technical question about imu & phantom 3

xrider · Oct 18, 2019

good evening pilots

as ive mentioned on the title i ve got 2 questions

1. how easy is it when it comes to swap imus?? mine is goin to die and i wanna ensure that no harm is goin to happen during swap.. is that easy as this guy shows in the video??

and

2. after how many hours or flightime is a phantom 3 goin to be ment as old??

silly question the 2nd one.. but im a bit curius after the rare imu error that happened

suddently it said gyro and acc error.. init failed.. and no calibration could be completed.. tapped the battery.. but this solution doesnt last for long.. so i have to replace the imu..

just curiosity about from what age problems begin.. ?

Kirby Johnson · Oct 18, 2019

xrider said:
good evening pilots

as ive mentioned on the title i ve got 2 questions

1. how easy is it when it comes to swap imus?? mine is goin to die and i wanna ensure that no harm is goin to happen during swap.. is that easy as this guy shows in the video??

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and

2. after how many hours or flightime is a phantom 3 goin to be ment as old??

silly question the 2nd one.. but im a bit curius after the rare imu error that happened

suddently it said gyro and acc error.. init failed.. and no calibration could be completed.. tapped the battery.. but this solution doesnt last for long.. so i have to replace the imu..

just curiosity about from what age problems begin.. ?

From an engineering standpoint, there is really nothing to wear out. Electronics per se, do not have mechanical parts which wear and in theory last a very long time. The exception, which incidentally does not really apply here, is circuits which consume large amounts of power and generate high temperatures. In that case circuit failure may occur from thermal fatigue. IE the mechanical stresses generated from repeated thermal expansion and contraction. I would think the circuits in a DJI drone would seriously outlast the motors. After a couple of rounds of motor replacements via bearing failure, you MIGHT be concerned. But you would in all practicality, not still own the drone.

FWIW, I have a Phantom 3 Advanced which I bought a little before I joined PPilots, here, say early 2016. It still satisfies my drone needs and has been quite trouble free, but I do not fix things which are not broken. As a young engineer I learned that lesson over and over again.

xrider · Oct 18, 2019

yeah.. i know.. if it works dont try to fix it..

ive got same drone as you.. its 2 years old and its got about 50 hours of flightime.. this odd thing with imu seems to be temperature related as when its cold and humid it throws imu errors everywhere.. but when its hot.. everything its back to normal.. that was the question about age and problems

i dont wanna play this game anymore.. i dont wanna fight midflight with errors and drifts.. i dont wanna crash it or worse lose it.. so.. i am goin to replace the imu module.. thats the question about if its easy to take the imu off as it seems in the attached video.. i need some positive energy here because i dont want to harm its fc underneath the imu box.. ?

quaddamage · Oct 19, 2019

Kirby Johnson said:
Electronics per se, do not have mechanical parts

The thread is about IMU. And IMU is actually a MEMS device - so it actually is mechanical.

I wouldn't repair something which isn't broken though.

xrider · Oct 19, 2019

quaddamage said:
The thread is about IMU. And IMU is actually a MEMS device - so it actually is mechanical.

I wouldn't repair something which isn't broken though.

i know that.. but i dont want to repair it.. im going to replace it.. and yes.its having serious issues when it comes to fly.. drone gives imu errors during startup procedure.. or sometimes ive got yaw errors midflight.. its time to replace it.. but i dont know if its simple as it seems in the video above..

has anyone replaced the mems chip on a p3?? please let me know if its simple.. i saw the 4 clips.. are they come off easily?? when it comes to put the new one in.. do i have to be carefull of the fc underneath?? im a bit anxious and worried because i dont want to harm it.. sorry for my silly behaviour.. ?..

