Derived from my Laser Harp I project and the Laser Autoharp idea I got, this little thing does pretty much the same thing, sans lasers. Using the Teensy LC gives us built in USB MIDI and capacitive touch, so all we need is some electrodes for a strum pad and a simple switch matrix for the keyboard. If you got some tact switches and perf board lying around already, all it will cost you is the price of a Teensy LC. And of course, you can add your own imagination to the mix and get... well you tell me! But as described here you'll get a pocket sized midi controller that is more playable and inspiring than you would suspect.
This is what it does. In the video, it is connected to a Mac running Garageband.
As this project refused to stop occupying my brain, more stuff just kept coming. Now there is a PCB and diy kit for building what I've called the T. Chordstrum. It uses either the tlc strummer firmware on a Teensy LC, or the Teensy 3.2 version of it all, with the addition of built in audio output. I even put a rhythm section in there, with samples from the Keio (Korg) Minipops 7. And it keeps on developing...
This was not a thing on top of my list, but I got curious of the Karplus-Strong implementation in the Teensy Audio Library, and took 30 minutes of my lunch break to put it in my strummer. The Teensy Audio Library requires at least a Teensy 3.2 to work, but I had found a Teensy 3.2 lying around that I had almost forgotten. It even had an audio output jack set up already. With some help from Paul Stoffregen's Touch Guitar code, I had the Teensy 3.2 programmed and working in no time, and the result was not bad at all. Very autoharp sounding :)