The Arduino Nano PS/2 Keyboard Synth is an inexpensive DIY synth.

Control is via a PS/2 Keyboard Synth with drum and bass sequences, programmed on Arduino Nano.

Sound generation is by the S1 Wavetable MIDI Waveblaster Compatible Synth, a € 29,95 Waveblaster compatible synth module based on the SAM2195 chip..

Here’s an example with better audio:

Details on the project are available at Hackaday.