Spying with a Laser

Want to spy on people with a laser? Dating back to the 1940s, this oldie but goody is super simple to pull off! We can easily send audio over a laser and into a basic light-sensitive receiver.

The method itself was developed by Léon Theremin in the 1940's and originally used a simple IR beam invisible to the naked eye. Of course, we have made this much simpler at a slight cost of audio quality.

The possibilities are endless for this simple device, you could bounce the laser off a window and hear what is going on inside, you can hook an mp3 player into the power circuit and stream your music out as well.

All the items shown here are easily obtained at an electronic's store such as Radio Shack or Frys and won't cost much more than a few bucks if you get a cheap laser.

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[HouseholdHacker]

@zybeel If you feel overwhelmed by the instructions, just watch it a couple times. It is a very basic circuit here and the receiver itself is just two wires on a input jack. The best way to learn is trial and error.

[clansapngad]

What about a giant super laser point it to the moon to hear the aliens.

[kaipakta]

I used a higher quality solar panel/laser pointer, it works BEAUTIFULLY! I love your videos!

[Tian]

something tells me his neighbors watched this video

[saaaaaakkkkkkkkkkeee]

"have you ever wanted to spy on your neighbors with just a beam of light?" O>O....O<O...
no?

[utubefrog]

its funny, when you were transmitting clear audio from your phone from 3 feet away directly into your solar cell, you couldn't make any of it out, but miraculously you were able to "Bounce" light off of neighbors window, receive it in your solar cell and get clear audio, how wonderful. Oh by the way, where is your audio amplifier, is it that big thing because you need audio amplifier connected to your solar cell to amplify the vibration before it can be converted back into sound. I take it that you're not an engineering student

[AntHraXUltranblet]

"Honey, the geek across the street is spying on us again!" -His neighbors

[coondogtheman]

For the laser audio transmitter you need a transformer in line with the laser pointer and the audio will sound much clearer. Use a low power solar cell if you're using a high gain amp. I used one from an old solar garden light and it was almost overpowering my amp.

[garrettmitchell]

That's a really good way to get audio for a horror movie

[fivefourteen]

Lesbian neighbors + Good quality = YES

[HouseholdHacker]

@bilyisbored92 This is a very old (by my standards) trick. But it was too awesome to not let everyone know about. There are a multitude of ways to do it as well. There is another similar method by Simon Quellen that he posted up on scitoys some years ago. A bit more involved but it will produce a better quality output.

[HYBECTIVE]

Wouldn't this work better with a blue laser; since their is deeper uv rays. For example I noticed that the blue laser shot at a solar panel gives it much more power, and basically means that the signal with the blue laser would be more clear and powerful?!!

[raredude]

ya the ladies coming over, you got to leave

[Nskyline]

the carpet you were working on hurt my eyes

[yeoscore]

You should make an all day live stream with that in a window... Of course it'll only work at night though...

[SriTejaChilakapati]

I think 90% of his subscribers are secret agents!!!! LOL!!!!

[patrefkorwa]

i was wondering if you power up the electret microphone and laser device (transmitter). so electret microphone picks up sounds surrounding and send it to receiver.

[tinfoilhat]

It sounds like you're trying to summon Satan xDDD

[GeezerRay]

School project in 1967 was to send music over a laser beam from about a mile away. Back then it was a gas laser, of course.

[geckofrog]

If I made the first circuit with a USB cable instead of the batteries, and an LED light instead of the laser, would the light flash slightly to music played through the audio jack?
Also, what is a MONO audio jack? Does it have to be mono?