Sensors Detect Touch Through Thick Materials

The 16-key QT60160 and 24-key QT60240 touch-sensor chips detect human touch through panels measuring up to 50 mm in thickness when teamed with a scanned X-Y passive matrix. Their ability to operate on 1.8 Vdc makes them suitable for use in mobile phones, MP3 players, and other hand-held devices. Key sizes, shapes and placement are almost entirely arbitrary, and each can be individually tuned via an I2C interface for sensitivity, response time, and other parameters. External circuitry consists of a few passive components. Both devices feature adaptive automatic calibration and drift compensation and an adjacent-key suppression function, which ensures that if more than one key is partly covered by a finger, only the intended key registers touch. Available in MLF-32 packages, prices for the QT60160 and QT60240 start from $0.95 and $1.20 each/100,000, respectively. QUANTUM RESEARCH GROUP, Pittsburgh, PA. (412) 391-7367.