Omnibus F4 V3 Pro Diode Removal

Hardware Planes
1

Hello. I have been following the guide here on setting up Arduplane on an Omnibus F4 V3 Pro:

https://ardupilot.org/copter/docs/common-omnibusf4pro.html

In particular removing the diode so that I can isolate the servo power rail and power servos from the BEC on my ESC. However I am not sure it is working as expected. If I simply plug the battery in the servos spark into life and I can control them even tho the diode is not there and no external bec on the servo rail. Also plugging the powered bec into pwm1 powers the board. Surely if I have isolated by removing the diode this should not happen?

Video here: https://youtu.be/RdaOwGIE-O4

If I have the this wrong then what diode have I removed?! :joy:

Thanks

2

Hi Carl,
You are the proud owner of a (bad) clone of the Omnibus F4 V3 Pro.
Cheers Sascha

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3

She is flying great though and with the diode weight reduction :joy:

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4

Hi carl,
Good to know you can laugh about that. :+1:
The flight controller may be working fine. Different from your intention you should be aware the servo voltage rail and the voltage regulator of the microcontroller are still connected to each other. A voltage surge or noise on the servo rail can disturb the sensors or the STM32.

Keep it flying.

5

I’m running the v5 to the servos from a stand-alone BEC. Just the signal wires going into the FC now. As I just didn’t trust it. Its a bit messy cable wise but should be safer for the FC.

6

Do we see that very often, e.g. with SG90s? Because I chose an ESB without a BEC and don’t want the weight of a dedicated BEC. So I have to run them off the integrated one…

7

Hi Hajo,

I would not use the Omnibus voltage regulator to feed the servos. It’s not up to the job. The small blue servos gained popularity for being cheap. They are known to pull (relative) huge currents at initial movements.
To save weight on a BEC is the wrong way expecting a reliable working plane.

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