I'm currently building a Bluetooth speaker using a TDA7492 based Bluetooth audio board.
I also want to incorporate an audio visualiser as per this project:
The Arduino is sharing a power supply with the Bluetooth board and as a result I believe suffering from a ground loop.
The Audio visualiser requires the negative side of the audio outputs be connected to ground. I assume the Arduino requires this to measure the audio output.
I can get the the audio visualiser working if I use a separate power supply (usb) but my project requires that the Arduino and audio board share a power supply.
Is there some way of letting the Arduino and the audio board share a ground on the power supply and separate the audio output negative for the Arduino to measure?