Probably a bad ICM42688P Gyro but... | Betaflight | Page 1

zealous torrent May 6, 2023, 5:45 PM

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What version of BF are you on?

glossy compass May 6, 2023, 5:45 PM

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4.4.0 and tried 4.3.1

zealous torrent May 6, 2023, 5:46 PM

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I've heard there are improvements on the latest version of BF for the ICM42688P's. I'm not sure if those changes have made their way into and release version yet though so you may need to try a dev build.

glossy compass May 6, 2023, 5:47 PM

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the only thing I could think of is the gyro hardware lpf setting but that shouldn't be necessary

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i'll try a nightly

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just haven't made it that far yet

zealous torrent May 6, 2023, 5:56 PM

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glossy compass the only thing I could think of is the gyro hardware lpf setting but that should...

I thought this was a bug specifically for the ICM42688P that newer builds aimed to fix.

glossy compass May 6, 2023, 5:57 PM

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I have quads with this gyro that fly fine on 4.3, it's prolly a bad gyro or pour board design

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@zealous torrent The latest nightly won't even pick up the gyro, nice

zealous torrent May 6, 2023, 6:00 PM

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glossy compass I have quads with this gyro that fly fine on 4.3, it's prolly a bad gyro or pour...

oh, damn. ok. womp.

glossy compass May 6, 2023, 6:05 PM

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zealous torrent oh, damn. ok. womp.

4.4.1 no dice just yaws on the setup tab like a freakin owls head, lol. I hate this gyro. Even though when the board is right they are really good. Just too sensitive!

light shell May 6, 2023, 6:51 PM

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the fix is in 4.4.1 and later and fixes a bug that caused the cut off of the gyro's internal filter to be set way to high.
The gyro not being detected in 4.5 is likely a cloud build issue

light shell May 6, 2023, 7:45 PM

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I do remember that the ICM-42688P can pick up a static offset if it is moved slightly when powered up. Not sure if this is a BF thing though or if its just that specific IMU.

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but that offset was small, and not back and forth.

frosty crag May 7, 2023, 6:55 AM

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Can you make a log?

glossy compass May 7, 2023, 1:44 PM

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frosty crag Can you make a log?

Yeah I will make one here in a little while

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4.4.1 doesn't fix the issue. I'll post a BB log.

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@light shell @frosty crag here is a GD link with a video of the behavior. It "seems" that it only starts doing this after a battery has been connected and it has taken flight for any time at all. After it sits for a bit un powered then plugged in via USB the model in BF is solid as a rock.

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https://drive.google.com/drive/folders/1t6MY-nsqoaIBRZxMgEt6LdciCT9TF3ks?usp=share_link

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Oh, it's causing RTH to fly off in the wrong direction and you can forget a locked in acc trim.

glossy compass May 7, 2023, 3:16 PM

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@frosty crag Here is a log from this mornings test flight.

📎 btfl_001.bbl

light shell May 7, 2023, 8:24 PM

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glossy compass https://drive.google.com/drive/folders/1t6MY-nsqoaIBRZxMgEt6LdciCT9TF3ks?usp=sha...

Just so I'm sure: was the quad sitting stationary for the entire duration of that video?

glossy compass May 7, 2023, 8:58 PM

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light shell Just so I'm sure: was the quad sitting stationary for the entire duration of tha...

Yes

light shell May 7, 2023, 10:03 PM

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😐

frosty crag May 7, 2023, 10:03 PM

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Definitely use 4.5 Zulu with this gyro. I don't know exactly when, but the filtering was optimised for this gyro relatively late during 4.4 development, perhaps 4.4.1, not sure.

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The log looks alright. There is a little too much high frequency noise, but not a massive problem.
D is relatively high and Dmax in particular very high, leading to lag.
There is some 100hz resonance most likely props/frame exaggerated by D.
D filter is higher than normal.
Gyro filter is higher than normal.

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The gyro does not appear faulty.
These gyros have much less internal filtering than the MPU6000, with less delay as a benefit, but do let more noise through at the high end.
Even so I wouldn't say it's outrageously bad.

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To get rid of the really high frequency noise you could make gyro lowpass 2 into a PT2, and put all filter sliders in the default position.

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The resonance at 100hz is difficult to remove, the best way is to run less D. You could lower the lower limit of the dynamic notches to 80hz so that one would focus on it, but they introduce delay and distortion.
I would use more feedforward, less P and less D on this build.

