If you’ve searched around for “How to build a laser communicator“, you probably stumbled across several examples that use the RadioShack Audio Output Transformer, Catalog #: 273-1380. I’ve built one and it works great, but it’s roughly $3 just for the transformer and finding these things elsewhere is nearly impossible. They also add unnecessary bulk to the transmitter and we can build it using much cheaper components!
Laser Communicator WITH Transformer
The transformer version works great. The only problem is that the transformers are a bit pricy and you’re very limited on where you can buy them. You might try searching for “Audio Coupling Transformer“, which essentially all that it is used for here is for the purpose of isolation and a 1:1 small audio transformer would work for that.
Here’s a few links that feature this transformer version:
MAKE Magazine – http://makezine.com/projects/simple-laser-communicator/
Their Youtube Video for this can be found at http://www.youtube.com/watch?v=HKRPfa66_po
Sci-toys.com – http://sci-toys.com/scitoys/scitoys/light/light.html#laser_communicator
RK2Production Youtube Tutorial – http://www.youtube.com/watch?v=jvrXXQGXYg4
Transmitting Audio Wirelessly Through Light – http://treehouseprojects.ca/audiolight/
- 3.5mm Stereo Heaphone Plug
- Audio Output Transformer [RadioShack.com] [See Notes For Additional Options]
- 4.5V 3AA Battery Holder [w/o switch] [w/ on/off switch]
- Laser Module OR Laser Pointer
- 3 x AA Batteries (Buy them locally)
- Wire (Cat 5/6 cable works great)
“Why did I not use a laser pointer?”
Because the laser modules are essentially the laser pointer stripped down to just what we need for this project. There’s no trying to keep the button pressed down, etc. AND the laser is focusable, making it a better option for longer range transmitting. Oh, and it costs much less.
However, if you want to use a laser pointer, you can find cheap ones in a variety of places. The ones I found have both an LED light and laser pointer from WalMart for approx. $2.49 by the checkout registers. I then found some at the local Dollar Tree for $1, which were a bit smaller than the ones I found at WalMart.