Magnetic encoders could replace potentiometers

Renishaw has developed a low-cost, high-speed rotary encoder with a novel, non-contact design that eliminates the need for seals or bearings, while reaching speeds of more than 30,000 rpm. The wear-free, frictionless design uses Hall effect sensors in a custom chip to sense the rotation of a magnetic actuator attached to the shaft.

The resulting encoder costs upwards of £50 - not much more than a precision potentiometer. It provides resolutions from nine-bit (512 count) to 12-bit (4,096 count), with measurement accuracies of 0.4 degrees.

As well as absolute versions, with parallel or serial data outputs, the encoders are available with incremental (1,024 pulse/rev), analogue, and linear current or voltage outputs. The linear options can be used in applications such as panel controls where, traditionally, potentiometers have been used.

The encoders are said to be shock- and vibration-proof. They have no internal moving parts, no seals to leak, and no glass optics to break. They are available with sealing to IP68.