I have a quadcopter on which I want to connect a servo, I bought a ppm to multiple PWM converter to connect on the flight controller PPM output, but I don't find how to tell betaflight to control the servo through the converter.

I tried to configure the servo in the servo tab but it does nothing.

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    $\begingroup$ Why are you using a PPM to PWM converter? The "ppm" on the board is an input (unless remapped with resource mapping) and betaflight/inav do not output PPM. You want to connect your servo to a "motor" output and look into the servo mappings to those motor outputs $\endgroup$ Aug 17, 2021 at 16:14
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    $\begingroup$ @BrydonGibson Ok, I understand better know, I think I can't do that with this FC even if there's several pins that are physically available there's no documentation. Thanks $\endgroup$
    – Entretoize
    Aug 18, 2021 at 6:12
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    $\begingroup$ Look into the "resource" CLI command in betaflight. You can use it to figure out mappings based on what the target developer has decided for this board. Effectively, it is the documentation $\endgroup$ Aug 18, 2021 at 14:14

1 Answer 1


Flight controllers usually have PPM inputs, not outputs. The PPM output is on your radio module.

You can indeed connect the PPM output signal to both the FC and your PPM->PWM converter: the FC would be controlling the motors, and the converter would be controlling the servo. There's nothing to configure in Betaflight in this case: the value from a certain channel will be applied directly to the servo.

A better idea is to configure Betaflight to control your servo: this avoids using the converter altogether, saving space, weight an money. If you have 1 or 2 servors to control, it's recommended to use feature SERVO_TILT, otherwise CHANNEL_FORWARDING is an option. Here's the Betaflight documentation page with examples. Note that you need to assign resources (pins with timers) to servos before you can use them.


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