Help GPS issue

Andre Meyer

Member
I have a multiwii pro setup on my 450 quad and I am experiencing a issue.
My multiwii pro board is the combo from hobbyking and I love it but I have recently grown bolder and connected my GPS module to try out position hold and RTH. I have a switch setup for horizon mode that works fantastic and I only activate ACC on horizon mode. In this mode the quad is stable and very agile. When I connect the GPS module to the board and wait for my GPS fix I can fly for about a minute when trouble starts. The quad starts to bank in a direction and I have to constantly apply stick correction to stop it from going in a direction. It also seems that my stick input feels a bit sluggish. I disconnected the GPS module and it flew perfectly again. Connected the GPS and same issue. I have not activated RTH or position hold at any of theses steps. Also in the gui program the GPS seems to work fine. Any Thoughts?
 

Motopreserve

Drone Enthusiast
Have you programmed in the magnetic declination in the sketch? You'll need to have that correct. If not, that could be causing issues.

Also, sounds goofy, but I remember having a hard time finding the correct way to orient the GPS on the MR. Turned out i was supposed to be ignoring the writingon top, instead aligning it based on a small dot. Annoying.
 

Andre Meyer

Member
I am sure I got the magnetic declination correct and I will have to check the aligning as you mentioned. Do you think this could cause an issue even without activating position hold or RTH. It seems to give me this issue even autolevel.
 

Motopreserve

Drone Enthusiast
No, I was talking about only when GPS was being used. If it's causing issues without GPS being utilized, that's a weirder problem.

Do you have a link to your specific board and GPS?
 


Andre Meyer

Member
I aggree very weird. Cant seem to find anything out there. I did engage RTH on the quad and it did return to a point then banked and I disengaged it knowing whats happening.
 

Motopreserve

Drone Enthusiast
I'm assuming that if you were running without GPS, then it must have the compass onboard? I know that the "newer" designs had the compass available on the GPS itself - because of interference when on the main board.

So you never had the GPS physically on the MR at all until recently? Or it was mounted but you just were not engaging it?

Those hobby king boards used to be know to have issues. Not sure if that's changed in the 18 months since I've messed with multiwii.

You might try downloading the standard Pro sketch from ReadytoFlyQuads.com and compare and contrast. See if anything stands out in the sketch as odd.
 

Andre Meyer

Member
You are correct in saying that I never had it physically on the board until recently. So it is definitely GPS related. Before mounting the gps the auto level function works perfectly. Once connected it goes weird then I remove it and all is well again. I will give the sketch a go and see if I spot anything.
 

Motopreserve

Drone Enthusiast
Very weird. Can't imagine the slight physical weight of the GPS is effecting it.

Checking the sketch is your best bet. Otherwise, the GPS may be defective.
 



Andre Meyer

Member
Yes looks exactly like the one on RTHquads. Must be components. I have a ublox Neo 6 GPS on OSD maybe I should give that a try and see what I get.
 

Motopreserve

Drone Enthusiast
Yep. They all look the same or similar. It's just that Witespy chooses the components for his boards a little more carefully.

His sketch is pretty good as well, so if yours is similar - that's always a good starting point.

Try the other GPS. Can't hurt :)
 

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