User guide

22 Document No. 001-64846 Rev. *I Getting Started with CapSense
®
2.5.2.3 Radial Sliders
Radial sliders are similar to linear sliders in that finger position is estimated using data from adjacent sensors;
however, radial sliders are continuous (does not have a beginning or end).
Figure 2-17. Radial Slider
Area contacted by finger
2.5.3 Touchscreens and Trackpads (Two-Dimensional Sensors)
Cypress‘s TrueTouch touchscreen solutions use mutual capacitance sensing. For more information on these
products, see TrueTouch Touchscreen Controllers. Cypress also offers trackpad solutions. Contact your local
Cypress sales office directly for more information. To find your local sales office, click here.
2.5.4 Proximity (Three-dimensional Sensors)
Proximity sensors detect the presence of a hand or other conductive object before it makes contact with the touch
surface. Imagine a hand stretched out to operate a car audio system in the dark. The proximity sensor causes the
buttons of the audio system to glow through backlight LEDs when the user's hand is near. One implementation of a
proximity sensor consists of a long trace on the perimeter of the user interface, as shown in Figure 2-18.
Figure 2-18. Proximity Sensor
Proximity Sensor
Another way to implement a proximity sensor is by ganging sensors together. This is accomplished by combining
multiple sensor pads into one large sensor using firmware (see Firmware Component) to connect the sensors from
the internal analog multiplexer bus. Make sure you do not exceed the C
P
limit for the sensing method when ganging
sensors together.