Separating Ground Planes

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?

Send us a wiring diagram and a link to the data sheets of the parts.

Wiring diagram

Audio board used:

Instr_CSR8635_BT_w_pic (1).pdf (394 KB)

Thanks. As I understand the problem occurs when the audio board is involved, connected to the same power source. I hoped for a wiring showing how You connected the lot.
Data sheet of the audio board is highly wanted....

Did You check the need for current? Do those two boards draw too much current, more than the supply delivers and therefore the problem?

I don't see any audio ground, only L- and R-.Likely they should not be connected to each other.

Railroader:
Thanks. As I understand the problem occurs when the audio board is involved, connected to the same power source. I hoped for a wiring showing how You connected the lot.
Data sheet of the audio board is highly wanted…

Did You check the need for current? Do those two boards draw too much current, more than the supply delivers and therefore the problem?

I can’t find a data sheet for the audio board.

Ok. Let's wait for somebody having experience of this board.

Here is a video demonstrating the issue I currently have.

The power supply I'm using is a 240v AC to 24v DC 1A inverter. The audio board max amps is 3A. I'm using a voltage reducing buck to turn the voltage down to 9v for the Arduino. I believe 2A is recommended for the Arduino?

So it looks like my supply isn't giving enough amps. Cod this be causing the issue in the video?

Can you confirm the 9v power supply has no ripple ?

Can you try a different buck converter ?

First questions why You use 9 volt and that connection? Why not go for 5 volt and connect it to the UNO 5 volt?

That 1 Amp might be too little.

Do You feed 24 volt to the audio board?

2 Amps for an UNO is a lot. An UNO alone consumes some hundred milliamps as I recall. If LEDs are added, add the current of those LEDs.

The audio board can take 12-24v

The idea of the 9v input was to ensure a reliable 5v output from the Arduino.

Ok. However I recommend a direct, stabilised +5 volt directly to the controller 5 volt pin. Using the UNO onboard 5 volt converter gives You almost no possibility to spend current on the outputs. One LED, maybe 2, then that not cooled 5 volt converter is overloaded.

larryd:
Can you confirm the 9v power supply has no ripple ?

Can you try a different buck converter ?

I have tried two different buck converters and had the same problem.

I will measure the supply for ripple

Check at both the input & output of the buck converter.

nathrouty:
The idea of the 9v input was to ensure a reliable 5v output from the Arduino.

Which is of course, dead wrong!

While some people do suggest using the on-board regulator to minimise ripple on the 5 V, this regulator has little or no heatsink and can only supply perhaps 100 mA before overheating and (hopefully reversibly,) shutting down or at least failing to regulate. Its very existence is a rather nasty trap for naïve players!

You have shown a MAX7219 module attached to this 5 V - with all of 4 digits lit, this would draw at least 160 mA on its own and generate a considerable amount of ripple in any case, so any benefit of the series regulator in providing a smooth supply is immediately lost.

At the very least you require two capacitors - 100 µF and 100 nF - across AREF.

I have tried the setup with the buck turned down to supply 5v, but still had the same issue.