!

Once you’ve got your test equipment and prototyping surface, all that’s left to pick up is individual components. Grab bags are the way to go for things like capacitors and transistors, though you’ll want to choose a component kit when you purchase resistors so that you get a wide assortment of values. Pick up a dozen .01μF and .1μF ceramic disc capacitors as well — you’ll use them all over your circuit, and it’s a lot easier to have a ready pile of them instead of hunting through a grab bag for the right one (speaking from experience here). Expect to spend time learning the resistor and capacitor codes — that’s the only way you’ll be able to tell the values apart! I thought I was hosed when it came to figuring out the transistors (only some are labeled), but my $10 Cen-Tech multimeter has a transistor checker that saved me. (Despite not being a $200 Fluke meter, it works pretty well. A recommended purchase!)

Depending on your project, you’ll also want to purchase a variety of integrated circuits, solid state relays, etc — Google for projects similar to yours, and you’re bound to find suggestions and schematics that will direct you as to what to purchase.

The last thing I had to deal with was what to do with all this stuff. Early experiments ended up taking over the dining room table, and it was clear that that wouldn’t be a sustainable practice when most of my work is done around dinnertime. First things first: the oscilloscope fit nicely on the floor, propped up by its well-designed handle. The power supply seemed destined to float around the table, but since the model I chose was particularly compact, I was able to secure it to the oscilloscope with a bit of velcro and kill two birds with one stone.

Better together!

Consolidating hardware on the floor took care of some of the problem, but I was still left with baggies of components and spare jumper wire spread liberally around my work area. I was about to take out the trash when it occurred to me that the box from one of my orders was just the right size for holding all my parts. I cut the flaps off for use as dividers, and in the spirit of Make, stapled and taped my way to the perfect organizer. A little tray at the top holds jumper wires and loose components, while individual component bags get sorted between a large and small section in the main compartment. The sides of the box were just the right size for a printout of the resistor and capacitor codes — bonus!

A DIY box that does it all.

Throw in a pad of graph paper and a calculator, and you’ve got an area dedicated to electronic design packed into only a few square feet. That’s the kind of organization that’s sure to please mind and spouse alike!