A basic magnetic speed sensor, also known as a magnetic pickup or magnetic speed probe, is a type of sensor used to measure the rotational speed of a target object, such as a gear or a shaft. It operates on the principle of detecting changes in a magnetic field caused by the rotating target.
Here's how a basic magnetic speed sensor works:
Magnet and Sensor Housing: The sensor consists of a housing that contains a magnet and a coil of wire. The magnet is typically mounted on the rotating target, such as a gear tooth or a shaft, while the sensor housing remains stationary.
Magnetic Field Variation: As the rotating target moves past the sensor's magnet, the magnetic field around the magnet fluctuates. This change in the magnetic field induces a small voltage in the coil of wire inside the sensor housing due to Faraday's law of electromagnetic induction.
Voltage Output: The induced voltage in the coil is proportional to the rate of change of the magnetic field, which is directly related to the rotational speed of the target. The faster the target rotates, the more rapidly the magnetic field changes, leading to a higher induced voltage.
Signal Processing: The induced voltage is a very weak signal, so it needs to be amplified and conditioned for further processing. The sensor often includes electronics to amplify the signal and convert it into a more usable form, such as a digital signal or an analog voltage that corresponds to the rotational speed.
Output Signal: The processed output signal can be used for various purposes, such as displaying the speed on a dashboard, controlling a system's operation based on the speed, or transmitting the speed data to other parts of a larger system for further processing.
Applications: Magnetic speed sensors are commonly used in automotive applications to measure the speed of vehicle wheels or transmission components. They are also used in industrial machinery, robotics, and other applications where accurate speed measurement is essential for proper functioning.
It's important to note that the accuracy and reliability of the sensor can be influenced by factors such as the distance between the magnet and the sensor, the quality of the electronics used to process the signal, and the speed range over which the sensor is designed to operate.
Overall, a basic magnetic speed sensor offers a simple and reliable way to measure rotational speed by leveraging the changes in magnetic fields generated by a rotating target.