Hi,

Anyone know of a LASER pointer or similar device that is capable of turning on and off at a rate of 10kHz plus. The LASER beam will be subject to PWM for the purposes of audio transmission through free space.

Turns out e-bay LASER's aren't up to the task.

Rueffy.

 

I don't know of any diode lasers part numbers although I'm sure lasers that do what you want exist - have you tried buying them from places that publish accurate datasheets? I'd expect that information to be included.

Were you using just a laser diode or an ebay laser module that included a bunch of drive electronics? You really want to drive the diode directly.

Don't dismiss the option of running the laser CW and modulating with an LCD, moving mirror, etc

 

I believe the lasers themselves are fast enough, it's the DRIVER circuits that are slow.
Maybe you could replace the driver circuit.

 

I believe the lasers themselves are fast enough, it's the DRIVER circuits that are slow.
Maybe you could replace the driver circuit.

To OP:

What you are looking for is a laser with TTL input.
The driver you have has only two wires . You need one with three.
A third yellow wire to which you will feed your pwm .
Try searching ebay for something like : Laser module with TTL , or Laser TTL
Or constant current driver with TTL , there are plenty available...

If you want a laser pointer to do this then you will have to install the driver yourself .
I doubt you will find (i'm sure you won't) a laser pointer with TTL , but a whole module(driver+laserdiode+ optics) you can find plenty. Then you can pick out a cylindrical housing for the module and your 10khz circuitry+switch+battery.

 

Ebay laser modules are VERY cheap and come as just the laser diode and focuser lens/brass housing, and two wires.

You can modulate them just like a LED, at 10kHz or 100kHz no problem.

 

Laser pointer have a simple discrete driver in it for just on/off. There are integrated driver with allow you to modulate. Standard driver, like the iC-WJ (http://www.ichaus.biz/product/iC-WJ iC-WJZ ) can easly reach 300kHz or higher. You can try to modify a laser pointer or another alternative is to buy a complete laser module with TTL-input for modulation, like you can find at Roithner: http://www.roithner-laser.com/lasermodules/laser_modules405.html .

 

Sorry I never got back to you guys on this thread, a LASER dot diode module was the way to go, I tried a LASER diode but it came with the collimating lens separate, a real pain to try and position correctly, the dot module was all ready to go, just needed to design a driver circuit around it.

Thank you to all those that helped contribute to the development of my circuit. The project is now fully functional and I've made a video as part of my presentation to a class, the video shows the system in operation with a full description of signal flow etc.

http://www.youtube.com/watch?v=CCAkpJ-jG6A

rueffy.