Replies to This Discussion

Permalink Reply by Peter Seddon on June 10, 2011 at 11:50am

I have just asked a similar question because I don't think you can use the APM with a 5843 due to the different supply voltages and probable voltage swings on the I2C lines that will exceed the 5843 voltages .... but I wait to see what the experts have to say.

Peter

ps I have been doing some further research and this answers the question about using the Sparkfun 5843 http://code.google.com/p/arducopter/wiki/Quad_Magnetos
pps calibration is I believe not necessary on the APM as the software does it whilst flying.

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Permalink Reply by Brett Horton on June 10, 2011 at 12:21pm

Thanks, 

Again keep in mind we are using this on a fixed wing aircraft,

We where test flying, including the mag yesterday. Compass disabled, everything good in auto, compass enabled, switch to auto mode the aircraft flys figure eights, but not around a point, gets blown down wind.... 

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Permalink Reply by Brett Horton on June 20, 2011 at 5:13am

Hello again guys,
Still no joy concerning the Mag.
It seems to hold ok in the lab but once air-born, the A/V just circles aimlessly.
Any suggestions?

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Permalink Reply by Brett Horton on June 20, 2011 at 7:12am

Has anyone had any luck with the compass on a fixed wing aircraft?

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3D RoboticsPermalink Reply by Chris Anderson on June 20, 2011 at 7:25am

Yes, we use the standard DIYDrones mag all the time with fixed wing--it works great. The mag is soldered to the board and enabled via the CLI as shown in the manual:
http://code.google.com/p/ardupilot-mega/wiki/Magnetometer

Are you using the standard DIY Drones mag?

Have you soldered it to the board as shown? If not, did you tell the software what orientation you have it in?

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Permalink Reply by Brett Horton on June 20, 2011 at 12:15pm

using the mag from DIY, I have enabled it in the CLI, Using the mag with the extended cable (GPS) about 12 cm in lenght, the board has the correct "solder blob" as well

 

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3D RoboticsPermalink Reply by Chris Anderson on June 20, 2011 at 12:22pm

John, I still can't help you until you answer both questions. The orientation of the board changes everything. Pins forward or back? Components up or down?

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Permalink Reply by Brett Horton on June 20, 2011 at 12:24pm

Sorry, pins forward, components down, just as the software states....

Also I go by "Brett" ;)

 

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3D RoboticsPermalink Reply by Chris Anderson on June 20, 2011 at 12:39pm

Good. Now a few more questions:

Have you tried a mission with the mag disabled? (Mags are only need in fixed wing aircraft autotakeoff. They're mostly used for multicopters).

Can you post a screen shot of your mission plan?

How did you set your declination?

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Permalink Reply by Brett Horton on June 20, 2011 at 1:01pm

The main problem seems to be in the South through north quadrants.... North through south seems fairly consistent in rotation in ninty degree increments

 

Permalink Reply by Brett Horton on June 21, 2011 at 4:26am

Yes many times, with good results...

Have not set the declination as I have not seen a good explanation of how to do it correctly.

Permalink Reply by Brett Horton on June 21, 2011 at 4:47am

Our issue seems to be deviation not declination? On the east side of the compass, the swing to a specific heading lags, on the west side of the compass, it overshoots badly, pointing the nose of the A/V from north to west, the compass swings almost 180 degrees

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