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I don't see any evidence that the yaw axis is bad. I do see RC link issues, worse on yaw, but the yaw PIDs are doing what you request reasonably well.
In this image you can see abrupt setpoint steps leading to abrupt feedforward blips.
However the gyro for yaw shows that it is following those steps quite well.
Most likely you haven't turned the ADC off in EdgeTx. You need to do that.

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Overall the gyro is perfectly fine, I think, just that the tune is a little hot and the filters a little too high for it.

light shell May 7, 2023, 10:17 PM

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frosty crag Definitely use 4.5 Zulu with this gyro. I don't know exactly when, but the filt...

The icm-42688 fix is in 4.4.1.
But that bug shouldn't cause the quad to yaw back and forth in configurator like it does in the video.
Since the battery being connected seems to make a difference I suspect some kind of weird interaction with the GPS, but I'm not sure about the details.
I didn't spot any magnetometer data in the log, so I assume that there isn't one on the quad. Otherwise that could explain some odd yaw behavior.

frosty crag May 7, 2023, 10:20 PM

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If your problem relates purely to issues in Angle mode, please flash 4.5Zulu and try that.
It's possible that there is a pure accelerometer issue affecting angle mode, that I don't know, and I don't really know how to test that.
The GPS rescue has pitch blips every second so it is likely an M10 and the GPS is not working properly.

glossy compass May 8, 2023, 2:34 AM

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frosty crag If your problem relates purely to issues in Angle mode, please flash 4.5Zulu and...

Thank you for the log break down. I'm not the best at reading these yet but I get by just fine for tuning. This is Dave C's factory tune for this quad. I haven't tuned it yet. ADC filter is certainly off, just went and checked, when you said that, it messed with my head for a sec. Running Edge TX 2.8 and ELRS 150Hz, v3.2.0. with the correct preset, made by you actually. Yeah this BNF quad is pretty much straight out of the box from Flywoo. I put thread locker on the motor and bottom frame screws. Created an EMI shield from copper foil tape around gps leads and grounded it. Then wrapped the EMI shield in cloth tape, for protection and all. I put the arm braces on, checked it for potential mechanical resonance issues, made sure the stack screws were just right then put it in the air for a few flights. My first and second GPS RTH test went fine but my 3rd flew off and I had to take control, come home and power cycle the drone. It did it again after a few more RTH tests. I brought it in and noticed the model doing the twist in the setup tab. Other than that it flies fine but I'm 100% sure the ACC is drifting pretty bad. Probably why it wants to fly the wrong direction upon initiating RTH sometimes and trimming the ACC to a consistent state is impossible. I did try 4.5.Zulu finally and it seemed better but not fixed. Thanks, I would like to know what might cause the abrupt setpoint steps though. Would a very loose receiver cause this? @light shell

frosty crag May 8, 2023, 2:59 AM

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Sounds like a very good build

glossy compass May 8, 2023, 3:03 AM

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I'm going to rip it apart and go over it with a fine tooth comb if flywoo doesn't decide this acc is bad.

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complete rebuild

frosty crag May 8, 2023, 3:03 AM

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The issue with random gps weirdness isn’t an error on your part. Under certain conditions the initialisation of the GPS hardware isn’t quite right and the whole flight it just behaves weirdly. This affects about 1% of my tests. Typically it shows the home icon but then puts home in a weird place some distance away. If I return and power cycle it, the problem goes away, but disarm/arm cycles wont fix it. This appears to be an issue with the gps initialisation code and people are working on that as we speak. That problem has been there for many years.

glossy compass May 8, 2023, 3:04 AM

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Ok i've seen this a few times in testing. I'm in the tester s group.

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wish I had more free time though

frosty crag May 8, 2023, 3:07 AM

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There is a second gps problem that we do have a workaround for, there everything is perfect from takeoff but if the quad is drifting hard and the climb is >4-6 seconds, then during the climb the quad loses orientation and heads off the wrong way. This is also a long-standing problem but I only really figured out exactly what it was just now. So there is a PR in 4.5 that handles this much better than before. You can flash it with 4.5 Zulu and you’ll find that if the IMU is confused, the quad will initially head off the wrong way (this is inevitable, we cannot stop it), but then it will turn for home more effectively. Read the PR for details.

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If these things happen occasionally, it doesn’t mean your accelerometer is faulty. They are ‘normal’ for 4.0/4.1.

