Ableton Link enables iOS and desktop app users to hop on to the same network and jam in sync with others using multiple devices running Link-enabled software. The technology keeps these devices in time, so you can forget the hassle of setting up and focus on actually playing music.
Up until now, it has not been available for hardware enthusiasts — developer Vincenzo Pacella’s inexpensive, open source project is changing that. The pink-0 consists of a custom shield for the Raspberry Pi Zero, which uses software scripts to create an Ableton Link-compatible gadget with outputs that send clock and reset signals to your Eurorack analog gear. It connects to a network over Wi-Fi or Ethernet (via an adapter).
The pink-o will keep in time with Ableton Live, as well as any of the other apps that now have Link support wirelessly, including Maschine, Traktor, Serato DJ, Reason, Launchpad for iOS, and Blocs Wave.
The basic idea is to enable the audio output on the Zero, as explained in this nice article, and then to use Ableton Link for what it’s best at: synchronizing an audio buffer. The clock and reset signals are in fact rendered respectively as the left and right channel, therefore the RC filters are required to filter off the 50Mhz PWM component and “isolate” the audio signal. The NPN transistors then provide level shifting to 0–5 volts and clean up the edges of the clock and reset pulses.
The software part mainly consists of a daemon, which uses portaudio and Ableton Link to generate the clock and reset signals. All the signals to/from the shield are handled using wiringPI.
Although the pink-0 is not for sale, you can find Pacella’s schematics and code here.