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TOUCH-SENSITIVE SWITCH/SENSOR TECHNOLOGY |
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 ITW ActiveTouch, a unit of Illinois Tool Works Inc., has announced ActiveTouch brand touch-sensitive switch technology. The technology is available in "modular" switches, keypads and keyboards, or it can be integrated into custom bezels or panels. The input devices are said to be insensitive to liquid spills and other contaminants but have a familiar tactile look and feel.
The basic principle of operation is that a material capable of
supporting shear and torsional mechanical waves at ultrasonic
frequencies can have those waves trapped or localized by creating
specific features or geometries in the material. These trapped energy
regions, or "resonant cavities" are set into motion with transducers
and act as high quality resonators.
Resonance in the cavity area is initiated by an electrical impulse to
the transducer, then the vibration decays or "rings down" like a bell
that has been struck. A finger or gloved hand touching the front
surface of the resonant cavity dampens the vibration and reduces the
region's ring-down time. The reduction in ring-down time (decay rate)
is detected with a microcontroller which is multiplexed for multiple
switch positions. Since the sensor is actively "pinging" the sensor
area every few milliseconds, the sensor has the inherent capability of
self-diagnostics and self-adaptation in real-time.
itwactivetouch.com
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