A variation on the Midi synthesizer from this post: https://reactivemusic.net/?p=4960
The synthesizer was built in PureData (Pd extended) using the visual interface on a MacBook. Then the pd file was run in command line mode on the r-pi. The sound card is a Griffin i-Mic, running at 22.5 Khz sample rate. Although there’s no reason why you couldn’t use the builtin DAC on the r-pi.
The r-pi is connected via the ethernet port to a wi-fi network which receives Osc (Open Sound Control) messages from an iPod running touch-Osc. The network connection could have been made using a USB wifi adapter.
All together the cost of this arrangement (less the iPod) would be less than $50. The software is all open source. The huge financial barriers to working with music synthesis and signal processing, that have been associated with these fields for years, simply don’t exist anymore.
Alternative ways of controlling the synth – if a wiFi router is not available, include:
- USB keyboard (usually free)
- USB Midi Keyboard ($25)
- switches or dials via the GPIO pins (spare parts)
- direct ethernet connection to another device.
Notes:
Pd file: tkzic/rpi/pd/piSynth1_OSC.pd
recieve port is 8000 – and it uses page 1 of the simple touchOSC template
pd-extended -nogui -noadc piSynth1_Osc.pd
Note: there is some special code to prevent seg faults when you go from page 2 to page 1 of the touchOSC template
Here’s a great tutorial on using OSC with Pure Data
http://en.flossmanuals.net/pure-data/network-data/osc/
