On covert spy or military missions, yelling to companions is often out of the question, and radios can be picked up on. pigeons can be shot down, the tin cans with string are too conspicuous, fax machines are unweildy, messages written on paper airplanes can be difficult to aim and easy to intercept and bird noises are not always appropriate, as there may or may not be birds in the area.

Take a non-this-incinerates-stuff laser that illuminates an area about the size of a quarter, and make a series of slides to go over the end. different symbols can mean "go back" or "my platoon has been shot" or "there is a horde of huns on elephants behind you". Then, if you can see your contact, from however far away, you can send them a message. receivers could carry table tennis paddle type things for easier veiwing. Morse code could be used. This would be more covert than just using a flashlight, because the laser will only shine on an area the size of a quarter, and the initial light will be harder to see. Not recommended for steamy/smoky locales.
-- schematics, May 12 2004

laser graphics, animation, billboards http://www.n-effect.com/2lasers.html
[dentworth, Oct 05 2004]

IR voice modulated laser transmitter and receivers http://www.amazing1.com/laser2.htm
Reasonably priced, even. [bristolz, Oct 05 2004]

Visible spectrum modulated laser http://www.boreal.c...m?categoryid=271292
[bristolz, Oct 05 2004]

In depth look at 300+Ghz communication band (including light) http://www.n1bug.ne...ser/alc_wa6ejo.html
[bristolz, Oct 05 2004]

//steamy/smoky locales// or nightclubs
-- neilp, May 12 2004


the technology isn't far away from this is it.
-- dentworth, May 12 2004


How big can you make a laser pointer?
-- schematics, May 12 2004


Not so different from a shutter light then, except:
a) the transmitter will have to know *exactly* where the receiver is, and
b) the receiver will have to know *exactly* where the transmitter is.

It'll have to be a not - quite - powerful - enough - to - blind - you laser, too.
-- phoenix, May 12 2004


Yeah, targeting makes this impractical. Although, anything with lasers is fun - sharks with lasers on their heads, for example.
-- normzone, May 12 2004


Just send voice/text/code messages over a modulated IR laser. It'd be invisible. You would have to have a way to aim with some precision, though.
-- bristolz, May 12 2004


<off topic> not really the place to say but Tuck does seem to be exhibiting Troll behaviour.</off topic>

Arent lazers (pedants i know the spelling is laser but i feel Z is under used) used for comunications all ready? i can see a more practical system using a central target and either sending a message to a mobile or a pager.
-- engineer1, May 13 2004


the problem is sending lasers through things without burning holes in them. Unless there was a ridiculously complicated mirror system.

What do you mean by troll? Is he hanging out under bridges and shishkebabing hobbits?
-- schematics, May 13 2004


Stasi used this in the former East Germany for years. Absolute secure transmissions.
-- Klaatu, May 13 2004



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