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Do you notice the start-up beeps the motor/ESC makes when you plug in the LiPo battery? It beeps even when there is no buzzer (piezo beeper) connected, and we can turn that feature into a lost model alarm.

It can be useful when you don’t have a buzzer installed, or in case your buzzer fails in a crash. Check here for more useful tips on quadcopter building/flying.

Warning: running motor beeper for too long could result in overheat, even burns out your motors in some cases. It’s best to beep the motors once or twice then stop.

In this tutorial we will show you how to do this in ESC’s with BLHeli firmware. To set it up there are only 2 settings you need to configure in BLHeliSuite:

  • Beacon Strength – How loud you want the beeper to sound (default 80, range from 1 to 255); 120 is a good value IMO, I suggest trying different values and check if the motors and ESC would get too hot. I don’t recommend setting this too high to prevent motors and ESC overheat
  • Beacon Delay – After how long the beeper starts to activate being idle (default 10mins, IMO 5 or even 2 mins is a good idea for our purpose)

There is also Beep Strength. This setting might seem relevant but actually it’s not. It only controls the volume of the start-up beep, so just leave it as it is.

A bit out of topics, if you’ve ever wondered how ESC’s can make sound, they don’t. It’s actually the motors that makes the sound. The pitch and volume of the sound is controlled by signal from the ESC. It’s even possible to play a jingle with motors 🙂

In the latest Betaflight, you can now turn on the motor beeper using a switch! This frees you from using a regular piezo buzzer.

The option is available on the configuration tab, under DShot Beacon Configuration section.

Alternatively you can also set it in CLI:

set beeper_dshot_beacon_tone = 3

The setting can be set from 0 to 5.

Setting it to 0 will disable motor beeper. By default this setting has a value of 1 which means it’s turned on but at the quietest volume. Higher numbers make it louder, but if you make it too loud it’s possible to overheat your motors even damage them. I think 3 is a good value to start with, and make sure to check your motors for sign of overheat.

You have RX_SET and RX_LOST options – if you want to activate DShot Beacon with a switch on your radio, enable RX_SET. If you want motors to beep when radio signal is lost, enable RX_LOST.

However, I don’t recommend using RX_LOST. Motor beeper is not very loud, so of you are too far away that your radio can’t get a signal, you are probably also too far away to hear the beeper anyway. If your motors continues to beep for minutes even hours while you are searching for it, there is a big chance that you can fry the motors.

To be able to activate DShot beacon with a switch on your radio, simply assign a switch to the beeper mode in the modes tab. When you flip this switch, the motors and buzzer will beep at the same time.

flight modes - acro mode, horizon mode, angle mode

Edit History

  • Jun 2017 – article created
  • Apr 2019 – added warning about RX_LOST (I think you should disable it)

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