# Quadrotor offboard servo control

**URL:** <https://discuss.px4.io/t/quadrotor-offboard-servo-control/6753>\
**Category:** Uncategorized\
**Created:** [May 29, 2018, 2:43pm UTC](https://discuss.px4.io/t/quadrotor-offboard-servo-control/6753 "2018-05-29T14:43:38Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mjulius66](https://discuss.px4.io/letter_avatar_proxy/v4/letter/m/34f0e0/32.png) [@mjulius66](https://discuss.px4.io/u/mjulius66)\
**Post date:** [May 29, 2018, 2:43pm UTC](https://discuss.px4.io/t/quadrotor-offboard-servo-control/6753/1 "2018-05-29T14:43:38Z")

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Hello

I am studying a quadrotor’s response to a payload drop using a servo. I am using an ODroid (running Ubuntu 16.04) to run a control algorithm and generate a reference trajectory for the drone to follow. I know I can operate the servo by setting one of the aux1 passthroughs to a switch on my RC in QGroundControl. I am using the 3DR DIY Quad airframe.

I want to send a command from the ODroid to the Pixhawk to flip the servo at a specific time. This way the payload is dropped at the same time in every experiment. Should I try to send a mavlink message containing the command to operate the servo? Edit the mixer file and send a control input to flaps/spoiler/brake? Any help or insight into how servos work on PX4 would be appreciated.

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**Author:** ![ernsten](https://discuss.px4.io/letter_avatar_proxy/v4/letter/e/3ab097/32.png) [@ernsten](https://discuss.px4.io/u/ernsten)\
**Post date:** [August 4, 2021, 3:19pm UTC](https://discuss.px4.io/t/quadrotor-offboard-servo-control/6753/2 "2021-08-04T15:19:24Z")

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Hey,  
have you got it working? I am interested in how you controlled the servo in offboard.