Start / altitude failure

[thymjan]

After a crash with a tree my tello seems to have problems in getting the right altitude measurement. After starting the drone it doesn‘t hover in the air like before. It goes down immediately while the altimeter rises up several meters (up to 3 or 4 meters). It touches ground without stopping the motors and sometimes the altimeter gets negative values then (like -7 meters). I can use the controls like before, the video transmission is working fine. But the drone acts like it has to carry a heavy stone.

At some “fresh” starts it works like before then suddenly switches to the “heavy stone mode”. Or if I switch to sports mode I can lift the drone slowly then suddenly it goes up like a rocket and immediately falls down like a stone.

Maybe a temperature problem? Or a loose connection of the barometer?
Does anybody did experience such problems before?

 

[xcrost]

Try new props. Also you may have motor going bad.

 

[thymjan]

I’ve attached new propellers. This can’t be the reason.

How do you detect a motor goes defective? If a motor needs more current than before due to short circuit and this let the controller goes to hot. This might be a reason.
But how can one detect this at the tello?

And why isn’t the altitude then correct anymore? Because of the maximal current drain to the motors?

 

[volate!lo]

try to clean the bottom VPS camera (pinhole between the 2 big IR eyes)

 

[Ansia]

Do an IMU and Gravity calibration. Most likely the barometer will correct itself after IMU, the going up and down will fix after gravity.

 

[thymjan]

I did IMU calibration several times with no success. But can this be the solution when the drone at first attempt behaves normal and after 2 minutes goes to the heavy stone mode?

Can you explain how you do the gravity calibration?

 

[thymjan]

try to clean the bottom VPS camera (pinhole between the 2 big IR eyes)

I have a clear view to the tiny lens.