To make both the LED matrix circuit board and the control board, [Joekutz] carved out isolation paths in copper clad boards using his ... speaker to the Arduino, he hacked the Bluetooth speaker ...

In this case, [AlxDroidDev] is using ... with Arduino. It operates from a 9V battery. The circuit contains an infrared receiver and also a Bluetooth module. This allows [AlxDroidDev] to control ...