Voltage drop in analog input when led blinking (Rpi/arduino/pd)

Dear all,

I’m new on this forum so I hope I won’t ask something already posted or something like that.

I’m working with an arduino nano, a raspberry pi and pure data to make a sound effects controller. I use pots as analog inputs, leds as digital outputs and toggle switches as digital inputs.

Here’s my problem : when my pd controlled led is blinking I get unstable values from my analog inputs corresponding to voltage drops when the led is high. Since my project is a sound effects controller, I can’t have unstable values getting into my pure data’s patch.

Attached a simplified circuit of how I’ve set up my stuff.

If anyone would have advices, solutions or explanations, that would be really great !

Thanks