The TAT200 reaction torque sensor based on a metal-foil-strain gage can check residual torque on fasteners or monitor in-line running torque on servo and stepping motors. In one example, according to developer Futek Advanced Sensors Inc., Irvine, Calif., (futek.com) the TAT200 determines the torque needed to overcome a fastener's friction and tighten it. The one-piece device is maintenance free, has no rotating parts, and needs no power supply.

Another version with a built-in amplifier or digital output, works with a stepping or servo motor and a PLC or computer in robotic applications. A few key features for this line, according to Futek, include accuracy, durability, several mounting options, and capacities from 5 in.-oz. to 500,000 in.-lbs.