The wheel speed sensor measures the speed and direction of rotation of the road wheel. These sensors provide data with several different automobile systems, including the anti-blocker brake system and electronic stability control system. Wheel rotation sensors, as a rule, include gear (or optically encoded) shaft and magnetic (or optical) sensor. The sensor has a speed at which teeth or signs pass by. Speed sensors can control the crankshaft or rotation of the drive shaft in vehicles that do not need to know the speed with which individual wheels are rotated. Otherwise, they control the rotation of the axis of the drive of each wheel. There are two types of magnetic sensors: variables and based on the Hall effect. Both types detect the teeth of the steel gear when rotating under the sensor. Variable sensors detect a change in the inductance of the coil of the wire, when a steel tooth passes in the immediate vicinity. Hall effect sensors measure the change in the resistance of the semiconductor slab due to the force of the applied magnetic field.