Hi Guys, yeah a completely non mechanical solution could be much better. Currently keyboards use little silicone compressible domes, over copper pads on the pcb.
I have attached an image of what I think you mean, sorry just knocked it up in paint. Is that right?
I have alot of them to do though - 50 in total (i want two octaves), so I want to put them in a matrix. I assume I can put 2 IR leds in series straight from VCC to GND and then those in parralel with the other 25 pairs, then set a resistor in series with them, and then put the phototransistors in a matrix.
I assume the phototransistors pick up an analog reading as opposed to a digital one, so could it even be better to use a pin expander and then connect them to an analog pin?
In terms of the practicalities of mounting them, they obvoisuly (the leds and the photoresistors) need to be facing each other, so can you get right angled smd versions? Also how would I stack them on top of each other?
Thanks guys, I like this electronic solution rather than a mechanical one alot
EDIT:
Like these?
http://www.rapidonline.com/Electronic-Components/Transistor-Darlington-photo-interrupter-68054