# Land Detector not working after several landings

Source: https://forum.modalai.com/topic/471/land-detector-not-working-after-several-landings
Category: Flight Core and Legacy VOXL (https://forum.modalai.com/category/9/flight-core-and-legacy-voxl)
Tags: voxl-flight
Posted: 2021-09-30 22:44:18 UTC by m4v3r
Replies: 4 · Views: 1279

## m4v3r · 2021-09-30 22:44:18 UTC

Hey there^^
I'm having this issue where land-detection works smoothly for like 20 minutes after plugging in and then starts not detecting landings properly anymore.
Only thing that comes to mind is the Barometer not liking the thermal environment around the VOXL-Flight...

Any experiences regarding an active fan and barometer-covering foam?

I tried adjusting all related parameters up and down but it always only appears after several "service hours".

Once I flip a switch to acro and back (in this case to "manual") it will actually disarm by itself and immediately on flipping the switch, QGC's messaging will say landing detected. (coming from Mission mode)

## Reply by Chad Sweet (ModalAI staff) · 2021-10-02 00:22:36 UTC

Yes, we always install a barometer cap over the barometer in our assemblies and find that it helps significantly

The barometer can be affected by both wind and sunlight

The PX4 user guide is probably the best reference https://docs.px4.io/master/en/advanced_config/land_detector.html

## Reply by modaltb (ModalAI staff) · 2021-10-02 00:43:24 UTC

Hey @m4v3r ,

Might not be related, but when we moved from PX4 1.10 to 1.11, we had some issues with landing detection, and tweaked these: https://gitlab.com/voxl-public/flight-core-px4/px4-parameters/-/blob/master/platforms/v1.11/m500_4s_config.params#L153

## Reply by m4v3r · 2021-10-07 07:16:45 UTC (in reply to modaltb)

@modaltb Hi there, those look promising, thank you. I'll try and see if I can get them into testing today. cheers

## Reply by m4v3r · 2021-10-07 21:47:13 UTC

Hey,
I played around with them today a bit and found yes, your values did reduce the frequency with which the failure occurred so I'll continue tweaking there, thanks a lot.
Actually your link was double-helpful since I was looking for those specific parameters that regard the takeoff for quite some time now as well (without success...) ;D

I understand this is actually more closely related to PX4 but I very much appreciate the help anyway. ;)
I sincerely don't even remember anymore why yesterday I thought this must somehow boil down to the fact that it's running on the VOXL-Flight hehe.