Quote Originally Posted by flotulopex View Post
Hello,
I have to make a kind of keyboard where the buttons are replaced by seven small light beam control (barrières lumineuses - Lichtschranke) having to check a distance of 10 centimeters (is the beam interrupted or not = On/Off).
It's going to look like a light beam grid - four rows and three colons.
I've been looking around in the web for hours and can't make-up my mind (to much information kills the information...) on which system is best to use.
In my opinion, the simplest, cheapest & smallest way to do would be to use common leds with a narrow beam as emitters and, on the other side, as receivers, photodiodes.
Another way would be to use IR leds. The advantage here seems to be that I could "code" the light beam to avoid interferences and make it more reliable. But I never used them up to now so I don't know if I can use the same IR leds as emitters and as receivers and if this solution is better or not.
Does anyone of you had some experience with this he could share?
Thanks a lot for any advice.
I don't know if this is what you're looking for...but I thought what I built was cool...
www.srt.com/~jdgrotte click the LED Touch Sensor link and watch the video (which is really bad quality, someday I'll update it).