July 2008
Intermediate to advanced
544 pages
16h 52m
English
Content preview from Computers as Components, 2nd Edition
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4.4 Component Interfacing 175
Voltage across the screen
Contact
Conductive sheets
Spacer ball
Push
V
x
V
xpos
x position
1
ADC
FIGURE 4.23
Cross section of a resistive touchscreen.
4.3.6 Touchscreens
A touchscreen is an input device overlaid on an output device. The touchscreen
registers the position of a touch to its surface. By overlaying this on a display, the
user can react to information shown on the display.
The two most common types of touchscreens are resistive and capacitive.
A resistive touchscreen uses a two-dimensional voltmeter to sense position. As
shown in Figure 4.23, the touchscreen consists of two conductive sheets separated
by spacer balls. The ...