I'd like some opinions on the viability of adding an external magnetometer for use with the APM 2.0 purple kit I'm installing on my 600EFL.
The problem I am trying to overcome is interference from the Neu 1917 in-runner I have in my heli. When in the mission planner I can calibrate the mag and get good readings near the motor, consistent and accurate to ~10 degrees, however when I spin up the motor (rotor head off of course) I can watch the mag loose it's accurate bearing no doubt due to the coils in the motor charging/discharging. Rather than relocate my APM, I would like to install an external mag on the tail of the heli. Then I would have to sort out how to ignore the internal mag and substitute the external mag's signal.
Is it viable?
Want to help me figure it out :-)
BTW the GPS does just fine this close to the motor...
Ah, thanks for the information.
I haven't gotten to that point yet. I have everything wired up and working correctly, but I just got the correct ESC for my 500 heli. I was trying to power it on 4s (normally 6s), but couldn't get enough head speed to do anything.
It appears that on the 2.5 they only cut the SDA line, should have occured to me that if you don't initialize the on-board 5883L that it wouldn't be sending any info on the I2C or tripping the DRDY either.... some time I feel like I'm lucky to tie my own shoes LOL.
I'm also sure that they are not using DRDY on the external mag either :-)
So, cut SDA and use the external I2C.... simple. If you were really handy I imagine you could even flow solder over your cut if you cleaned the trace and cut right at the via.
Thanks Jeff. I'll give it a try. I've raised the whole APM2 by an inch for now and it made a big difference.
Well I've spent this pay periods play allowance getting all the hardware to build a variable pitch hexacopter, but I'll likely get an additional external mag for my spare "test APM 2.0" and try cutting SDA1 on it for the hexa. Should be a few weeks before I see the parts though, and I've got a 250 build using the ArduIMU V3 that I've been neglecting too...
Too much time spent working and never enough time for play :-)
So you think we can disable the Mag on APM2 by cutting the same line? Any idea where exactly?
I have 2 APM2 boards that I would like to use, but cannot, because they need external mags.
Oh, and then the question is also: how to wire up the external mag?