Operation
QSlide works with a simple linear resistive element that can consist of discrete resistors connected in series, a resistive thick-film layer, or an optically-clear indium tin oxide (ITO) film for use over liquid crystal displays (LCDs). Dedicated algorithms are used to determine the touch position independent of signal strength, thus making detection both accurate and reliable.
QWheel the electrode consists of a simple resistive ring element that can be placed behind any dielectric panel. Three capacitive QTouch channels are connected to this ring, QSlide and QWheel based products process signals to 7-bits of absolute position. Output is via a standard SPI or I2C serial interface. No external active components are needed.
QSlide and QWheel can sense through panels up to
3mm thick, even through gloved hands. When placed
behind glass or plastic, the circuit creates a smooth,
sealed, indestructible rotary touch control that can
replace virtually any mechanical encoder or potentiometer.
It does not require a hole or knob and therefore has no
service or maintenance problems.
Copyright © 2010 REID Industrial Graphic Product Pty Ltd. All Rights Reserved.
QSlide and QWheel are reliable, cost-saving alternatives to existing capacitive sensing technologies and can also be used wherever a mechanical control would otherwise be employed. They use spread-spectrum modulation for good EMC performance and low RF emissions. It features drift compensation to account for slow changes due to aging or changing environmental conditions and automatic recalibration for life.
QSlide and QWheel Technology
QSlide and QWheel based products are touch sensors that eliminate the need for conventional resistive sliders or rotary controls. Based on the same charge-transfer technology used for touch buttons in QTouch, they can be thought of as 'capacitive potentiometers', where the wiper is a human finger.