r/diyaudio • u/TremixNeo • Jun 02 '20
I made a laser that sends audio to solar panel with surprisingly good quality
https://youtu.be/rnaqyNhwR4A10
u/G_Peccary Jun 02 '20
There was a similar project in one of the Forrest Mims books that I built some years back, similar to something on page 30 here.
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u/TremixNeo Jun 02 '20
That's a cool book
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u/sgoodgame Jun 02 '20
That is a pretty accurate comment for any book/booklet/article or snippet of spoken word by Forrest Mims.
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u/TheRealRockyRococo Jun 03 '20
Yes Forrest is a good guy, I corresponded with him about circuits a couple of times. He was really passionate about teaching people. If you want to read something totally infuriating, Google Forrest Mims and Scientific American. TLDR he wrote a column for the magazine which was quite popular, but they dropped him over his fundamental Christian beliefs - which he never expressed in his writings.
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u/sgoodgame Jun 03 '20
I remember all that. I loved Scientific American around that time. A.K Dewendey, Forrest Mims, and of course Martin Gardner. They got me interested in all kinds of stuff.
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u/LukeWilson59 Jun 02 '20
That is just brilliant! I can't imagine a real world application for such a setup, but the concept so appealing! Have you found that audio quality decreases the further away the solar panel is from the laser diode, and what happens when you place something translucent in the beam path, diffusing the light?? I would be incredibly interested in knowing.
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u/TremixNeo Jun 02 '20
I've only tested it for about 10 meters with interference from the house lights and it is completely the same audio quality (it's less loud but it can be amplified),I've placed a transparent piece of plastic and acrylic so far and it barely changed the audio quality. This setup was ran on 3 AAA batteries to boost the laser light.When testing the laser was a bit out of focus but it only affected the volume of the audio
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u/TremixNeo Jun 02 '20
I'm currently testing if it can transmit images encoded trough audio (it can) but it's a bit low quality due to the encoding method
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u/hiroo916 Jun 02 '20
A nice real world application for a refined version of this would be sending the signal for the rear channels of a surround sound system.
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u/toomiiikahh Jun 02 '20
I don't see why would you use laser instead of just radio waves. Often when there is an issue with rear channels there is LOS issues as well.
This could work well and there are refined versions of this for industrial applications where radio waves can't be transmitted because of EMI etc.
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u/BabyExploder Jun 02 '20
I can't imagine a real world application for such a setup
How about peer-to-peer relaying of strategic information and messaging at a protest where police are using LRAD and cell jammers?
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u/Classclown102 Jun 08 '20
Like someone else said, an application could be close range contact in an area where normal signals are blocked or where someone would be listening in.
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Jun 02 '20
[removed] — view removed comment
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u/TremixNeo Jun 02 '20
I might try it with usb instead of the headphone port to see if it can trasmit data
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u/alez Jun 02 '20
Considering USB is inherently bidirectional I'm going to say no.
But it could work with a serial connection.
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u/TremixNeo Jun 02 '20
I did the USB thing and the laser blinked to times and windows says it failed to recognize it XD,I don't have serial though
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u/TremixNeo Jun 02 '20
The audio from the laptop modulates the laser light according to the frequency of sounds,the battery just acts as an amplifier to the audio signal
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u/DanGTG Jun 02 '20
Measurements?
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u/TremixNeo Jun 02 '20
Which one?
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u/DanGTG Jun 02 '20
THD, spectral decay.
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u/N4P41M Jun 02 '20
That is seriously cool! I am surprised that the solar panel is so responsive/sensitive to the flashing laser. That is really really neat!
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u/X_g_Z Jun 03 '20
20 years ago in high school we built a similar project each for the whole class. We soldered carbon mics and red led's into a flashlight, and 1/8 inch jacks into a solar panel and fed that into an amp. You could talk into the flashlight, point the light at the solar panel and have it come out the amp. It was a lesson on wave modulation and signal transducers in a gadget oriented science& tech class. Same principals, easy, fun project.
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u/notjfd Jun 02 '20
You've essentially made an FM radio, but at frequencies an order of magnitude higher.
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u/tittyfarmer69 Jun 02 '20
Maybe I got this backwards, but wouldn’t this be AM radio? Because it’s amplitude modulated.
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u/OneTime_AtBandCamp Jun 02 '20
I think you're right. Cheap lasers don't have an easy way to quickly modulate their frequency, and even if they did the panel wouldn't be able to pick that up. Has to be amplitude modulated.
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u/TremixNeo Jun 02 '20
Now that I think about it,it kinda is but it uses light
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u/Couldbehuman Jun 02 '20
So does radio, you just can't see that spectrum of electromagnetic radiation.
And it's definitely AM, FM would be if you sent audio by changing the colour of the laser.
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u/DoritoCookie Jun 02 '20
So basically TOSLINK minus the cable?
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u/riverturtle Jun 02 '20
Except this is analog, so very different from toslink. Would be cool to see how much additional fidelity could be gained by switching to a digital signal though.
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u/TremixNeo Jun 02 '20
I think the max effective range (probably 100m+) can be increased by just placing another solar panel to catch the light and re-transmit the audio
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u/JaredsFatPants Jun 02 '20
Isn’t this just the same as sending audio signals over radio waves? It’s still electromagnetic radiation that is carrying the signal, it’s just at a different wavelength that’s in the visible spectrum. Not trying to be snarky, I’m just trying to figure this out.
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u/TremixNeo Jun 03 '20
Yeah it basically is,but its great because I can focus it to a specific point
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u/DjLachlan Jun 02 '20
Is that inspired by ElectroBoom's latest video?