[kennyevo]

Hi!

I've built a diatone whitesheep quad with a Revo using ublox gps, I've balanced the quad, but it still goes backwards after takeoff. In the telemetry I see that the horizon is shaking up and down even if the quad sits still on the table.

I calibrated everything again and again with no luck.

Any ideas are welcome!

[Mateusz]

Any ideas are welcome!

Are you using external magnetometer on a mast far from power wires/esc ? Calibrated outdoors with help of oplink far from metalic objects, and it is always green in the place you fly ?

[kennyevo]

I've calibrated outdoors, everything was green.

I don't know if it uses the gps' magnetometer, I'll disble the gps tomorrow and we'll see if anything changes.

The gps is mounted on top of a gps mount, so it's quite far from everything.

[f5soh]

Are you using INS13 ?
How are the MAG alarms while flying ?

[kennyevo]

Are you using INS13 ?
How are the MAG alarms while flying ?

Yep I'm using ins13, don't know about mag alarms, my old laptop is wired, but will record the telemetry tomorrow

[kennyevo]

Hm, how can I replay a log file in the GCS?

[@marc]

Disconnect you FC, and select Logfile from the dropdown list.

[kennyevo]

Hm, it doesn't seem to work, maybe my log is corrupted :/

Here's my log: https://drive.google.com/file/d/0B_2MdV3di_UMcEFVYUpRMDUybGc/view?usp=sharing

is it possible that it was caused by the foam below the FC? It looks like it's a little tilted, but the calibration should eliminate this problem, right?

[kennyevo]

Okay, tried it wouthout the gps, without any calibration it's much better, it now goes forward after takeoff, but I think that's just because I did not recalibrate the things.
Is it possible that my gps causes all my problems? It's a UbloxNeo-6M, it was packed with the revo.

[f5soh]

Most of the time after arming, your Mag alarm is solid Red and that looks normal using a onboard mag on a small frame.

INS13 retrieve all sensor measurements and compute data for Attitude estimation.
https://librepilot.atlassian.net/wiki/display/LPDOC/INS13+-+GPS+Navigation

You can assume the attitude estimation can't be ok with a Red mag alarm or when GPS is indoor (position and velocity jumps due to bad rx).
A small jitter while the frame is steady looks normal.

Do you still use the OP15.05 release or you miss Oplink firmware update ?

[kennyevo]

Oops, I did not update my oplink

While using the gps, it looks like the quad is a little nose down and right, even if placed on the ground and leveled to be totally horizontal :S

[f5soh]

As a test for your Accel calibration (Attitude > Accelerometers calibration), you can go to UavoBrowser > RevoSettings and change the FusionAlgorithm to INS13Indoor

It uses a fake GPS data so you can use INS13 indoor and allow to check Accels.

You can try Comp+Mag+GPS that should show the same level like basic algorithm.

[kennyevo]

My gps doesn't have a mag, so I think it's using the Revo's mag, is it possible that the cables interfering with the magnetometer? (motor output)

One noob question: I need only one red and black wire coming back from the escs, that's powering the revo, right?

[Mateusz]

My gps doesn't have a mag, so I think it's using the Revo's mag, is it possible that the cables interfering with the magnetometer? (motor output)

One noob question: I need only one red and black wire coming back from the escs, that's powering the revo, right?

If you don't have external magnetometer then it is using one on Revo. It's build dependent but very likely this won't work to get stable INS31.
Please have a look here https://forum.librepilot.org/index.php?topic=995.msg7204#msg7204

[kennyevo]

So the best option would be to buy an external mag or a better gps with external mag?

Could you tell me what type should I buy that's compatible with the revo?
Thanks