Summary

...inspired by a post on a 3D printer user group on facebook, unfortunately i cant find the original anymore...

This is a keychain holder keyboard that utilizes guitar jacks to plug in the keychains.
the guitar plugs have a resistance soldered accross the terminals, so each keychain can be encoded. An arduino nano with built in bluetooth hc-05 is used to read the encoding of the keys and display it on an rgb led.
The keyboard can take two keychains, altough you can modify it to your needs.
The thing is drawn in FreeCAD 0.18.1 and the Arduino is programmed in Arduino 1.8.5

The electronics are assembled in free form under the arduino. Unfortunately i didnt have proper rgb leds in my build so i had to use seperate 3mm leds. I'll update that.

You can find the code and the schematic on my github: https://github.com/stonetronics/guitarJackKeyboard