How to easily transmit sound using a laser

How to easily transmit sound using a laser

The laser beam is very well modulated by sound vibrations. It is enough to connect the module from the laser pointer to the output of the low-frequency amplifier and you will have a ready-made audio signal transmitter in the light range. Any solar battery is capable of receiving and converting light into sound. Even without an amplifier, it is enough to connect a high-impedance headphone to its output and you will hear the sound transmitted through the light.

Will need


  • 2 digital amplifiers -
  • Laser module 5 mW -
  • Solar battery -
  • 2 dynamic heads.
  • 2 sets of 6 V batteries.

A set of modules for transmitting sound using a laser beam

Scheme


Circuit for transmitting sound using a laser beam

The presented circuit can be divided into two parts: on the left is the receiver, on the right is the transmitter. The sound from the smartphone is sent to a low purity amplifier. Next it goes to the laser diode. The oscillations modulate the laser beam, which is directed towards the solar cell. From it the signal goes to another amplifier. It is amplified and sent to the dynamic heads.

Assembling a circuit for transmitting sound using a laser beam


We solder the laser module to the output of one of the amplifier channels.
Solder the laser module to the amplifier

We take a wire to connect to the smartphone.
connecting to a smartphone

Solder to the amplifier input.
Solder to the amplifier input

We connect power to the amplifier from a set of batteries.
Connect power to the amplifier

The sound transmitter is ready. Let's move on to making the receiver. We connect the input channel with a jumper and solder the output from the solar battery to them.
We connect the input channel with a jumper

Solder the wires to the speakers.
Solder the wires to the speakers

Solder the wires from the speakers to the amplifier.
Solder the wires from the speakers to the amplifier

Test in action


Turn on playback on your smartphone. We direct the laser point at the solar battery.
We direct the laser point at the solar battery

As a result, clear, distinct sound is heard in the dynamic drivers. See the video below for a closer look.
At night, this installation can transmit sound over a distance of up to a kilometer. Naturally, everything is limited by the power of the laser module.

Watch the video


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Comments (2)
  1. Alexander
    #1 Alexander Guests 10 November 2022 20:49
    0
    I came across your article on sound transmission using a laser. Please tell me, a laser is still a dangerous thing, you never know if something falls and your vision gets affected by it. So, is it possible to replace the laser with an LED, install focusing lenses in front of it and transmit sound in the same way? I really liked this idea.
    1. Yuri_
      #2 Yuri_ Visitors November 11, 2022 01:01
      0
      Laser radiation does not pose any particular hazard to vision.
      That is, if from the usual LED get a beam of the same diameter and the same power as from a laser, then the danger from it will be exactly the same as from a laser.