Guacenspiel
This Raspberry Pi python program reads touches from a capacitive touch sensor module and converts them into MIDI signals. It also acts as a 4-track looping MIDI sequencer.
To configure for your setup, copy config.py.example to config.py and edit as necessary.
NOTE: This program will not make music on its own; something will have to listen for the generated MIDI signals and produce the corresponding sounds. In my case I'm using FluidSynth on the same Pi and doing everything through ALSA.
Here are the commands I used on a fresh Raspbian Jessie Lite installation to get everything setup:
Run sudo raspi-config and enable I2C.
To get the guac code and its dependencies:
sudo apt-get install build-essential python-dev python-smbus python-pip git python-pygame
git clone https://github.com/adafruit/Adafruit_Python_MPR121.git
cd Adafruit_Python_MPR121/
sudo python setup.py install
cd
git clone https://github.com/lendot/guac.git
cd guac/
cp config.py.example config.py
Edit config.py as needed.
To install and run fluidsynth:
sudo apt-get install fluidsynth
sudo fluidsynth -s -a alsa -m alsa_seq /usr/share/sounds/sf2/FluidR3_GM.sf2
In another window I use aconnect to connect the output device guac uses to the input device for FluidSynth:
pi@guacenspiel:~ $ sudo apt-get install alsa-utils
pi@guacenspiel:~ $ cd guac/
pi@guacenspiel:~/guac $ aconnect -l
client 0: 'System' [type=kernel]
0 'Timer '
1 'Announce '
client 14: 'Midi Through' [type=kernel]
0 'Midi Through Port-0'
client 128: 'FLUID Synth (751)' [type=user]
0 'Synth input port (751:0)'
pi@guacenspiel:~/guac $ aconnect 14:0 128:0
pi@guacenspiel:~/guac $ aconnect -l
client 0: 'System' [type=kernel]
0 'Timer '
1 'Announce '
client 14: 'Midi Through' [type=kernel]
0 'Midi Through Port-0'
Connecting To: 128:0
client 128: 'FLUID Synth (751)' [type=user]
0 'Synth input port (751:0)'
Connected From: 14:0
In config.py set midi_device=0 and run sudo python guac.py