Now available on Tindie: RetroConnector USB Interface.
Connect a USB keyboard to your Apple //e.
Open Source hardware and software, programmable with Arduino. Designed to fit into an open slot in the //e, but doesn't require to be in a slot - all power and connections come from the keyboard ribbon cable.
https://www.tindie.com/products/option8/retroconnector-keyboard-interface-for-apple-iie/
quick video demo:
https://www.youtube.com/watch?v=BpDztgL1Iwc