Idea about a signal carrying wave

[KhaledOsmani]

Hello,

I have seen a set of two circuits: transmitter/receiver that transmit audio signal from one to other using a laser

Is this idea theoretically real? How could a laser beam carries a sound wave to the destination circuit that has some sort of light detecting sensor, that once the laser is projected upon it, it outputs via a speaker the same sound wave generated on the transmitter circuit


I cannot post the DIY at the moment, but if there any similar circuits please let me know



Thanks

 

[ads-ee]

Hello,

I have seen a set of two circuits: transmitter/receiver that transmit audio signal from one to other using a laser

Is this idea theoretically real? How could a laser beam carries a sound wave to the destination circuit that has some sort of light detecting sensor, that once the laser is projected upon it, it outputs via a speaker the same sound wave generated on the transmitter circuit

I cannot post the DIY at the moment, but if there any similar circuits please let me know

Thanks

Of course this is possible.
1. digitize the audio using an ADC
2. encode the output data for transmission
3. modulate the laser output with the data you encoded
4. de-modulatate data at receiver
5. decode the data from the receiver
6. use an DAC to convert the signal back to audio

https://www.instructables.com/id/Send-Music-over-a-Laser-Beam/

- - - Updated - - -

The instructables DIY doesn't seem to digitize anything so it's probably just using the audio to directly modulate the laser. I'm used to the idea of digitizing things and adding extra encoding for error correction over bad channels, hence the more complicated approach. ;-)

 

[KhaledOsmani]

Blessed is your brain

 

[Audioguru]

The Instructable simply amplitude modulates (AM) the brightness of the laser beam. Then a photo-transistor detects the AM modulation and outputs the audio.
But since it is an Instructable, it is wrong and WILL NOT WORK because the photo-transistor is not powered and has no load. The photo-transistor must be connected to a mic input that is powered and loaded for an electret mic.

 

[KhaledOsmani]

Can you please tell how come a light physically carries the signal? How this transformation from wired signal to a wireless signal takes place? As in definition of laser it is a inner reflection of electron to a certain speed before it push out, how could forcing a signal to "ride" it can theoretically takes place

 

[ads-ee]

Amplitude modulation - means in this case the strength of the laser output.

You know the "internet" uses fiber optic links to transmit data around.