I am working on a project which involves 8 sets of LEDs being controlled by a micro-controller. The micro-controller is also communicating with an IC which is sampling an audio signal. The audio signal comes from either a 3.5mm jack or an onboard bluetooth audio board. In my first version all the components were connected to the same ground seeing as the micro-controller doesn't have an AGND for me to use. Here is a basic schematic of it:
This caused two problems:
The Bluetooth audio board caused a ton of awful noise on the audio signal when a speaker was plugged in to the project. I learned this was caused by the bluetooth sharing a ground with the audio so I planned to use a B0505S DC-DC isolator to fix this. However, this didn't solve the second problem.
Even when the Bluetooth audio wasn't installed i heard noise on the audio line which corresponded to what the LEDs were doing. I was thinking of using an DC-DC isolator again for the Micro-controller and audio IC, but then I realized that if the Micro-controller was isolated from the ground of the buffer and the LED's i don't think the Micro-controller would still be able to control the LEDs.
My question is how can I isolate the audio from the rest of the circuit while still letting the Micro-controller sample the music and also control the LEDs? Would the DC-DC converter still let the micro-controller communicate with the LEDs even though they are on different GND networks? IS there an LC circuit I should use instead to stop any noise on the audio line?