I need to make a wearable PS/2 keyboard (one-off) and would like some input to help me decide between some inconvenient alternatives. The device needs to be small enough to wear comfortably strapped to an arm, have keys with positive action and not too closely spaced so as to require a stylus to depress. I have one candidate already made; a cash-register programming keyboard by TEC, which is just an orthogonal matrix of 5 rows by 12 columns, arranged as QWERTY plus specials, but there seems to be no OTS controller chip that can be easily adapted as all seem to scramble the matrix for whatever reasons (phantom key handling, rollover statistics, etc???).
I have cannibalized a number of 101/102/104 AT PS/2 keyboards and found each to have used a different matrix arrangement; I picked the controller from one with the lowest stated quiescent power consumption and vowed to try and slice and dice the TEC matrix to adapt to it, but the task is daunting.
I also considered making a new keyboard using ALPS micro-pushbutton switches salvaged from a variety of consumer digital equipment (found in everything from mice to laser printer front panels) and wire-wrapping the interconnects on the longish leads to accommodate the salvaged controller.
I don't have PIC dev systems or tools or those for any other lower power MCU for that matter, nor really the time to ramp up for a one- off project like this. Does anyone here have some code for a low power part that permits key assignments to accommodate my ortho matrix? Does anyone happen to have one of a few vendors 'wrist keyboards' that they no longer need?
Thanks,
Michael