# Rotation Sensor ![V5 Rotation Sensor](https://3510336827-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M7yGVyBrcpSR8SDSikj%2Fuploads%2FLthIMz3lnouATT9ygI5y%2Frotationsensor.png?alt=media\&token=ef6a55c9-4019-4648-b0be-3ae166a194eb) ### Functionality The **V5 Rotation Sensor** is an smart sensor to determine the angle bound by \[0,36000) and the position in centidegrees, as well as the angular velocity in centidegrees / second. The sensor connects to the [V5 Brain](https://wiki.purduesigbots.com/vex-electronics/vex-electronics/vex-v5-brain) through a smart port, and functions similarly to a[ encoder](https://wiki.purduesigbots.com/vex-electronics/vex-sensors/3-pin-adi-sensors/encoder) or [potentiometer](https://wiki.purduesigbots.com/vex-electronics/vex-sensors/3-pin-adi-sensors/potentiometer). ### How it Works The measurement component of the sensor is comprised of a Hall Effect sensor that measures the magnetic field of 2 magnets to track the absolute angle (\[0,36000)) of the rotation sensor. The angle resets every full rotation of the rotation sensor. A chip inside the rotation sensor (a Cortex M0+) then keeps track of the total rotations which acts as the relative position measurement, which does not reset every rotation. Since the rotation sensor angle ([get\_angle](https://pros.cs.purdue.edu/v5/pros-4/group__cpp-rotation.html#gac675e49bc52b4b25ce2351742b69b6cb)) is absolute, as it's based on the magnetic field generated, the angular position of the shaft will not reset when it loses power. However, since the chip loses power the position ([get\_position](https://pros.cs.purdue.edu/v5/pros-4/group__cpp-rotation.html#ga28a657dab4a1609b0bddc8ba0c345b57)), which is relative, of the rotation sensor is not tracked and it resets to zero every time the sensor is turned on. #### Teams/Individuals Contributed to this Article: * Alyssa Agarie (Former VEX Competitor) * [BLRS](https://purduesigbots.com/) (Purdue SIGBots)