Touchable potentiometer

By Control Engineering Staff November 9, 2005

Quantum Research Group has released an enhanced version of its QWheel chip, the QT511. It features low power consumption, enhanced operation under difficult sensing conditions and the ability to place a mechanical button in the center of the scroll wheel without experiencing false detects on operation.

QWheel touch wheel technology is effectively a ‘capacitive potentiometer’, where the wiper is a finger. The electrode consists of a simple resistive ring element placed behind the plastic panel; three capacitive QT sensing channels are connected to this ring, and the signals processed to 7-bits of absolute position. The result is output on an SPI serial interface. The device can be set to sense through panels up to 3-mm thick, and even through gloves. The entire circuit with the electrode ring can be fabricated on a single-sided PCB. In many cases it claimed to be less expensive than mechanical equivalents and more reliable.

QT510 uses spread-spectrum modulation for high immunity to external noise sources and ultra-low RF emissions. It also features drift compensation to account for slow changes due to aging or environmental conditions. It will also operate in a low power microamp mode. Prox mode allows the device to detect hand movement up to 50 mm away from the panel surface; this can be made to activate a display or product from standby, before the user even touches the product.

For more information visit https://www.saelig.com/pr/qt511.htm or
https://www.qprox.com/products/qwheel_qt510.php

Contact info: Quantum Research Group
651 Holiday Drive Bldg. 5/300
Pittsburgh, PA 15220
Tel 412-391-7367
Fax 412-291-1015