It’s something [mircemk] demonstrates, with an Arduino-powered magnetic field strength meter that uses a UGN 3503U Hall effect device. The circuit is extremely simple, comprising the sensor ...

Well, let us take a quick look at one of them… According to the datasheet, SS49E is a linear hall-effect sensor ... Arduino Uno, you can use other similar boards like Arduino Nano, Pro Mini, etc. to ...

[John Crombie] had a crack at building one using linear Hall effect sensors and magnets as the ... [John] utilises the Arduino pro micro for its copious analog inputs and USB functionality.