AR1000 Datasheet, PDF (32/37 Pages) Microchip Technology – Resistive Touch Screen Controller

8.5 5-Wire Sensor
A 5-Wire resistive touch sensor consists of a flex and stable layer, electrically separated by spacer dots. The
touch position is determined by first applying a voltage gradient across the stable layer in the X-axis direction and
using the stable layer to measure the axis touch position voltage. The second step is applying a voltage gradient
across the stable layer in the Y-axis direction and using the flex layer to measure the axis touch position voltage.
The voltage is not directly applied to the edges of the active layer, as it is for 4-wire and 8-wire sensors. The
voltage is applied to the corners of a 5-wire sensor.
To measure the X-axis, the left edge of the layer is driven with 0 Volts (ground), using connections to the upper
left and lower left sensor corners. The right edge is driven with +5Vdc, using connections to the upper right and
lower right sensor corners.
To measure the Y-axis, the top edge of the layer is driven with 0 Volts (ground), using connections to the upper
left and upper right sensor corners. The bottom edge is driven with +5Vdc, using connections to the lower left and
lower right sensor corners.
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.
Figure 16: 5-Wire Decoding
8.6 Summary
The AR1000 series resistive touch screen controllers will work with any manufacturers of analog resistive 4, 5,
and 8-wire touch screens. The communications and decoding are included, allowing the user the quickest
simplest method of interfacing analog resistive touch screens into their applications.
The AR1000 series was designed with an understanding of the materials and processes that make up resistive
touch screens. The AR1000 series touch controller is not only reliable, but can enhance the reliability and
longevity of the resistive touch screen.
DS41393A-Page 28
© 2009 Microchip Technology, Inc.