Wat

This pcb is an audio multiplexer, meaning it can switch three analog inputs into one analog output.

Why

Sometimes you just need more inputs. And this is how you do it.

How

The BD3491 does all the audio switching. It combines one 6 input switch and an equalizer into a simple package. The STM32 configures the BD3491 to switch to the specified inputs based on pressed buttons or software control.