Datasheet

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER
DS41393B-page 8 Preliminary  2009-2012 Microchip Technology Inc.
2.3 4-Wire Sensor
A 4-wire resistive touch sensor consists of a stable and
flex layer, electrically separated by spacer dots. The
layers are assembled perpendicular to each other. The
touch position is determined by first applying a voltage
gradient across the flex layer and using the stable layer
to measure the flex layer’s touch position voltage. The
second step is applying a voltage gradient across the
stable layer and using the flex layer to measure the
stable layer’s touch position voltage.
The measured voltage at any position across a driven
axis is predictable. A touch moving in the direction of
the driven axis will yield a linearly changing voltage. A
touch moving perpendicular to the driven axis will yield
a relatively unchanging voltage (See Figure 2-1).
FIGURE 2-1: 4-WIRE DECODING