Arduino-Compatible Hall Effect Magnetic Switch (2 pack)
These devices include an on-chip hall (holzer) voltage generator for magnetic sensing, an amplifier that amplifies the hall voltage, a Schmitt trigger to provide switching hysteresis for noise rejection, and an open-collector output. These are sold as a pack of two.
Voltage: 5 VDC
Connection: 3 pins, +(middle pin), ground and S (data out)