I have an esp32 that is driving 3 separate ws2812 led strings.
I also have a DFMP3 player. I take the line out from the player and amplify it.
It seem that the led pwm signal is causing a high pitch noise in the system.
When I disable all the leds output pins, the noise is greatly reduced.
Any suggestions on how to clean up the noise?
Maybe a low pass or high pass filter?
Any links would be appreciated.
I have tried a cap.
Does the noise still happen if the LED signals are running, but not connected to the LEDs?
If not, you could try putting 100 ohm resistors from each output to the LED strings.
A picture or two of your wiring might help...
Yours,
TonyWilk
A running LED strip is one big interference generator and this is to be expected.
There is no golden bullet for this, it might not be fixable. However you can try lots of supply decoupling both on the strip and audio module. You can try different power supplies for both parts. You could try an opto isolator on the sound modules control signals with an isolated power supply.
You could also improve the wiring with the sound module to amplifier, make it short and route away from the LEDs. You could lower the impedance of the input to the amplifier by putting a resistor from the audio input to ground. Find a balance between cutting down the interference and reducing the volume. You could try an AC coupled signal into the audio amplifier, that is a series capacitor.
The noise is there whether the signal pin is plugged in or not.
When I unplug power to the leds, the noise is gone.
I tried two different power sources, a lipo and an AC/DC power supply.
There is a stepdown (not visible behind the lcd display) from the power source to the power distribution pins on the left.
I have two similar setups that are working well. The only difference is I have buck/boost converters on those. I fried the converter on this setup and swapped in a stepdown.
I tried a resister in-line with the LED signal, no help.
I have already messed around with audio gains. The mp3 player has a nice gain/volume adjustment and so does the amp. I found a nice mix between those two on my other setups.
So, next step it to
When I unplug power to the leds, the noise is gone.
That is how you know it is the LEDs causing the interference.
I tried two different power sources, a lipo and an AC/DC power supply.
Why, was that on the list I gave, do you think it would make a difference?
I tried a resister in-line with the LED signal, no help.
But keep in in it is good practice.
I have already messed around with audio gains.
I said impedances not gains.
So, next step it to ....
Ignore the advice you have been given.
Why oh why do you ask for advice and then ignore all of it?
OK fixed it. The issue was the step down. I swapped in a buck boost in its place and problem solved.
