Instructables

Is it possible to use PWM to send data via a laser?

I am looking into making a laser tag system with an arduino and was wondering how easy it would be to make a laser diode output PWM signals, instead of using an infrared LED. I'm sure this has been considered before, but I couldn't find it anywhere!! Obviously all players would be given protective glasses to wear :)

(on a side note: I was also wondering that if it was possible, could it be used in an RGB laser, to make more than seven colours?)
Thanks in advance :)

AndyGadget3 years ago
 
Certainly possible and HERE is an Instructable giving you a breakdown of what's required.  It uses focussed IR rather than laser, but it is definitely doable.  A good quality laser module would be needed as the cheapo ones are pretty slow to react when you're modulating them, limiting the bandwidth of the signal you're sending.

PWM control is easy with RGB LEDs, PWM is a standard way of doing it to give any colour you want.  If you had a red, green and blue laser doing the same thing I think you would run into the same switching speed problem and you would get flickering, unless you use high-quality lasers designed for this.
rickharris3 years ago
There are already Infrared sensors that decode a carrier stream with data on it - used for IR control. You send numbers so it is easy to allocate a number to an action.

Most microprocessors can cope with this type of event.

For example The Picaxe already has firmware installed to do much of the work. see www.picaxe.com.
Kiteman3 years ago
I would say "yes", since all PWM is at root is a lot of on-off switching, and that is all they use to send data with lasers already.