Laser data transmit: how to

[xnihilo]

Hello,

I would need to substitute an IR data transfer system (IR led and IR receiver-demodulator at 40KHz) with a laser transfer because using an IR led and a lens is not accurate, the beam spreads as range increases.
I'm working on a lasergame equipment and I would need accuracy.

Data is a byte, in my current project, the signal is PWM at 40KHz. I'm using a PIC16F690.

I have absolutely no idea of what I should use as a receiver for the laser beam, should I use a photodiode/phototransistor? Is there some information available somewhere? Looking in Google didn't bring me any good results.

Any clue would by welcome.

Thanks.

[mackrackit]

I have a laser fence that uses a photo diode/photo transistor. The only problem is shielding from ambient light. But I am not modulating either, just a make / break setup. Modulating should help.

[xnihilo]

I have a laser fence that uses a photo diode/photo transistor. The only problem is shielding from ambient light. But I am not modulating either, just a make / break setup. Modulating should help.

Hello,

Yes, this is a good start.
I may use a LDR. The receptor should be optimized for the wavelength of the laser. I could not find any relevant info on the web, quite surprising...
It should be fairly simple to replace an IR led / IR receiver by the laser equivalent...

[mackrackit]

I used the laser diode from a laser pointer. The wave length on the label was 660-680nm.

[RFEFX]

Ok... STOP !

Before you burn your retina... please note that all lasers emit harmful IR radiation and should not be used in this application.

sounds to me that you are not using the correct Lens for the IR LED and Receiver.

Please read this thread http://www.lasertagparts.com/mtoptics.htm

for you to actually transmit data with a real laser you would need an infrared laser which is Extremely dangerous because of the concentrated amount of invisible IR radiation.

Please read this topic on Why IR is bad (www.wickedlasers.com/laser-tech/WhyisIRbad.html)