Wiring a set of photointerrupters(ir switch, beam breaker) onto a computer keyboard key

[usv]

I'm working in a life science laboratory and need to determine the time of event when an animal has broken the photo beam of a photointerrupter or beam breaker.

I would like wire the output of this sensor to a computer keyboard since I already have a logging program detecting key toggles on the computer.

Can anyone give me an advice if it's possible or not?

Thanks for your help! 

[PBear]

Hi usv,

I'm going to lean on the advise that this is going to be hard, if not impossible. You'll have to know your sensors output charecteristics and build external circuitry to interface this to a keyboard input (whether this be USB or PS2), which could quickly become daunting.

You do have a decent amount of options, whether that be using a DAQ car or possibly interfacing through your sound card input. You could create an op-amp comparisson circuit that sends a DC voltage when the beam breaks.

[AnalogKid2DigitalMan]

A Rube-Golberg approach would be to use the beam interrupter to active a solenoid momentarily to depress a key on the keyboard.

-AK2DM

[Henrik_Volkers]

The classical approach is to (ab)use the good old legacy printer port to get 8 input lines. Maybe it will also work with a USB2LPT device .... (when I did it, my PC had a printer port, and now I have PXI systems :-)) ) 

That will all involve some circuitry (mainly to protect the PC, mainly optocoupler). 

For less than 100 bugs a simple USB DIO will do the job, however it is possible to use an old keyboard as an 100+ input and 3 output device, if you browse the web and you should find some DIY solutions  (nice topic for an high school project).

Message Edited by Henrik Volkers on 09-30-2008 10:13 AM

[AnalogKid2DigitalMan]

Henrik "For less than 100 bugs a simple USB DIO will do the job" What kind of bugs do you suggest? :) -AK2DM