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Author Topic: Wanna' communicate, and broadcast, with light? It can be done!  (Read 1093 times)

Offline ThaDood

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I've experimented with IR and white light LED's. Even thought of this as a station STL. However, this is Line-Of-Sight, so snow fall, heavy rain, even birds, will block this.   http://www.modulatedlight.org/optical_comms/optical_index.html     and    https://sites.google.com/site/g3xbmqrp3/optical      All neat, and legal to do.
I must be getting older. Now, when I watch a 007 James Bond flick, Ms. Moneypenny is even looking more attractive.

Offline KaySeeks

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Re: Wanna' communicate, and broadcast, with light? It can be done!
« Reply #1 on: June 11, 2022, 0146 UTC »
When I was a young lad (maybe 12 years old), I had a 100-in-1 electronic project kit and got a bright idea.

They had a project in the accompanying book that was a simple audio amplifier. I used that amplifier to drive the LED in the kit and used the small speaker in the kit as the microphone input to the amplifier. It worked well enough and it was fun to watch the LED brightness go up and down with my voice. Later I hooked up the solar cell (or maybe the photodiode? I forget) as a detector to a second amplifier and a second speaker and I could sort of hear myself on the other speaker. It probably had the audio quality of Alexander Graham Bell's call to "Watson, come quickly. I need you." but it worked.

Thus I made a transmitter and receiver. I figured out later that this was essentially AM.

I showed it my brother but he didn't care about the details. All he wanted was a bloody QSL card. Bastard.
Just somebody with a radio, a computer and a pair of headphones...

Offline redhat

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Re: Wanna' communicate, and broadcast, with light? It can be done!
« Reply #2 on: June 11, 2022, 0431 UTC »
Complements of Max M Carter, who has a cool radio hobby website as well;

Music on a light beam http://maxmcarter.com/lasrstuf/laserexperiments.html

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Offline Charlie_Dont_Surf

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Re: Wanna' communicate, and broadcast, with light? It can be done!
« Reply #3 on: June 30, 2022, 0137 UTC »
Thus I made a transmitter and receiver.

I did something similar. A darkened room helped (lower "QRN"  ;D )
I don't STRETCH the truth.

"Every minute I spend in this room, my signal gets weaker.
Every minute Charlie squats in the bush, his signal gets stronger."

Offline Pigmeat

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Re: Wanna' communicate, and broadcast, with light? It can be done!
« Reply #4 on: July 01, 2022, 2313 UTC »
 I picked up a little Forrest Mims project book at Radio Shack around 30 years ago that went into detail on building your own LED transmitters and receivers. He preferred red LED's.

 

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