Searching on google I found various projects to get a digital compass with Arduino.
The sensor that is used is the HMC5883L or similar and have a negligible cost.
The idea would be to implement in the Satnogs software this sensor that should be mounted on the rotor, obtaining at the turning on of the rotor the pointing to the North, without having to search for it manually (especially when we are outdoor in portable). It works with I2C bus
I can do some tests but I’m not very good at C ++ code.
Here some links on how to get the digital compass
Hey!! The auto homing by using compass it works only for the azimuth axis. If we use accelerometer + magnetometer (like this), we find homing for both axis. The sensor is mounted in the axis of elevation and start measure when the motors are off (due to interference), specifically when the rotator power up. Also this system needs an input from satnogs client (the position of station) in order to calculate correctly the true north. The problem is in elevation axis because the sensor isn’t mount to the antenna. I opened an issue for auto homing with accelerometer and magnetometer.
It’s been done already. Have a look at SARCNET.ORG I built their Arduino Leonardo based rotator with the magnetic sensor. It works very well via Gpredict and hamlib.
Bob