APM 2.8 Jumper setting for MAG (external compass)

Forum users,

I have a quick question: the following information was found on the internet

  • 2.8 uses jumper cap to choose, find the MAG pins on board, pluging in jumper cap is built in compass, taking off jumper cap is external compass

I will be using the APM 2.8 and the external GPS compass that comes bundled in.

Question: Do I need to remove the MAG jumper when I plug-in the GPS module.

I am not confused does the compass comes built into the APM 2.8 or it is part of the external GPS unit?

Thank you in advance.


APM 2.8 (which I think is not an official APM product) has a build in compass. It comes enabled by default, and can be disabled by removing the jumper.

If your external GPS unit also happens to have a compass on it too, it’s up to you, which to use. The compass part will usually have a separate i2c connection which is different to the serial GPS connection.

I did that but I believe both compasses become active, since rotating the apm also changes the compass direction on mission planner, unless it uses the gyro/accelerometer data to assist with that!.

I searched for schematics and only found the one for APM2.5, also hobbyking (who claim indirectly in their youtube video of doing the 2.8 upgrade) don’t have such data or even a clear explanation of the jumper setting

I saw a video on youtube (in italian) and he moved the jumper to the upper position (https://www.youtube.com/watch?v=Usly04XunWw) [you can use youtube subtitle tranlsation, it was ok]

This is an aged thread, but maybe helpful for somebody else trying to figure this out. I have a 2.8 version clone board and I did not mess with the jumper. I just selected in mission planner in the compass calibration to use the external compass and leave the onboard compass as-is. It seems to work fine here with yaw errors being acceptable. Before I checked the checkbox that says to use the external compass I had more yaw error due to EMI from primary wiring to the motors (quadcopter). So I believe it is working OK by just selecting to use the external compass and leaving the on-board compass enabled.

Also, with the APM2.8 and a Neo 6M module, the external compass (four pin connector with blue and white wires) plugs into the port directly underneath the GPS port, and not into the I2C port. I think, based on my own experience with this board, that removing the jumper by the GPS port is optional unless you want to totally disable the internal compass. I also think (but not totally sure) that leaving the jumper on will revert to the internal compass in the event the external one in the 6M module fails. And the reason I think that is because I can unplug the external compass, and not make any changes in the calibration or settings in MP, and it seems to use the internal compass but with more yaw error.