KachemakDiver · Oct 19, 2019

It is very simple to do. And also more times than not, the imu doesn’t need to be replaced. Just remove the imu by gently unlocking the 4 clips, lift the imu out of the square, use care when unplugging the ribbon cable.( it has a adhesive on the connector that needs to be removed) After the imu is removed, tap the imu on all 4 sides by hitting it on a solid surface,, not real hard but with a little bit of force. Doing this will free up the inside component which sometimes gets stuck. Believe it or not,, but I have fixed several P3’s that had imu issues by doing this. AND I learned about it from researching on this forum! My opinion,,,give it a try ?

dronesky · Oct 19, 2019

KachemakDiver said:
It is very simple to do. And also more times than not, the imu doesn’t need to be replaced. Just remove the imu by gently unlocking the 4 clips, lift the imu out of the square, use care when unplugging the ribbon cable.( it has a adhesive on the connector that needs to be removed) After the imu is removed, tap the imu on all 4 sides by hitting it on a solid surface,, not real hard but with a little bit of force. Doing this will free up the inside component which sometimes gets stuck. Believe it or not,, but I have fixed several P3’s that had imu issues by doing this. AND I learned about it from researching on this forum! My opinion,,,give it a try ?

That method worked for me to onP3P

xrider · Oct 20, 2019

hello pilots

well.. i didnt hit the imu as this way was already done several times till it got stuck permanently for some unknown reason.. i could hardly perform any calibration to it.. and by the next start up.. error was there.. again.. this thing was happening about a year.. till drift and yaw errors occured mid flight.. so i went ahead and searched for another imu.. time was passing.. so ive started a thread here giving logs of what was goin on with my odd problem.. gave it more time.. because i was veeeery nervous of tryin to take the old imu out and put the new one in.. time was ticking harder and louder every single day more and more.. so.. ive said "now or never" .. and swaped them of.. calibrated.. and.. here we are.. i see its values on state.. its been sooo long time that i was watching it fly error free.. now i dont wanna let it get down.. im so happy that its so stable.. so are its sensors as it seem.. hehe

well.. i feel that i need to learn more about imus on drones and their function.. can anyone give a link to have a look.. i dont find very helpful the one on wiki..

thanks ?
xrider

KachemakDiver · Oct 20, 2019

Just click on the search icon and type what topic you want information on.
You will get A LOT of threads to read, and find answers to probably everything you want to know.

xrider · Oct 20, 2019

KachemakDiver said:
Just click on the search icon and type what topic you want information on.
You will get A LOT of threads to read, and find answers to probably everything you want to know.

most of what ive found are about imu calibration.. what is imu and imu errors whose solution was tappin them.. i am looking sth like troubleshooting or the cause which affect negatively an imu.. need to know how to take care of it correctly.. just in case of seein sth odd again (fingers crossed and prayin for everything is gonna be fine from now on).. ?

KachemakDiver · Oct 20, 2019

Simple answer is not to do hard landings, flipping over, or any crashes. Sudden impacts are the main cause of a “ sticking imu issue “. That is why smacking the imu on a hard surface takes care of the problem. Sometimes they stick hard so you need to smack it fairly hard. It does help to know the orientation of the imu compared to the impact it suffered. I have bought a couple that I had to smack hard enough that I thought would break it, and it solved the issue. Never heard of one that just stopped working for no reason. I believe the imu controls the accelerometer for the 4 motors, the gyroscope and compass calibrations.
Somebody correct me if I’m wrong!

xrider · Oct 20, 2019

yep.. impacts doesnt like them.. impacts like crashes or not so good care taken during transportation.. but.. how about the impacts that it takes to get unstuck if they get "stuck" or "fail" as mc likes to say with the error in red?? how about temp changes in there??
have you seen an imu of a p3 how sensitive looks?? its so tiny.. maybe it seem unbreakable but its not.. this blackbox is full of air.. and in the middle its another box.. so tiny as your small fingernail.. it seems to be more sensitive that we think they are..

KachemakDiver · Oct 20, 2019

You just remove the imu from the black box that is glued to the main motherboard. You do so by gently lifting the 4 little tabs that hold it in the black box. Trust me, you can smack that imu harder than you think. I thought the same thing as you the first time I did it. Be sure to smack it on the flat surface, not on the edges or corners. If the internal component is stuck hard, you gotta smack it hard. And be careful of the side that has the ribbon cable,,that you can damage easily.
I calibrate my imu in cool temperature that way it doesn’t take as long to warm up when I want to go fly.