In final form, a Bluetooth module and Arduino Pro Micro are stuffed inside the stereo along with a DPDT relay to switch the I2C bus. An external button is used to trigger the Arduino to switch to ...

Connect the device, launch the terminal monitor in the Arduino IDE, then give it your desired settings. The sketch will poll the Bluetooth module to see what speed it is set to run at.

Power can be applied as 3.3V via pins, 5V via its USB-C connector or 6 – 21V via pins. Arduino has not included active power consumption on its data sheet but, according to the uBlox datasheet, module ...