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ArcticMyst Security by Avery

Fun laser expariment! TRansmit sound w lasers!






Gazoo

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Very good find..I was talking to a friend of mine the other night about this, but I had no idea it would be this easy.
 

Things

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ya i have seen this too, very cool! but it is very sensitive! ;) it is very fun to do though! see how far you can transmit sound with it! :D
 

Benm

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This method is obviously very sensitive to ambient light and atmospheric fading of the light path (at really big distances, that is).

I would be much better to work with a modulated carrier, but not having a practical purpose for it i never tried to build it.
 
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Sep 11, 2007
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I have a kit that came with my (sadly, non-working) HeNe laser, that is set up for doing this same kind of experiment... Of course DIY instructions are always cool!

I'm actually looking forward to setting up an experiment with this, but I need to create a new power supply for the Laser, or else find a refurbished one at a decent price. I suppose it would be possibly with a plain 5mw red (the HeNe is only .95mw) but the HeNe has the screw-on tips and such that would make the whole process much easier.
 

Benm

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You'll try modulating a HeNe laser yourself? I'm sure it can be done, but think of the stuff you will have to mess with. Power supplies for those things strike at kilovolts - i'd rather mess with low voltage electronics ;)
 
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BenM: The laser already has the modulation circuitry, right down to the 3.5mm jack on the back. It's an ex- science lab laser that was used for demonstration/instruction. It also included two "experiment boards where you can do various things with the modulated light, including routing it to a speaker via a DAC.

I've been reading about the power supplies on sam's faq, and I'm still undecided on build vs. buy... I think it would definitely be an interesting project to try building, but if I can pick up a ready-made one for $40 or something it would be hard to pass up.

-jb
 
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Sep 25, 2007
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I have a friend who used I think a SP106 HeNe (about 3 feet long) for this.
He stuck a piezoelectric disc between one of the rear mirror's alignent screw and its mounting plate.
Then he realigned the laser to compensate for the added disc's thickness, he fed the audio to this disc and it caused the rear mirror to modulate the intensity of the beam. The beam hit a solar cell fed into an audio amplifier and this worked pretty good!

I had a heathkit HeNe in the past and I beleive it had a modulation input on it also
 

Benm

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Oic... i though you were planning on building a power supply that included modulation on the output.
 
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Sep 25, 2007
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Hi guys!

Does anybody have a detailed instructions on how to make a portable laser projector ?

Thanks

Rene
 
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Aug 16, 2007
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Instead of transmitting sound with a laser, why not do the reverse and listen to conversations with a laser. I think they have a device which can listen to conversations by converting the vibrations on the window reflecting a laser beam.

Might be a little hard to achieve without some serious and stable stuff though. Any ideas?
 

Benm

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I've seen some video's of that, and i'm sure it would be doable yourself. Problem is that you must be at a normal angle from the window you're eavesdropping on (or use to locations putting the laser in one, and receiving the reflection in anohter).

Better not use visible lasers though - wouldn't be very stealthy at all ;)
 
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Jan 1, 2008
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if i have this kind of thing actually can be verry fun walkin at the street u see sexy lady ..you r shy to speak w/ her :D
 

roSSco

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Dec 5, 2007
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xarylx said:
Instead of transmitting sound with a laser, why not do the reverse and listen to conversations with a laser. I think they have a device which can listen to conversations by converting the vibrations on the window reflecting a laser beam.

Might be a little hard to achieve without some serious and stable stuff though. Any ideas?
http://www.freeinfosociety.com/electronics/schemview.php?id=2147
secret.gif
 
Joined
Dec 22, 2007
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listening in isnt all that hard. and you dont even have to be at a perfect angle either- if you can put a right angle prism on a window you can hit it from any angle. they sell a kit in the back of pop science for this same thing.
 




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