This is a quick-n-dirty "Theremin" daemon for use on the RaspberryPi.
It is designed to be used with a couple of these distance sensors:
https://www.adafruit.com/product/4007
Use 'raspi-config' to configure your default sound output (HDMI, 3.5", etc).
This is intended to be run from daemontools or runit. Quick setup as root:
# apt install ruby espeak fluidsynth runit motion netcat
# systemctl stop/disable/mask motion
# gem install -Ng
# ln -s /etc/service /service
# ln -s /path/to/here/theremin /etc/service
# ln -s /path/to/here/motion /etc/motion
# ln -s /path/to/here/fluidsynth /etc/service
For this project, there was an available Pi camera (v2). After enabling it in raspi-config, I also fired up 'motion' with the included configuration file, to capture people using the theremin and to say hello.
# ln -s /path/to/here/motion /etc/service
# (enable motion support in the config file)
It will save images for 2 weeks with the current motion.conf. Season to taste.
This was mounted on a manniquin named "Maude" (the bod), as a goofy/fun interactive instrument.