Step 1: Gather Your Materials
Two Mono Jacks
1 Audio Transformer
1 Solar Resistor
1 Single AA Battery Clip (for reciever)
1 Triple AAA Battery Clip (for laser)
Batteries (1 AA, 3 AAA's)
Some wires and tape
A breadboard is optional, but I chose to use one to save time.
Step 2: Add a Mono jack
Step 3: Add the Transformer
Step 4: Connect the other leads
Step 5: Complete the transmitter
Step 6: Using the Circuit
Step 7: Building the Reciever and Using the device
As stated before, connect an audio source to the first mono jack (the one connected to the laser) and turn the laser on. Connect the other jack to a reciever (such as an amp or the mic. port of your computer) and aim the laser at the solar resistor. The light modulation of the laser are reversed on the reciever and converted back into sound.
Step 8: Alternate construction and Theory
Theory: It may be possible to bounce the laser of glass behind which a conversation is occuring (such as a window) and pick up the sounds on the reciever, but I've yet to test it. Please let me know if anyone has tried this or has a better way to do this.