Motion sensors act by picking up movement from nearby objects and returning it to the detector, this detects and gives a very accurate measure of movement and time and convert it into a readable signal for digital devices.
Rotary encoders also known as shaft encoders are electromechanical sensors that monitor the position of the shaft or axle, and then send it back digitally. There are 2 types, absolute encoders which provide speed and position information and incremental encoders that output a continuous stream of pulses. Rotary encoders are commonly used in many automation applications that require precise shaft unlimited rotation such as the robotics industry, electronic industry and machine production.
Linear transducers are used to measure movement in a straight line. They convert displacement into an electrical signal, that's proportional to the amount of displacement. These sensors are commonly used in very harsh, cold climates , and under high vibration and shock levels such as power turbines, satellites, hydraulics and any other application where accuracy is critical.
Magnetic pickups are sensors which detect the speed of a moving part. This motion is picked up by the magnetic field, which induces a measurable AC voltage. These sensors are often used as components of speedometers or tachometers, which are integral parts of engines and industrial equipment.
A linear variable differential transformer (LVDT), is used to accurately measure linear displacement. There are many types of these motion controllers and they have different armatures, temperature range, built in electronics and stroke lengths and have been specifically designed to measure multiple targets. It can be used in a range of applications within industry or research as it can easily be modified to fulfil different sensing tasks.