I was looking at my flight log for my last flight, where I crashed into a tree, and I noticed that one of the IMUs flatlined right at the point where the Iris+ started to go crazy.

It happened like this. I was doing an automated lawnmower pattern to survey a local park. It was about 95F, with about 5 mph wind, gusting occasionally to 10 mph I'd guess. The run took about 10 minutes, so then it was going to return to the first waypoint and then Return to Launch. But I decided to switch it off auto from the controller, and just bring it in with RTL, because I was afraid the battery might be getting low since I've been having problems at the ends of "long" flights.

At that point it started dipping and yawing, pitching and rolling. I nearly had control of it when it went into the tree. Looking at the logs I see that all output from IMU1 flatlines right at the point where it starts going haywire.

So what do I do now? I've repaired the broken arm, and can repair my camera, but what should I do about the IMU? How can I test it without having it go haywire on me? Do I need to replace anything?

Epilogue: To top it all off - the survey run was perfect, but I had my camera settings wrong, so everything was overexposed!

136.BIN

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  • This reply was deleted.
    • flatline IMUs are failed IMUs

      I'm new to this, so I'm not sure what that means in terms of which part is which. Do I have to replace the Pixhawk?

    • Thanks for the info. I think it flatlined when I switched to RTL, but then I panicked and switched to Loiter, which is just as bad in that situation I guess. As soon as I switched to RTL, it started dipping and spinning.

      Since I bought it from someone off of Craig's List, it's not under warranty, but I'll send them the log file and see what happens.

  • Sitting at work so can't read the file but what firmware were you using and did you have AHRS_EKF_USE turned on?

    On 3.2.1 it's off by default but folks were advised to turn it on.

    -Mike

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