Osborne 1 Bluetooth keyboard

[luminescentsimian]

While pondering turning an Osborne 1 case into the sleeper gaming PC and whether to use the original CRT I realized that upgrading the keyboard to Bluetooth would be an easy first step. The Osborne keyboard doesn't have any brains, the cable just exposes the raw keyboard matrix making it super easy to patch it into a micro controller. I had an Adafruit Bluefruit 32u4 laying around which happens to be supported by the QMK keyboard firmware project so after a few of hours of mapping pins and debugging I have a sweet new Bluetooth keyboard! The original casing of the keyboard is so bulky that they keyboard cable and microcontroller comfortably fit inside.

Seen here connected an M1 iMac:

 

[luminescentsimian]

I got my first attempt at PCB designing back from PCBWay and it mostly works! I just submitted a V2 design to be made after realizing the unreliable behavior on one column of keys was because the Feather I'm using has the voltage from the LiPo socket routed there so you can monitor it, but in a keyboard matrix it's just an unwanted pull-up. I also mistakenly selected single-sided on the first batch, which makes soldering things to both sides challenging.


With the right (or is it left?) angled plug it should be able to replace the cable all together. I order the plug bent in the wrong direction so none of the pins match up where they're supposed to go.


The next step, while waiting for the v2 PCBs, is to try cobbling together a Bluetooth receiver using an I2C GPIO breakout and level shifter so the Osborne can still use its keyboard without the wire.

I have 4 extra v1 PCBs if anybody else has a burning desire to upgrade an Osborne keyboard to Bluetooth LE, or any other keyboard with a 2x10 pin connector.