Electronic Products - November 2003
Optical linear faders replace resistive devices
Contact-free devices provide lifetime accuracy
Useful in any linear control application from music mixing boards to machine control, Infinium® linear contact-free faders are presented as the first optical devices of their type. Unlike conventional linear potentiometers, the devices have an unlimited lifetime with no signal degradation, and require no A/D conversion.
The devices operate by reflecting IR light onto phototransistors via parabolic reflectors and an optical shutter. In addition, a magnetic resistance system provides a variable feel without affecting the operation, and may be adjusted from the top of the device.
The device's mechanism is separate from its electronics, so that the engineer can tailor the device to the components and circuitry of the design. The output can be configured to provide incremental or absolute position data.
The devices are currently available in three travel lengths: 45, 60, and 100 mm. Touch-sensitive and motorized versions will eventually be available. (From under $10—available now.)