Buy magnetic displacement sensors Magnetostrictive and magnetic displacement sensors do work for measurements in some applications, but they often control machine movement or serve other uses.

I recommend:  ASM carries a large line of magnetic-based positioning sensors, including non-contact. GMW Associates carries many kinds of magnetic displacement sensor devices that come unmounted to any type of armature or housing. Their stock includes non-contact, linear and angular components, as well as magnetic field measurement devices.

Buy linear displacement transducers Displacement transducers come in various forms, but they commonly consist of a tube-like body with a sliding armature inside. These will help control machine movements.

I recommend:  RDP Group carries transducer-type miniature displacement sensors that are stainless steel, durable and highly accurate. Omega has a large selection of displacement transducers, including long-stroke, miniature and some economical models. Now, if you need a sub-miniature or micro displacement sensor, head to MicroStrain. They have sensors so small, their pictures include pennies for scale.

Buy a laser or optical displacement sensor Both optical and laser displacement sensors serve measurement jobs well, and often quite practically.

I recommend:  Micro-Epsilon carries a triangulating laser, as well as optical displacement sensors. They also carry many other types of measuring and positioning devices, including the charge coupled device (CCD) sensor, which is discussed in other guides. Laser-View Technologies, Inc. is another option for a laser displacement sensor. They have several series of devices to choose from.