This is a simple passive sonar microcontroller. Contraty to an active sonar, this does not send out pings.
It visualizes detected sounds on a screen using gradient colors to indicate the direction of the sound sources, relative to the sonar's orientation. The dimmer the color the further away the target is from the sonar.
It also includes filtering capabilities, allowing it to suppress certain detected sounds, such as the engine noise from your own vessel.
