RC India

I finally tuned my quad with the apm2.6 board with version 3.1.2
But when I fly in loiter mode my quad tends to do the toilet bowl dance. This I because the magnetic north changes because of the magnetic interference caused by all the electronics onboard.
The solution to this is to do compassmot stated in the 3dr website. What this does is tells the compass the correct north by not registering the magnetic interference.

But I don't know that whether should I power my APM board with battery and USB at the same time or not. The Jp1 jumper is plugged in the board.
I need some assistance regarding this.
Should I remove the jumper and then power with USB and battery or what? :headscratch:

Yes,you can power APM from output rails while using it with USB.
But its highly suggested to keep them separate by removing JP1 and powering APM via power module or with a switching BEC via input rail. You can still use USB with it.

If you are using APM 2.6 ,I assume you are using an external magnetometer(because genuine APM 2.6 doesnt have an onboard compass). And if thats the case toilet bowl effect can also be due to wrong compass orientation(depends on the gps/compass module you are using). And you always have the option to place the external compass a lil bit farther from everything to avoid interference.

Similarly if using APM2.5 with onboard compass, compassmot can only compensate for interference till a certain extent (30% give or take), anything above that calls for placement of APM away from interference or using an external compass.

I am using a external GPS and compass and this is how I have placed it, far from all the electronics.

Okay, thats far enough in my opinion, so interference doesnt seem to be the sole reason for toilet bowl effect in your case. You have either not calibrated compass properly or compass/gps module orientation is wrong.

Even the GPS module has a front & back as shown in the image attached below if it has an onboard compass. So you need to check with your seller or figure it out yourself. You may need to remove the cover to compare it with other modules, thats what I did after getting it from Chinese vendors.

And yes you can power it with esc and do compassmot. First recalibrate the compass and see if it works, then perform compassmot. I think you already know the details for calibration and compassmot.

Wow! There's so many people with quads in Nagpur!

@Adityaamg:

I was thinking about building a quad too. It would be amazing if I could see your quad in action before I start my build. Where do you usually fly?

sir, my compass orientation is correct and the calibration didnt help much. i think compassmot might do the job. if the orientation was wrong the quad would turn around or something of that sort.

no problem sir, i will contact you as soon as my quad is fixed.

now one more problem has come up.
after the compassmot my interference was 5%, but now my motors are not spinning fast enough to take off even on highest throttle.

Is it possible to upload couple of more closeup picture please.

Adityaamg, check your THR_MAX and THR_MIN Values in the Parameters List. They should be between 100 to 1000.