I've been between gigs for the past few weeks and, unlike every other time in my life when I've been between gigs (except one), this time I decided to take a little bit of me time. I decided to pick something I was not good at but wanted to be good at, and work on it for a while. I chose electronics design.
I used to play around with electronics a lot as a kid. I knew them well enough to read a schematic, to build sometimes pretty complicated things, and to have a basic understanding of what I'd need to change about a circuit to make it do different things (like, say, changing the gain on a simple amplifier circuit). At some point, my parents gave me a hand-me-down university computer and I just kind of left electronics behind a little. This past month I've tried to catch myself back up to where I'd like to have gotten with it.
I never really studied electronics, except during college strictly within the digital realm. Digital electronics are either off or on. They only understand 0's and 1's. Serial. Parallel. You end up using an awful lot of NAND and NOR logic gates. I already felt like I knew just about enough about digital electronics. I've had absolutely no problem with even some very complex Arduino projects the past year, so I'd reviewed digital as much as I needed to. It was time to finally actually understand analog electronics.
Literally the only bits of analog electronics design I'd mastered were the kinds of skills you'd need to build a radio, or that came up in the written exam the FCC gives you if you want a ham radio license (my call letters, for those who care, are KF4SOO). I'd had an idea last year, to sell a modular analog synthesizer in pieces as kits, the kind you could buy one at a time and put together yourself if you wanted, the kind that moms and dads wishing to impart their love of electronics and music to their kids could assemble as a fun little project. I felt like it was a really cool idea, and would even be well suited to be crowd-funded on Kickstarter or somewhere. I didn't have the knowledge or skills that I needed to complete such an ambitious project, though, so it sat on the back burner for a few months.
From a business perspective all I'd worked out was that the system needed to be inexpensive, with discrete modules, each serving a simple purpose, that were easy to wrap one's head around. I wanted to design simple things like a MIDI-controlled oscillator, some simple filters, a mixer, and amplifying stages for use with other equipment. I imagined a whole ecosystem of related musical instruments that could all be hooked into each other and work together.
So, I spent the past month studying, practicing, and building, and today I am sending off the order for the first batch of parts for early prototypes of one part of the system I've been designing. Along the same lines as the whole analog synth system, I've designed a simple 8-note sequencer, similar in purpose to a Roland TB-303 synthesizer but far simpler in functionality. It features tempo adjustment from 60 to 180bpm, and two oscillators that work in concert to generate a super-wide variety of square-wave tones. The eight steps of the sequencer route power through 8 different controls for the second oscillator, so the first oscillator can be thought of as an octave control. Printed circuit boards for my design are on their way here (got the shipping notification earlier today), and I'll be assembling them into cigar box enclosures as soon as I have all the necessary parts. I'll be blogging more about the design and the assembly of the first units soon, with detailed photographs.
The circuit at the centre of the design is Forrest Mimms's "Stepped Tone Generator" (a.k.a. the "Atari Punk Console"), a widely-known circuit that uses the classic 555 timer IC to make funky stepped tones. Anyways, I'm back to it. Rock on, space cadets.