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What I don’t understand is what you say is wrong with yaw? I don’t see anything in the log that seems wrong.
What exactly is the yaw problem you are experiencing? What flight mode? Is it reproducible? Did it happen in the log?

glossy compass May 8, 2023, 3:10 AM

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Did you watch the video in on the goggle drive. I've never seen this behavior in the configurator from a quad sitting still

frosty crag May 8, 2023, 3:10 AM

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What do you mean by ‘doing the twist’ in the setup tab?

glossy compass May 8, 2023, 3:11 AM

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https://drive.google.com/drive/folders/1t6MY-nsqoaIBRZxMgEt6LdciCT9TF3ks?usp=share_link

frosty crag May 8, 2023, 3:11 AM

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Ok I looked. Was the radio on?

glossy compass May 8, 2023, 3:11 AM

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@frosty crag watch the IMG_2351.mov

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no

frosty crag May 8, 2023, 3:12 AM

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What was the receiver tab doing?

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What mode was it?

glossy compass May 8, 2023, 3:13 AM

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The radio was off and the indicator is on angle in the modes tab

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I thought the yawing model and the issue were related

frosty crag May 8, 2023, 3:15 AM

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Ok so maybe repeat and watch the modes tab and the receiver tab. Check what mode it thinks it’s in.

glossy compass May 8, 2023, 3:15 AM

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with the radio off?

frosty crag May 8, 2023, 3:15 AM

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Yes

glossy compass May 8, 2023, 3:15 AM

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ok it's up now

frosty crag May 8, 2023, 3:15 AM

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I’m suspicious that the Rx is a bit weird

glossy compass May 8, 2023, 3:16 AM

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I can fix that

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I think this is down to the newness of the ICM42688P at this point and it's not a deal breaker. 4.5.zulu is definitely better

frosty crag May 8, 2023, 3:17 AM

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You’ll know if there is random signal in the Rx panel. If the Rx panel is silent, then there’s no setpoint change.

glossy compass May 8, 2023, 3:17 AM

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the receiver tab is silent

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nothing changes

frosty crag May 8, 2023, 3:17 AM

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I think the quad image on the start screen comes simply from accelerometer values.

glossy compass May 8, 2023, 3:18 AM

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it does

frosty crag May 8, 2023, 3:18 AM

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Go to sensors and set max zoom and look at gyro, then acc

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Set to max scale.

glossy compass May 8, 2023, 3:19 AM

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all is still and everything looks good with movement

frosty crag May 8, 2023, 3:19 AM

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If you tap the quad you’ll see movement on gyro and acc. Check that acc traces are stable.

glossy compass May 8, 2023, 3:19 AM

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they stop moving when the quad stops

frosty crag May 8, 2023, 3:19 AM

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Yeah leave it alone and watch.

glossy compass May 8, 2023, 3:20 AM

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so far nothing

frosty crag May 8, 2023, 3:20 AM

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If the acc traces, especially yaw, are steadfast on zero, then check the setup screen

glossy compass May 8, 2023, 3:21 AM

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I got rid of that funky proprietary ELRS on the receiver earlier and updated to 3.2.0 BTW

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good and stable running 4.5.Z

frosty crag May 8, 2023, 3:22 AM

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It could be that there are transients on the acc that are not showing up. Set it to the maximum fastest time scale, 10ms I think. That’s still only one sample every 40 samples so you may miss single sample transients.

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If the quad spins on yaw in the main screen and the acc and gyro traces are dead flat well that’s something very peculiar indeed

glossy compass May 8, 2023, 3:23 AM

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It's not yawing right now

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it may do it after i go out and fly it

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but

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i have 4.5.z on now I'll test it tomorrow and see if this weirdness is gone

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whatever it is it only rears its head after flight

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on 4.5.z i can get a consistent acc trim inside, i couldn't do that before

frosty crag May 8, 2023, 3:26 AM

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If you’re game, flash Pr 12738 the gps IMU fix one. Set your max return angle to 40 degrees see how it goes. Don’t attempt a rescue if the wind is around 50kph or higher if it’s critical, but otherwise by all means test in high wind to find how high a wind makes it fail.

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I wonder if it’s an electrical issue.

glossy compass May 8, 2023, 3:27 AM

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Could be

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These ICMs are very power specific

frosty crag May 8, 2023, 3:27 AM

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But then if you see it on usb only then probably not. Very strange indeed.

glossy compass May 8, 2023, 3:28 AM

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yes but it's nit picky and you said yourself sometimes gps rth acts up

frosty crag May 8, 2023, 3:28 AM

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Intermittent faults are a pain. Often the only certainty comes when a part is replaced and book it’s all good.

glossy compass May 8, 2023, 3:28 AM

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I'm thinking of ordering a replacement FC ith a BMI270 and calling it a day

frosty crag May 8, 2023, 3:28 AM

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Yeah but in that Pr the gps will be far more likely to be good in situations where it would have been bad.

glossy compass May 8, 2023, 3:29 AM

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I'll test that PR tomorrow

frosty crag May 8, 2023, 3:29 AM

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Thanks

glossy compass May 8, 2023, 3:29 AM

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Thank you

frosty crag May 8, 2023, 3:29 AM

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I think the mpu6000 is available again and it’s been the most reliable and durable for me

glossy compass May 8, 2023, 3:29 AM

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for sure, i like the BMI270 as well

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50% or more 42688P give me crap

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Well I'll let you know what shakes loose, have a good night.

