[Laser] Simple data/video transmitter.
Thomas Upton
[email protected]
Sat, 11 Jan 2003 21:10:52 -0800
The earphone jack for a common transistor radio is an excellent match for driving either a green, red, or IR LED.
Apparently, the LED transmits on each current pulse of the AC output of the Radio.
Each of these LED's can be modulated at least to 50 MHz.
TV picture and FM sound carrier should be as easy if used in the 0 to 6 MHz range..
Tom Upton AD6N
Applied Communications Services Ltd. wrote:
> I see a great potential for a transmitting data/video via simple, inexpensive laser transmitter for short distances--say up to 1000 ft. A number of companies make such systems --the "Canobeam" by Canon, is one example. However, these systems all cost tens of thousands of dollars. I don't see why it shouldn't be possible to build a system using off the shelf parts, including laser or IR diodes and IR detectors which could mount onto a pair of binoculars or telescope and use a conventional video camera set up in parallel for alignment purposes or even for signal decoding. Does anyone out there have any ideas?
>
> I have experimented with a IR diode transmitter and IR detector on a circuit board, mounted in a piece of 2" plumbing pipe and using IR filters and a convex lens. I transmitted audio using a power line wireless Intercom to FM modulate the signal, and achieved distances of several hundred feet. However, alignment was both difficult and critical. Ofcourse, to run video would require a higher bandwidth. I would think too that digital communications would be more effective than analog.
>
> Ron
>
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