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IMU Calibration Error

Gstudio

Member
Joined
Mar 14, 2021
Messages
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Age
51
Location
Italy
Mavic Mini 1
IMU Calibration Problem

After noticing the gimbal connection ribbon was cut, I purchased a replacement. When it arrived Friday evening, I set to work, disassembled everything, and, without any particular problems, removed the old, damaged one and connected the new one.

I dusted off the inside with a special brush (the kind used for smartphones, very soft and light), but there wasn't much to remove. I also applied a little thermal paste to replace what had been removed during disassembly. I also added a drop of glue (B-7000, the kind used for smartphones) to secure the connectors (I avoided using hot glue like the one that came with the drone).

I turned on the drone and noticed that the gimbal had started working again (I just turned on the drone and immediately noticed that the camera was stabilized again), so for me it was fine.

The next day, I decided to take a flight to check if everything was OK. I connected the RC, smartphone, and drone, and it gave me an error about the IMU needing calibration. I proceeded with the app as instructed, but the progress was sooooo slow; nothing flashed, and the step remained at 1/5, only to fail around 17-20%. It didn't ask me to reposition the drone. I tried several times, even following the suggestions I'd found about starting the calibration with the drone in a different position, but nothing changed.

Today, with a little more time, I reassembled everything to check the connections. Perhaps some connectors were inserted incorrectly or some debris ended up on the contacts. I didn't notice anything. I even used a small microscope to magnify the various areas of interest, but I didn't notice anything. Obviously, I double-checked the connector that connects to the MB, the one that connects to the gimbal, and the one that connects to the IMU. The connection ribbon appears to be perfect, no damage is visible. The problem remains.

I retried the calibration, connected the drone to the PC, and updated the firmware with DJI Assistant 2. I'm out of ideas now.

I found the cable cut overnight, and I noticed it during a flight where I didn't receive any other errors. Thinking back, I remembered that a couple of weeks earlier, the case the drone was in (its case, with the gimbal protector) had fallen from my shelf at home. I don't think the damage was consistent with that fall, but I haven't had any other occasions that would justify it. Maybe applying a filter to the lens gave it the final blow. But the IMU problem, after the fall, hadn't occurred to me yet during the last flight. Now I don't know if the problem is software: it seems unlikely, but never say never, and in any case, I don't know how to fix it.

1) The problem could be in the cable, perhaps it's defective. It was sold to me as compatible with both Mini 1 and Mini 2, but are they the same?

2) The problem is the IMU, which is broken. In this case, is it "enough" to replace the part? I read somewhere, but I don't know if it refers to all DJI drones or just certain models, that some parts need to be "enabled" by a special software they have in support. Do you know anything about this? Can I just buy a new IMU and install it or will it not work because it needs to be associated with the software that has support?

I realize that, absurdly, the IMU error can't even rule out an anomaly in the MB, but it all seems very strange to me.

Do you have any suggestions?
 
he problem is the IMU, which is broken. In this case, is it "enough" to replace the part? I read somewhere, but I don't know if it refers to all DJI drones or just certain models, that some parts need to be "enabled" by a special software they have in support.
Your model was made before this was implemented and if your IMU is bad you can simply replace it without serialization.
Make sure your Battery is above 50 percent or the calibration will most likely fail. (the drone knows lol)
If you are trying to do this calibration inside DON'T move outside away from metal and concrete.
If these don't help you may need an IMU.
Just make sure all your firmware is up to date, if not update and re-try your calibration.
 
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Sorry, but maybe I didn't understand a couple of things:

Can I calibrate indoors? In your answer, do you mean I should calibrate outdoors, away from metal and concrete? It's just my problem interpreting the translation of the sentence...

In previous attempts, the battery was 90% charged.

The drone is already updated to the latest available version, 0600. Would it be helpful to force a downgrade to a previous version? Someone told me about a service firmware, but I believe it's only available to support.
 
YES calibrate outdoors if possible! Make sure the drone and everything is up to date with firmware if this wont work you will need to replace the IMU.
 
YES calibrate outdoors if possible! Make sure the drone and everything is up to date with firmware if this wont work you will need to replace the IMU.
I had tried the calibration outdoors too, the satellites are detected without problems, but the IMU calibration does not work. It could be a problem with the accelerometers.
 
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Thinking back to previous flights.....did the drone "drift" in flight? Was its hover "steady"? if you experienced drifting or the drone hovered like it just came from the bar lol then you have a dead IMU and need to replace it.
 
Thinking back to previous flights.....did the drone "drift" in flight? Was its hover "steady"? if you experienced drifting or the drone hovered like it just came from the bar lol then you have a dead IMU and need to replace it.
During the last flight the only problem was the camera no longer moving, everything else worked. I was in a place between two nearby buildings, and I didn't have a good GPS signal, but I managed to arm the motors and raise the drone until it locked onto the satellites, so it was perfectly stable and still in the position where I stopped it (no drift or uncontrolled movement). This is why I can't figure out how the IMU could have been damaged.

I tried a reset or initialization procedure, but everything I tried was useless: DJI Assistant 2 (I also tried the Customer version, as reported in some posts) doesn't show any other firmware besides version 0600, which is the one already installed. I refreshed it twice, but it didn't help.

When I start the IMU calibration, it doesn't seem to even start. I'm tempted to reconnect the old flat cable, the broken one, to see if the IMU error still occurs (to check a new cable failure). I don't know if there is another way to perform an hard reset to factory default.

A curiosity: when the drone is on and I hold down the power button, it enters a mode that I'm not sure what it does. You hear a sound and the battery LEDs light up in sequence. It looks like a download mode, but I'm not sure if it could be useful for uploading something via ADB or specific software. But it's just a curiosity, I don't have any files to try uploading, and I don't even know what commands to give (assuming it's a download mode).
 
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I'm tempted to reconnect the old flat cable, the broken one, to see if the IMU error still occurs (to check a new cable failure).
Thats a good idea If the drone wasnt flying funny before I would think you have a cable or connection problem of some kind.
when the drone is on and I hold down the power button, it enters a mode that I'm not sure what it does.
I think thats the "mode" that pairs the controller to the drone.
 

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