Bluetooth conversion of a Kinesis contour keyboard to a bluetooth keyboard.

Brainstorming

Available approaches

Options	Pros	Cons
USB HID to bluetooth adapter	No modification of the keyboard necessary	USB HID host chips are uncommon and expensive Programming USB HID host may be complicated
PS/2 to bluetooth adapter	Simpler to decode than USB HID Any microcontroller can do it	USB version of keyboard may or may not have PS/2 output
Custom replacement keyboard controller with integrated bluetooth	Getting data directly from button matrix is likely simpler than decoding some other protocol Opportunity to add extra features Likely better battery life	Kinesis keyboards have some advanced programmability - reimplementing that on a custom controller could take some time Requires interfacing with the key matrix directly which either requires special connectors or soldering to the key matrix

Bluetooth module might have HID and audio capabilities
- Use keyboard as audio extender - include a headphone port in keyboard
- Kinesis has a key recognition click speaker built in which can be hard to hear when listening to music, but might still annoy others
  - Overlay key click sound over bluetooth audio signal
USB interface for charging
- disable bluetooth while charging and instead use the USB connection
Saving, editing, and uploading custom keyboard layouts to the keyboard from the computer
- Cross platform application

Development example using Bluegiga WT12
WT12 breakout boards - supposedly open hardware, but I haven't seen the layout files yet
WT12 module
Custom bluetooth IBM Model M using a salvaged bluetooth module from a mini keyboard - salvaged PCB
Custom bluetooth IBM Model M using a salvaged bluetooth module from a mini keyboard - custom PCB
Custom bluetooth HHKB using the WT12