Chris Miller made the Teensy Beats Shield, an open source, hand held, highly portable, step sequencer.

The inspiration for the project came from Chris’s desire to fill a void in open source handheld musical instruments after finding that most portable audio sequencers are expensive and completely closed sourced.  Someone recommended using Teensy with its digital signal processing (DSP) capabilities – and the Teensy Beats Shield was born.This handheld synth uses a Teensy 3.6 and the SGTL5000 audio codec chip and features a 2.4″ TFT display.  It

Detailed information on the project including information on how to build your own can be found on this HackaDay project page.

Code for the project is available in the teensy-beats GitHub respository.

The bare PCB for the project is available on Tindie.