DS41393A-Page 28

© 2009 Microchip Technology, Inc.

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.