433MHz RF modules audio transmission

by QC

Posted on Sat, May 02, 2020 - 01:24:43 AM

433MHz Audio Schematics

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Motivation

 

The other day I've watched a video from great scott, in which he is talking about transmitting audio over cheap 433MHz modules: https://www.youtube.com/watch?v=PKowvbnIxso

He comes to the conclusion that the highest possible frequency for his PWM is ~5kHz, which sounded not reallly plausible to me. Therefore I've ordered such modules off ebay and set them up on my own:

Screenshot of the video.

   

Video

          

To document this process, I've uploaded a video explaining myself to youtube:  https://youtu.be/wH0-SI4t4D0

Schematics

The schematics for this project are actually quite simple. It basically decouples and shifts the audio input, mixes it with a triangle wave to get a PWM and then transmits this. The receiver side uses an buffer amplifier for driving an LC filter which filters some of the unwanted noise, before hooking it to the 3.5mm jack:

Schematics.

Sound

There is a sound test in the video, but if there is interest, I can record and upload a test file on how good you can work with this, just write me a short message or leave a comment below.

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