Intro: Laser Audio Transceiver With LM386 Audio Amp
*Note* This project is done by students from Singapore Polytechnic. Tools and components were provided by our FYP supervisor Teo Shin Jen.
Laser Audio Transceiver
In this project I'll show you how to make a laser audio transceiver, a device that will allow you to take any sound source, transmit it over a laser beam, receive it at the other end, and play it at your speakers.
With some soldering and cheap electrical components, you can create one of the coolest, yet simplest electronics project that will be fun for the newbie and advanced hobbyist alike.
Shopping list :
1 A cheap laser pointer
1 Light Dependent Resistor or Photocell
2 5-15 Volt power supply (4AA or 1 9v battery each)
2 Battery clip/holder for battery
1 Sound source with an output jack (eg. MP3 player, phone)
1 3.5mm audio-in jack(or any suitable audio-in jack)
1 3.5mm audio-out jack(or any suitable audio-out jack)
2 LM386 audio amp IC
2 IC socket 8 pin (for mounting IC)
2 Capacitor, 10 micro Farad
2 Capacitor, 0.1 micro Farad
2 Resistor, 10K ohm
2 Resistor, 1K ohm
3 Potentiometer, 10k ohm
1 Copper strip board
2 Plastic casing (or any box to house your circuit)
Copper wires for circuitry
Step 1: Design & Concept
The transmitter will consist of laser pointer, batteries, LM386 audio amp, 10 micro farad capacitor, 0.1 micro farad capacitor, 10k ohm resistor, 10k ohm potentiometer and audio-in jack. The transmitter will convert and amplify the audio into an electrical current to be transmitted over the laser, making the intensity of the light be directly affected by the intensity of the audio. This process is called amplitude modulation.
The receiver essentially works the opposite way, with the laser replaced by an audio-out jack and audio-in jack replaced by the light dependent resistor(LDR). The LDR will vary the amount of current (via resistance) depending on the intensity of the light it receives. The current will be input into the LM386 which amplifies the electrical current and converts it back into audio.