Connect Servo to Pixhawk 2.4.8

Hi am making my first drone using Pixhawk 2.4.8, and I want to add a servo motor.I saw on the documentation that I have to power the servo rail with a 5v battery to do that and also to use a Zener diode to prevent any spikes that can harm the Pixhawk. Should I connect the components like in the scheme below?

-Servo model: Feetech FS90R
-Bec model: bec

I have never used a zener diode in any of my bec connections. but all other connections you have there are 100% correct. as long as your bec provides a stable reliable voltage I don’t see a need for a zener diode. just get a good quality bec.

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Thanks for your reply ! Do you know how to choose a good bec ? I bought this one bec link do you recommend something else ?sorry for these questions but i am a complete begginer in all this.

Or don’t connect it to the servo rail and power the servo directly.

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It all depends on many things but the one you have link I have one that looked identical to yours on a old pixhawk build never had any issues. If you are going to be hanging expensive equipment off of this keep in mine skimping on cost early on from unknown manufactures can lead to some very bad results. a lot of this depends on your over all goal and obviously budget. Mauch power supplies are some of the best out there and are reliable but some time shipping costs can be prohibitive depending on where you live looks like from your like is Greece? you could also as @dkemxr says create a separate rail that just powers the servos of you copter. That does add a level of difficulty. What will the servo be doing?

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something like this you mean ?

Yes I am from Greece and its a little difficult to find variety of products here, but I will look if there is any bec of this brand! I am buidling for my thesis an agricultural drone which will be able to fill with water its tank and I am trying to make a linear servo actuator which will lower the tube of a pump in order to suck water to fill the tank.

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Yes. Can’t go wrong with that.

ok I will try it I hope it works! thanks for the help

can i ask you something else should i also connect the ground of the servo rail to the ground of the bec or is it ok in the scheme above?

I would say yes… but @dkemxr can tell you better… you need to warrant that you have a common ground somewhere, not exactly at the connection shown in the image

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Often times you will need to keep a common ground you can try to hook it up like the photo you posted but if you see that it is not functioning it is more than likely you need to keep common ground between the two. it may also work considering you will probably share a common ground among the battery or another connection.


Hi Dear
Can you help me in how to connect servo motor in 9,10 channels in pixhawk2.4.8 flight controller.

Power the servos from a BEC and connect the servo signal leads to Aux 1 & 2.

Can you tell me how to set up the aux pin output in mission planner.

Go here

Hi Dave,
All signals need the same reference, therefor the GND of the BEC must be somewhere connected to the GND of the pixhawk.
I think, this should be added to your advice for better understanding