Instructables

The Altoid Box Laser Transmitter!

video The Altoid Box Laser Transmitter!

In this video we teach you how to make an Altoid Box Laser Transmitter! it's an awesome way of transmitting sound using the powers of a laser.

Defractal2 years ago
Great tutorial!

However, I'm really stuck.

I've done everything 6 times over and still I can't get any sound.

I get sound before the transformer, I get sound after the transformer, beyond that - nada!

I've eliminated the solar cell and replaced it with another one, still nothing.

I've replaced the laser with an LED and it works - Kind of!
It's intermittent like it's 'buffering'.
The laser doesn't work at all.

Any ideas please anyone?
Thanks very much
INSTEAD I PUT A MIC AND IT WORKED
ac1D4 years ago
If I have everything needed on hand, exept the red laser, can I use a cheap 1mw green laser instead?
HM-Innovations (author)  ac1D4 years ago
yes you can, you can even use an LED but you have to be pretty close to the cell in order to pick up the signal.
:D no unless u focus it with 4 mirrors witch inhand i did...........i got a 50FT range and it also transmitted ont meh car radio..... :D
O_o IT WORKS WITH A LED LIGHT 2 but i has 2 put 2 mirrors makin it shine like, LIKE a laser.....DO NOT TRY...havin probs still.......XxshadowxX14 y dosent the shack in murrieta,hemet and oma linda have those even though THERE ALMOST THE SIZE OF WALMART........
How would I go about making this so I can use a wall outlet instead of batteries? Would I be able to just use a low output transformer AC adaptor ?
HM-Innovations (author)  RiddleOfSphinx3 years ago
Yes you can, just use a low output ac adaptor
sachrekar3 years ago
Is it possible to use this for cymatics? To direct sound with surgical precision?
HM-Innovations (author)  sachrekar3 years ago
yes
i have been interested in this circuit for quite a while, although for a different purpose.

the audio transformer is modulating the signal for your input into pulses of light that are picked up by the phototransistor, solar cell, light dependent resistor, whatever it is that your using.

radio's are super simple to make with an audio amplifier IC, a coil of wire with one end cut and attached to a "slider" to change resonance for use with a fixed capacitor or a normal coil with the use of a variable capacitor.
by doing that, you can dial into an AM station then solder the "slider" or glue the variable capacitor in place so you know at which frequency the coil resonates at.
then using this circuit, lose the laser, bump up the battery to a 9 volt, and, and send the ground to the antenna side of the resonator, and the positive to the other end and you should have an AM (amplitude modulation) radio transmitter right???

i still have yet to try it.
HM-Innovations (author)  XxShadowxX144 years ago

That is correct, we made a small radio transmitter for a class one time and thats pretty much how it worked. (the way you described it)

out of curiosity i picked up an audio transformer (I work at radioshack  [=  )
and gave it a try. it was super weird, i had two matching crystals i was going to use, way easier than trying to make two coils with identical frequencies and ran the transmitter audio through the transformer, and the reciever through an amplified speaker. it worked, but at a VERY short range, and the strange part was, when i took the crystal out of the transmitters breadboard, the audio could still be heard as loud and clear as it did with the crystal. im so confused!.
You work at radioshack!?
HM-Innovations (author)  XxShadowxX144 years ago
Yea that transformer is actually weird, we had an instance where instead of hooking up the laser we were grabing onto the transformer and as long as we made contact with the 'former and were close to the receiver we could actually hear the sound. that was pretty cool but we had to be like right next to the receiver for it to work.
That was Inductance. A magnetic field created by the transformer.
Transformers are basically a coil wrapped around a stack of metal plates charged with ac or dc current, some are called step downs and other step ups.

But they have many other uses.
AndyGadget4 years ago
Very neat, and the audio sounds surprisingly good.
Have you done any testing to see the frequency response of the setup?
HM-Innovations (author)  AndyGadget4 years ago

No not yet but that might be good to try