Pixhawk 2.4.8 Barometer/Height drift

as it states in the Headline I’ve got some problems with the Baro of my Pixhawk.
While some normal flights I noticed that the Copter is unable to hold a specific altiutde. It’s has some fluctuation up and down.
So I’ve looked in some logs and Yes I think this Behaviour of the Baro isn’t Normal:

For Comparison some Flight Log from the same Copter but with an APM 2.5.2:

So what could be the cause? I’ve read somewhere that Vibrations or/and the Wind flow inside the Case is an Issue, but look what happens as I Spin the Motors without Propellers lifting it 1-2m in the air. It’s better but still bad:

I’m running Arducopter 3.5.2 on a 2.4.8 Pixhawk. At the time were the logs origined there was literally no Wind.

I had the same problem. found that the piece of foam shrunk covering my Barometer .
opened my pixhawk and replaced it.

Beside good quality foam and wind insulation, a clean dc power supply to the FC is an advantage.
Cost is low and advantage numerous.
LDO dc voltage regulator for small required power such as FC, Rx, GPS/Compass do marvel :slight_smile:


Added an LDO regulator for the same reason. I have an 10 millivolt ripple which is excellent.

10 millivolt ripple is not too bad.
It is certainly better than the 3dr switcher module which is in the hundred of millivolts at 1A :disappointed:

I do have an output voltage noise of 4.17 μV RMS (10 Hz, 100 kHz) using TI LDO.
In short 2398 times less than yours :slight_smile:

Ripple rejection: 82 dB (100 Hz) ≥ 55 dB (10 Hz, 10 MHz)

The LDO, I am using, has not a lot of output current, Just 1A @ 5Volts, but for the PixXXX receiver and GPS/Compass it is enough.


Share an data flash log if you dont mind. What is the part number for your ldo?

Here is the LDOs I am using:

Of course you can find the full PDF from TI site. :slight_smile:

By the way removing noise from the source is good, having virtually none by using a separate small 2S battery for the electronics and opto isolated ESC is even better. (No common ground between sensitive electronics and very noisy switching ESC).


Thank you for sharing your experience. Wil definitely try this part.

Stil curious to see what your data flash log looks like on your ldo setup.

I used MC33269 , but the one you are using blows mine out of the water.