I also would like to ask for magnetometer hardware and appropriate software. I have lost a small metal key from a children toy in my backyard and cannot find it. It is possible but unlikely that a magpie has taken it. With grass and rains, multiple searches have given no result. The next step is metal finder. Is it possible to make a program for Nemo-Mer-Sailfish which would use magnetometer to alert user about a piece of metal in the immediate vicinity of the device? Best wishes.