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@frosty crag that PR doesn't detect the gyro, lul

frosty crag May 8, 2023, 4:06 AM

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?

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its based on master, should be no different from any other flash. Did you include the correct gyro when specifying the build config?

light shell May 8, 2023, 7:45 AM

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Just another sanity check: have you been doing full chip erases when flashing and tried with just the minimal settings (I suspect you have since you must have flashed the board at least half a dozen times by know, but never hurts to make sure)

glossy compass May 8, 2023, 12:12 PM

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frosty crag its based on master, should be no different from any other flash. Did you inclu...

I downloaded the assets folder from the PR like we used to do and extracted the f405.hex file. It won't give me options for cloud build when I load locally. I'm sure I'm going about it the wrong way though. Something else, I loaded the hex file from flywoo, 4.3.1. It didn't detect the gyro. After I loaded the CLI DUMP they provide for 4.3.1 it did. I don't know of a cli command to detect a gyro. Right now it has the latest development release of 4.5.Zulu from the latest nightly configurator. I'll test that this morning. How do I use assets directly from the PR you specified with the new cloud build system.

glossy compass May 8, 2023, 12:12 PM

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light shell Just another sanity check: have you been doing full chip erases when flashing an...

10-4

frosty crag May 8, 2023, 1:00 PM

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These days you build the code in the cloud. Use Configurator in expert mode. Choose the settings when you build.

glossy compass May 8, 2023, 1:39 PM

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frosty crag These days you build the code in the cloud. Use Configurator in expert mode. Cho...

Ok, that's what I've done for the testing with the latest development build of 4.5.Zulu in expert mode which TMK is correct. I'll test that this morning and see how it goes.

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Packs are charging now!

glossy compass May 8, 2023, 4:31 PM

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😵‍💫

glossy compass May 8, 2023, 5:59 PM

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@frosty crag I loaded the latest development release in expert mode for 4.5.Zulu. Configured the quad from scratch, all looks fine. The 4.5.Zulu test went terrible, RTH would have put me somewhere in the woods a hundred feet away had I let it. When I landed and disarmed then tried to re arm I got RPM FILTER from OSD warning with no ability to arm until power cycle and my VTX broadcast a black screen to my goggles 50% of the power cycles. Everything else seemed to work as usual. Cool huh? All is working very well with 4.4.1 now. I'm getting RTH landings within 3 feet of home point on 4.4.1 but this could be a good GPS day. All is working well on 4.4.1 for the time being.

glossy compass May 8, 2023, 6:27 PM

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Looks like 4.5 still needs some fine tuning.

frosty crag May 8, 2023, 9:49 PM

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4.5 is good. Lots of people flying it with no problem. Must have been something very strange about that flash I think. None the less, stick with what works.

glossy compass May 8, 2023, 9:59 PM

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@frosty crag I will, I think this board is poorly designed, I don't have trouble with any of my other 42 quads besides an odd ball or two. It is what it is, thanks!

frosty crag May 8, 2023, 10:04 PM

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Good luck! I too have had boards that I just gave up on.

glossy compass May 25, 2023, 12:01 AM

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@frosty crag Rebuilt that quad from the ground up and moved the receiver t the rear and all issues cleared up. I had a feeling the Fllywoo ELRS receiver was causing some sort of interference as it was injecting RF noise into my camera feed being right behind the camera, she built right now. No more BNF quirks.

frosty crag May 25, 2023, 12:02 AM

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Is it flying ok now? I hope so

glossy compass May 25, 2023, 12:02 AM

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@frosty crag Yes on 4.4.2-Zulu just fine and all the way back to 4.4.1

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Thanks again she just needed an overhaul

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You would think these manufactures would know better

frosty crag May 25, 2023, 12:17 AM

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That’s incredible, really.

It’s the second recent build related ‘gyro failure’ that we’ve had here recently.

So glad it’s flying well!

light shell May 25, 2023, 7:27 AM

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That's interesting. I'll have to add "blast a ICM42688 with wifi" on my want to do list

#Probably a bad ICM42688P Gyro but...