Interlink Electronics VersaPad USB - Manual (Page 4)

USB VersaPad®
Integration Guide
www.interlinkelectronics.com
2
3.0 Theory of Operation
The touchpad sensor is a four-wire resistive type. The pad is composed of two resistive layers
separated by an air gap. One plate is used for the X-axis and the other is used for the Y-axis.
When pressure is applied, the two resistive plates make contact. A microcontroller measures
position and pressure then uses advanced, proprietary algorithms to yield smooth mouse
functionality. Figure 1 shows the electrical representation of the sensor and Figure 2 shows a
simplified exploded view of the sensor.
Figure 1: VersaPad Equivalent Electrical Circuit