* Low and critical battery alarms (when battery monitoring enabled)
* Arm/disarm tones (and warning beeps while armed)
* Notification of calibration complete status
* TX-AUX operated beeping - useful for locating your aircraft after a crash
* Failsafe status
* Flight mode change
* Rate profile change (via TX-AUX switch)
If the arm/disarm is via the control stick, holding the stick in the disarm position will sound a repeating tone. This can be used as a lost-model locator.
There is a special arming tone used if a GPS fix has been attained, and there's a "ready" tone sounded after a GPS fix has been attained (only happens once). The tone sounded via the TX-AUX-switch will count out the number of satellites (if GPS fix).
The CLI command `play_sound` is useful for demonstrating the buzzer tones. Repeatedly entering the command will play the various tones in turn. Entering the command with a numeric-index parameter will play the associated tone.
Available buzzer tones include the following:
RX_LOST_LANDING Beeps SOS when armed and TX is turned off or signal lost (autolanding/autodisarm)
RX_LOST Beeps when TX is turned off or signal lost (repeat until TX is okay)
DISARMING Beep when disarming the board
ARMING Beep when arming the board
ARMING_GPS_FIX Beep a special tone when arming the board and GPS has fix
BAT_CRIT_LOW Longer warning beeps when battery is critically low (repeats)
BAT_LOW Warning beeps when battery is getting low (repeats)
RX_SET Beeps when aux channel is set for beep or beep sequence how many satellites has found if GPS enabled
DISARM_REPEAT Beeps sounded while stick held in disarm position
Connect a supported buzzer directly to the BUZZ pins. Observe polarity. Also if you are working with flight controller outside of a craft, on a bench for example, you need to supply 5 volts and ground to one of the ESC connections or the buzzer will not function.