Controlled Burning Dot on White Wall from 15ft

[jbeuckm]

First Post! I searched a bit and haven't found the answer, so apologies if it has been answered.

My question is two parts:

1. What diode/lens setup would easily scorch a dot on white paint from 12-15ft in a few seconds or less?

2. If I want to control the burn, should I PWM the diode or just turn it on for one cycle of measured time? Does power cycle wear out a laser diode?

Thanks,
Joe

 

[ElektroFreak]

You'll want at least a 2-5 Watt IR diode, these are available in 9mm, c-mount, and to-3 packages. Do an ebay search for IR laser diodes. To get scorching temps at that distance will require you to focus the beam on that point, so adjustable optics will be necessary as well.

It is possible to build a laser so powerful that it will scorch white material at that distance without focusing, but the cost and practicality will make it very difficult.

As for a lens setup you'll probably need to be creative, but I can tell you that a member here, heruursciences, sells some optics that you could use. You can find his main thread here.

For control, PWM could work but the simplest solution is to use a duty-cycle like you said. There is some debate as to whether or not power cycling harms diodes, but generally it is accepted that it does not as long as the power never exceeds the diode's rating.

Check the links in my signature as well, particularly Sam's Laser FAQ. There is useful info in there that will help you out along the way.

 

[Ash]

Or you could buy a 2w 808nm focus adjustable labby for less than $200:
2W 808nm focus adjustable module£­>808nm,780nm,980nm laser£­>Laser&lighting products£­>www.0-like.com

 

[jbeuckm]

Thanks ElektroFreak - very helpful stuff!

I've sent a PM to heruursciences but I know he has been having problems with PM on here. Do you know his ebay name that I could email him there?

 

[ElektroFreak]

^It used to be heruursciences, but he changed it.. I'm not sure what to. I'll PM his email address to you..