HELP! Omnibus F3 no magnetometer :( DONE IT!;)

[Shawn]

I have tried 2 Omnibus F3's(V.1 and v.2) and 2 Ublox M8N GPS's with compass and using all the different combinations I can not get the MAG working.

Been using INAV but even flashed back to Betaflight and nothing.
If I leave it to discover the MAG on its own it just displays "NONE" if I tell it it's an 883 it just turns the MAG at the top red and a fail comes up on the right hand side. I have tried to set it by CLI and still the same.
I can't believe that I have been so unlucky as to get either two boards with the same fault or two GPS's pucks with the same fault.
What am I doing wrong?and if I'm getting it wrong everyone else must be.............
I have wired it exactly the same as in the "Blue Falcon" video.
https://www.youtube.com/watch?v=F5E_KGdpAzc
I have done it with and without a 3S battery wired up as well.
Absolutely flummoxed.

[Shawn]

Been reading about the "pull-up resistors" but noticed in the comments that someone set the "bus" speed to 200hz to get it to work but whats that?
If it involves fiddling with resistors I will dump the lot and get something that works as it should.

[ched]

I am sure you have had a good google round to find possible solutions but this thread https://www.rcgroups.com/forums/showthread.php?2964321-GPS-for-flying-wing-INAV suggests that, depending on what you are doing, you may not need a compass!!!

There is also this statement which you probably found:
"The trick was simply to remove the pull-up resistors from the external compass, and everything started working just fine…. I2C only needs one set of pull up resistors….

You can find out if your external compass has pull-up resistors by measuring with a multimeter between the +5V pin and the SDA or SCL lines (with everything DISCONNECTED)… if it shows open loop (high resistance) it has no pull-ups…. If you measure 10 kOhm (or some other value), those are the pull-up resistors…. You need to find a way to remove them from the external compass (probably using a soldering iron)."

So it would suggest that if you have a multimeter you can see if your gps puck has the pull up resistors.
I believe the 'pull up' resistors will be between the data output of the compass and the 5v line, i.e. pulling the output data up to 5v when no data is coming out (this is very much an over simplification).

[Shawn]

I need a compass on a camera quad.I have had a couple of fly-away's and they are not fun.
Just two incompatible items? Its should not be this hard. I think It will be easier if I just get an F4 board.I have put a couple of days into this problem and I am way past the fun part.

[Cheredanine]

GPS just isn’t my thing, sorry, but flyaways the answer isn’t a compas, for most it is setting failsafe

[hoverfly]

I had the same problem with Inav,  I spent hours getting nowhere. It is possible to fly wings with R.T.H. without a compass, quads require one, Not much help i'm afraid ,but in the end i bought a Micro Vector, Hobbyking  europe sell the f/c for  £30 less than rc.log. but you will need to buy the gps from them.

https://hobbyking.com/en_us/eagle-tree-systems-micro-vector-flight-controller-w-osd.html

https://www.rc-log.co.uk/vector-gps-module-v2-with-harness-cable.html

To go back to the flyaway problem they are usually caused by not getting a good sat lock before taking off.
Inav is still evolving and i'm not sure all the lumps have been removed yet..

[Shawn]

Thanks,they are expensive 
The fly-away's were due to no sat lock. I get set up and take off before they have lock. Got it down to a fine art,I have to stop and wait now for them to show

[atomiclama]

It's all relative.

If they are good enough to not do a flyaway and save your expensive camera ship, then they are worth while.

[Shawn]

Done it!
On the video for pull-resistors there is a comment below that says to drop the BUS speed from 400hz to 200hz. Which of course meant nothing to me.
Anyway I put "dump" into CLI to see if I could see anything about i2c and saw it.
set i2c_speed 400hz
so I copied and pasted that into the bottom and changed the 4 to a 2 and saved it.
Still no good but when I went back to see if it had changed just below I noticed.
set cpu_underclock = OFF
So again copied and pasted that into the bottom and changed it to "ON"
AND BINGO!!!!!!!!!!
Only taken me 4 days

[ched]

Well done mate. Thanks for posting the answer you found as I am sure others will have same issues in future.

Just make sure you have a good lock before takeoff.

[hoverfly]

Hmmm thinks, maybe time to look at Inav again..

[Shawn]

It's all relative.

If they are good enough to not do a flyaway and save your expensive camera ship, then they are worth while.

It has cost me £85 so far not counting the controller.
Already have a 4k camera so only a gimbal to fork out for now. I bought the cheapest everything and about 20% never turned up or was junk. But I get my money back and I am not in a rush was going to do this next winter but it is far easier than I thought and a lot of fun. ::)

[ched]

This is the 3 axis gimbal I have, it's about £60 but it has the Storm32 controller which is quite good as you can adjust everything on it!
I did have a Tarot 2 axis one but I couldn't get my SJ4000 to work on it as it was a different weight and cg to a gopro. The one I linked to works with the sj4000 no problems at all.
It can also have a bluetooth module added to allow adjustments via an app and a mobile phone which is very handy to tweek the setup in the field.

Go for a 3 axis as otherwise you can't get smooth panning shots.