The LED ring expansion board contains two powerful front-facing white LEDs and 12 bottom-facing RGB individually addressable LEDs (it uses the same LEDs as used in the neopixel products by AdaFruit).

The board is designed to be installed as the last board on the bottom of the Crazyflie 2.0. It does not have pass-throw holes for the expansion port connector.

The RGB LEDs are connected in in series and can be addressed individually. When a new color is sent to U1, the U1 color is sent to U2, the U2 to U3 and so on. So sending 12 colors to U1 will update the full ring. Drivers for the ring exists in the Crazyflie 2.0 firmware.