"The offsets are not a measurement proportional to the distances of the sensor from the centre of the frame but are a measure of the magnetic field and its orientation wrt to the frame. Two different sensors held in the same position within a uniform…"

"Hi Arshish, The offsets and the compassmot values are not directly related. The offsets are related to how the sensor element is positioned relative to the copter body and the compassmot values relate to how the magnetic field at the sensor is…"

"http://copter.ardupilot.com/wiki/common-compass-calibration-in-miss...
Note:
In Copter-3.2.1 and later offsets are considered acceptable provided their combined “length” is less than 600 (i.e. sqrt(offset_x^2+offset_y^2+offset_Z^2) < 600). Prior to…"

"Hi Flavio,

It seems that you have checked most of the likely issues that you should when attempting to diagnose the symptom you are facing. Your props are mounted in the correct orientation and are spinning the correct way and your ESC's are all…"

"Check out http://dev.ardupilot.com/wiki/building-ardupilot-with-arduino-windows/
Here you will find instructions on how to download and compile the code.
The current and earlier version of the code is available on…"

"Check out the JD-IOBoard. You can use both the hardware/software or just run the software on your own Arduino board: It connects to the APM via a telemetry port and looks at the mavlink data to allow you to perform actions based on the state of the…"

"Hi Clifford,
Your DC-DC converter looks a bit hefty but should do the trick for powering the APM from your lipo. Unfortunately in its default state, the APM will not provide the correct signalling to the motor driver circuit for your needs. It would…"

"Hi Edwin,
If you have successfully compiled the code then you will have an ArduXXXX.px4 file in your build directory. To upload this to your Pixhawk you can select 'load custom firmware' in Misson Planner and select this file. Loading previous…"

"Hi Edwin,
So you have managed to compile the code and upload it to the Pixhawk? If you send me the code you are using to measure weight with the Arduino it will help - I will private message you my email address. You can use the Telem2 or the Serial…"

"Hi Edwin,
Sounds like an interesting project! I have used pixhawk/APM in a similar way a number of times. Sending data from an external Arduino via a serial port and having it logged along with the other Ardupilot data is fairly straight forward. I…"

"Hi John,
I have used both the APM and Pixhawk for processing/logging data from external sensors. I am just getting into another project doing the same. I have only just looked at the latest version of the code and it seems that there are a few…"

"I use a Pixhawk to collect data from a kite which can spend considerable periods in various orientations. I use the Ublox M8 with a dual band omnidirectional antenna. This seems to work well. "

"Hi, 
I have used hall effect sensors for anglular position sensors previously. Something like this for less than a dollar or so should do the trick: http://goo.gl/HQElZe. The output of this sensor should be readable directly on one of the APM analog…"

"Hi Marvin,
(I´m using putty connected to the usb port of pixhawk at 38400 baud to display the console; I prited out "numc" and "data" from the UserCode.pde)
The USB port is used for telemetry/mavlink data so if you connect directly to it using Putty…"

"If you can program a picaxe then you can program an arduino. You can make your APM do what ever you please (within the capabilities of the hardware) - including arming, changing modes, setting a given pin high at a given altitude and much more...…"