Quantum Research Group E115 User Manual

Overview
Using the
E115
How it
Works
Quantum Research Group Ltd.
Page 1
US: +1 (412) 391-7367
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The E115 board is designed for rapid
evaluation of the QT115H 'sync chip'
QTouch™ IC. The board includes four
keys with corresponding backlighting
LEDs to indicate touch on each key.
The keys are made using squares of
copper area around empty holes in a
PCB located under the plastic panel. A
piece of translucent material diffuses
the light from the LEDs to provide a
broader area of illumination.
Connections are provided for external
interfacing, and several E115's can be
connected together for extended
daisy-chaining of two or more E115
boards.
The board is powered by a single 9V
alkaline battery with a low-voltage
detect LED.
To use the board right away:
1. Insert a 9V alkaline battery into the clips on the board.
2. Place the E115 on a desk, or hold the board so your fingers do not come near
the keys or the circuitry on the sides of the main board (there are sensitive
components and traces there; If they do, keys may calibrate against your finger
or detect your finger, causing LEDs to come on).
3. Turn on the power slide switch. The ICs require less than a second to calibrate;
after this time you can touch the keys to make them light up, in any
combination.
The E115 has four QT115H chips, one for each key. A connector in the middle of
the main PCB conducts the sense traces to the top PCB 'key plane' to turn the four
squares into independent touch sensors.
The gains of the QT115H's are set high enough (by using appropriate values of Cs
caps) so that the sensing fields will penetrate through the plastic panel laterally into
the centers of the squares. The squares are not isolated from each other via ground
traces; since the QT115H's operate in time-sequence, they do not cross-interfere
with each other. Furthermore, each sense electrode is connected to ground while
waiting its turn to sense, so that the touch action does not bleed across into adjacent
keys.
This configuration lets the sense fields permeate the centers of each key but not
outwards from each key. Touching near the edge of one key will not cause an
adjacent key to detect.
A schematic of the E115 is found at the end of this guide.
www.qprox.com
UK: +44 (0)23 8045 3934
E115 USER GUIDE
techsupport@qprox.com
QTouch is a trademark of QRG Ltd. R1.0 7/01