Quadcopter Building: How I'm Troubleshooting my i2c Compass Problem

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Happy flying!

[Painless]

UPDATE: Thank you to ALL of you that offered constructive support ideas. What a fab community we are - that wasn't the idea of the video but I've had some great suggestions and support. After getting to the point where it has to be the FC hardware or something in iNav (despite there being no other reports of i2c problems on this flight controller), I've flashed it with Betaflight 3.5.2 and guess what - the compass worked straight away! So, not hardware at all but either iNav or something to do with iNav and this version of the FC.. Stay tuned!

[pspicer]

My first car - 1970s Austin Allegro - engine the size of a breadbox (seriously), electrical problems, build quality problems, unattractive as all get out. Man how I *LOVED* that thing. Could work on it all day ... but could work on it - not like today's cars... those were the days my friend .... Oh (comes out of reminiscing) - love this series and look forward to following in your footsteps.

[MCsCreations]

Yeah, Lee... I agree with you. There's not much to try other than swapping the FC... 😕
I hope you can solve it soon!

[chattonlad]

Had the same problem with a similar setup Lee, got around it by using an M8N compass module for a NAZA lite. Just tick the box for GPS compass.

[Blindman-kc]

Tnx Lee!
I'm stuck with the same problem, but with Ombnibus F4 v3. FC does not recognize GPS, but when I flash it with Betaflight works! Tested with F4 v3 and F3 v2 Pro. It looks like the problem is with iNav 2.0.0. Now I know that I do not need this new spare GPS, just what I ordered. ;)

[amitsekhon]

Hi Lee, Once i had I2C problem with OLED screen that wouldn't work.After struggling for days, i found that the problem was 5V.I was feeding 5V instead of 3.3v.So your I2C signal line's pull up resistors should be connected to 3.3v.

[vchan]

Check whether the UART for I2C is already occupied by something else.... spare that for magnetometer and the compass will work

[dempa]

As always great content! Especially for someone who is just getting in to this hobby. Quite curious if the gps and compass modules work on another fc (maybe connect them to a fc where you have gps and compass working with iNav?) or maybe with a different fc-firmware combo. But I guess that is something for the next video! :)

[mr_sheen_airsoft]

Some compass modules have pullup resistors fitted on so if your FC board has them aswell then you can have issues with i2c,
I've had this issue with a compass and a pixhawk FC, I have found and removed the resistors from the compass module and it works.

[StigBSivertsen]

Nice video Lee 😊 very strange that you we're not able to get it work... as you mentioned I am able to get it to work and it works fine...

[FRACTALNERDZ]

i have a xrotor f4 flight controller dont have a i2c port kann i resource it somehow??

[roberteicke]

What size Pull Up Resistors did you add? (I'll give that idea a try) I am having difficulties getting Baro & Compass for Mamba F405 Mk2 working on INAV. FYI Thank You Lee for your contributions to this hobby!

[mikeboon]

Hi,
I have searched high and low for the same issue, and believe me, I have done exactly the same steps even down to the position where we soldered the pull up resistor. I've done all of that even before stumbling on your video! Just FYI I'm using the same BN-880 GPS/Compass and if you look at the unit PCB, there are already 2 1k pull-up resistor on the GPS unit. Technically it should already work out of the box on a I2C.
Unfortunately I'm using a Airbot F7 (not the Omnibus F7 or the NXT), which is not supported on iNav (there is no barometer, even if I install an external Baro, there is no such Target in iNav). As for Betaflight the Target is there, but I can't try the older firmwares before 4.0 as the Targets were not there. I somehow believed that the issue lies with the Betaflight FW.

[Rcbeacon]

I haven't used INAv so these are just guesses based on some I2C experience. Is there another firmware you can load (even if not INav) just to check the I2C port and connection to the compass ? The scope should have shown something. Is INav using the correct CPU pins for the I2C port on the fc board ?

I haven't had any I2C problems recently but the last time was on a large DSLR gimbal. The sensor wire run was over 500mm. Solution was I2C buffers at each end. Not likely a problem on your quad.

[atschris]

I had something similar with a different project and used an Arduino with a really simple sketch to verify whether the i2c interface was working -and it wasn’t in my case. It’s just another tool in our box.

[fpvjules]

Hey man, my FC has no SDA/SCL pad, is there any way to remap it or any way to solve it?

[salukikev]

I'm here trying to learn about I2c- this is because unlike FC's with assorted UARTs, it seems like most controllers have only one I2c, and crucially that is the preferred (only) interface for GPS, Compass and Barometer. I'm lacking a barometer but using a BN880 compass/gps. Now I have to find a way to integrate an external baro. Any ideas? (Flywoo F411 Hex FC).

[lptrung]

The video is awesome, you can post the video connect hc-sr04 ultrasonic sensor to INAV 2.0, because I want my quad hold is low height, thank you

[AhmetOmerOzgen]

Do you calibrate compass while esc's are turned on?

[narok]

I will change the mapping for the I2C pins to other free UART. Whit "resource i2c_scl 2 b10"
and "resource i2c_sda 2 b11" for example I am using an I2C magnetometer in an old Matek F405 under betaflight