INAV Firmware Buzzer

I. Introduction

The INAV flight controller system supports buzzer notification functionality, mainly used in the following scenarios:

1. Power alarms (requires battery monitoring enabled)

• Low battery warning
• Critical low battery alarm

2. Flight status notifications

• Arm/disarm sounds (including in-flight warning tones)
• Calibration complete notification
• Failsafe status indication

3. Flight mode change notifications

• Flight mode changes
• Rate profile switching (controlled via TX-AUX switch)

4. Aircraft locating function

• Continuous beep can be triggered via TX-AUX switch (for locating after crashes)
• If using sticks for arming/disarming, holding the stick in the disarm position will trigger a repeating tone (can be used for locating)

The flight controller board immediately emits three beeps after power-on, indicating successful gyroscope calibration. The INAV system automatically performs gyroscope calibration on every startup.

Important Notes:

• During calibration, the aircraft must remain stationary until the three beeps are heard. If the aircraft is moved significantly at this time, the system will detect interference and automatically restart the calibration (the three beeps will be delayed), until the aircraft is stationary again.
• If the aircraft is only slightly moved, it may result in inaccurate calibration data, which can affect flight stability. In this case, recalibration can be performed by:
  • Manually triggering calibration using RC transmitter stick commands
  • Directly restarting the flight controller board

When the aircraft successfully obtains GPS lock, the system will emit a special arming tone and play a "ready" tone once after the first successful fix. If the buzzer is triggered via the TX-AUX switch, the number of beeps will indicate the current number of satellites (requires GPS lock).

You can test various notification sounds using the CLI command line tool: repeatedly entering the play_sound command will cycle through all notification sounds.
Note: All flight controller platforms equipped with a buzzer interface have buzzer notifications enabled by default.

II. Setting up the Buzzer

The buzzer can be controlled using CLI commands in INAV Configurator.

List current usage:

Important

beepr

List all buzzer settings:

Important

beeper list

After running the command, you will get:

Available:  RUNTIME_CALIBRATION  HW_FAILURE  RX_LOST  RX_LOST_LANDING  DISARMING  ARMING  ARMING_GPS_FIX  BAT_CRIT_LOW
BAT_LOW  GPS_STATUS  RX_SET  ACTION_SUCCESS  ACTION_FAIL  READY_BEEP  MULTI_BEEPS  DISARM_REPEAT  ARMED  SYSTEM_INIT
ON_USB LAUNCH_MODE  CAM_CONNECTION_OPEN  CAM_CONNECTION_CLOSED  ALL  PREFERED

The CLI command syntax is similar to the feature command—add a minus sign (-) before the feature name to disable it.

Disable buzzer notifications when powered via USB:

Important

beeper -ON_USB

To disable all features, use:

Important

beeper -ALL

To save current settings to preferences:

Important

beeper PREFERED
save

To restore settings from preferences:

Important

beeper -PREFERED
save

III. Buzzer Tone Sequences

The buzzer is controlled using square wave sequences:

• Odd positions = ring duration (unit: ms/10)
• Even positions = silent duration (unit: ms/10)

ID	Name	Tone Sequence (unit: ×10ms)	Description
0	GYRO_CALIBRATED	20,10,20,10,20,10	Gyroscope calibration complete
1	RX_LOST_LANDING	10,10,...70	SOS Morse code (signal lost + landing)
2	RX_LOST	50,50	Signal lost alarm
3	DISARMING	15,5,15,5	Disarm notification
4	ARMING	30,5,5,5	Arming in progress
5	ARMING_GPS_FIX	5,5,...30	Arming + GPS fix acquired
6	BAT_CRIT_LOW	50,2	Critical low battery
7	BAT_LOW	25,50	Low battery warning
8	NULL	Multiple beeps	Satellite status, etc.
9	RX_SET	10,10	Receiver setup complete
10	ACC_CALIBRATION	5,5,5,5	Accelerometer calibration complete
11	ACC_CALIBRATION_FAIL	20,15,35,5	Accelerometer calibration failed
12	READY_BEEP	Multiple tones	GPS fix acquired, ready to fly
13	NULL	Multiple beeps	Variable beeps (confirmation, satellite count)
14	DISARM_REPEAT	0,100,10	Disarm stick held notification
15	ARMED	0,245,10,5	Armed notification

Supported Buzzer Types

• Active Buzzer: Supported by most flight controllers, only requires power to sound. Controlled by flight controller GPIO.
• Passive Buzzer: Requires PWM or analog signal control, not supported by most flight controllers, may produce "clicking" sounds or no sound. Some like the Matek F765-WSE come with a passive buzzer with special support.

Known Compatible Buzzer Models:

• Hcm1205x Miniature Buzzer 5V
• 5V Electromagnetic Active Buzzer (continuous sound)
• Radio Shack model 273-074 (3-16V) 70dB Piezo Buzzer
• MultiComp MCKPX-G1205A-3700 (4V/30mA)
• 3-24V Piezo Electronic Buzzer Alarm 95dB
  — This article is referenced from the INAV official website: https://github.com/iNavFlight/inav/blob/master/docs/Buzzer.md