This is an old revision of the document!
A BLE (Bluetooth Low Energy) Chorder using the Adafruit Feather 32u4 Bluefruit LE
This board has the LiPo charger and BLE transceiver built in, so all that is required is attaching the keys, an on/off switch, plugging in the battery and programming it (over a standard micro usb cable).
Here is the link to the github source:
Download the Latest BLE Build
Thanks to Charles Chen for this version!