Reading this week’s ATtiny-themed builds, [Thomas] was reminded one of his coolest builds. His midi808 project used an ATtiny2313 to sync a vintage Roland 808 drum machine to his Logic workstation.

Even though MIDI had been around for a few years when 808s were being made, the CPU in the 808 isn’t exactly up to the task of handling MIDI. Instead, the 808 used an interface known as DIN Sync that was designed to keep 808s, 707s, and 303s in time with each other. MIDI to DIN Sync boxes do did exist, but even the auxiliary equipment to use an 808 is getting hard to find.

The build takes a MIDI signal and passes it through an opto-isolator per the MIDI spec. The microcontroller reads the MIDI signal and passes it out through the DIN Sync port. The DIN Sync protocol is only 24 pulses per quarter note output with TTL voltages, and the project code is easy enough to follow. It’s a nice build for one of the greatest drum machines ever made. Listen to a track [Thomas] made with his new setup after the break.

This is a shot of the largest PCB in the TR-909, which contains all of the console knobs.

In this closeup of the board that hold the 16 step buttons, you can clearly see the TC5565P-15 chip in the center, which is a generic memory chip. It is probably one of the most replaceable parts in the whole machine. A few other chips specific to the TR-909 can also be seen.

We would have liked to see a little more description of what each part does. That said, it’s great to see the inside of this machine, which would have been a tall order given the rarity of it and the value a typical owner attaches to it. If you’re interested in getting a feel of how a TR-909 sounds, check out ReBirth RB-338: it’s a retired program that modeled the analog hardware to emulate the functions and sounds of a TR-909, as well its sister drum machine, the TR-808, and the eminent TB-303.

[via Matrixsynth]