The BU52040HFV-TR, manufactured by ROHM, is a board mount hall effect/magnetic sensor with a detection latch sensing built electronically. It has a voltage range of 1.65-3.3V and can detect both bipolar and unipolar magnetic fields. This sensor is used to sense when two magnetic fields move past each other in order to detect the direction and speed of movement. It is ideal for applications in robotics, security and access control systems, and motors or motor systems.