A44E Hall Sensor Module

The sensor on this module is an A3144-family Hall-effect switch (marked "A44E"), which switches its output when the south pole of a magnet comes close to its marked face. It is a unipolar, non-latching switch, so the output returns to idle once the magnet moves away, and most boards include an LED that lights on detection. The A3144 is rated for 4.5–24 V, so power the module from 5 V and connect its digital output to any GPIO pin or interrupt input. It is used for wheel and fan RPM measurement, door and lid sensors, magnetic limit switches and simple position detection.