The SDF Public Access UNIX System
Before I knew much about computers --- going as far back as middle school even --- hobby electronics was my main pass--time. Initially many of my projects were tied to the physics of radio transmission, a highlight of which was building a number of Spark-Gap Tesla Coils. This led me to participate in a number of high school science symposiums, once even at the national level.
It wasn't until high school that my interests spanned to modern electronics: things involving integrated circuits or transistors at all, for that matter. Around my freshman year of high school I started cloning electronic synthesizers.
My most memorable project from that period involved cloning the bass drum section of a Roland TR-909 onto a sheet of perf-board. It was an absolute rats nest, but it worked well enough that I was satisfied. At one point during testing, the end of a 500m coil of wire (which I had been using as part of a white noise source) came loose and snagged on something in the circuit. The speakers output immediately changed from a dull repetitive thump to the Beatles' Revolution. That was the first of four times now that I've accidentally made a radio receiver while building a circuit.
My most significant ongoing project is to design a modernized modular synthesizer. This involves designing all the basic parts of a modular system --- VCOs, VCAs, VCFs, ADSRs, etc... --- but with the additional goal of researching the integration of computers into a modular system for the purpose of sequencing.
Occasionally I'll have a reason to build something unrelated to music synthesis. The physics department I work for has prompted this a couple of times. Other times its some odd novelty thing that people keep requesting.
Some of the most interesting things I come across are things that someone wants me to fix. Half-century old pinball machines, Soviet-era synthesizers, lab equipment, etc...