ARDUINO M391 Hall Magnetic Standard Linear Module AVR PIC Electronic Components Electronic Hobby Kit

This sensor is used to detect magnetic fields. The current, and thus the voltage, running through the sensor is changed in relation to the presence of a magnetic field. This sensor is designed so it can tell you the amount the voltage has changed as an analog output, and if the voltage has changed as a digital output. Since the sensor can provide digital and analog outputs, there is a surprising amount you can do with it. You can easily make a working sensor, or make a much more complicated one.