The hardware

 

The main processing in the EEG-synth is done on a Raspberry Pi, an inexpensive microcomputer (under $40). However, you can use and develop the EEGsynth on any PC, Mac or Linux computer. The electrophysiological recordings are done using the affordable open-source hardware of the OpenBCI project. However, the EEGsynth can also interface with state-of-the-art commercial scientific equipment. We are able to do this by using the FieldTrip realtime buffer which supports many hardware systems. If you are interested in developing your own code, make sure to familiarize yourself with the FieldTrip realtime buffer.

To control analogue and digital synthesizers, the EEGsynth can send out CV/gate, MIDI, as well as Open Sound Control (OSC) signals, and is thereby extremely flexible and able to interface with most sound as well as visual performance equipment. In our projects we focus mainly on controlling analogue modular synthesizers, which makes it important to be able to generate CV/gate signals. We started with generating MIDI commands, that and translating them into CV/gate through dedicated hardware modules. Robert Oostenveld also designed and build our own USB-to-CV/gate converter, which uses an Arduino and some ICs (some soldering and drilling required). The first USB-to-CV/gate version had one CV/gate channel and was able to output up to approximately 5 Volt. The second one is an improved four channels version that can output from 0 to 10 Volt. Both can be controlled with EEGsynth’s outputcvgate module. The schematics have been made with the EAGLE PCB design software. Also included below is the bill of materials (BOM) with links to component vendors . These have been mainly found on Ebay, but you can also get them elsewhere as well. Also included is a link with more description and code for testing.

Single channel USB-to-CV/Gate convertor

2015-10-03 16.35.52

 

 

Four channel USB-to-CV/Gate convertor

2015-10-18 13.11.43