Cheap, simple Arduino synth doubles as a variety of drones : r/synthdiy
Build an Auduino Step Sequencer - learn.sparkfun.com
synth | PlanetArduino
14 synthesizer Projects - Arduino Project Hub
GitHub - maltman23/ArduTouch: ==> ARDUTOUCH KITS ARE AVAILABLE at CornfieldElectronics.com <== ArduTouch is an Arduino-compatible music synthesizer kit with a built-in touch keyboard, and with built-in speaker/amplifier. Build it, and it works!
Projects | Computer coding for kids and teens | Raspberry Pi
Arduino Uno Clone: Kit Build and PWM Synth Test - YouTube