The BEEBoyBLE app navigates and connects to nearby Bluetooth BLE devices and sends 1 byte of ASCII characters mapped to that button.

Arduino programming allows you to conveniently transfer various commands if you define different mapped actions in advance.

[Default mapping - Button name: Function definition (mapping character)]
L go: left forward (B) / Go: forward (U) / R go:
L Ro: Left turn (L) / B go: Push (F) / R Ro: Right turn (R)
LED: LED flashing (A) / Back: Reverse (D) / Buzz: Buzzer (S)
F1, F2, F3: Custom (M / N / O)