RE: CapSense Evaluation Kit - Walk through the userguide

Workshopshed — Mon, 30 Jun 2014 09:30:42 GMT

I found the details of the sensitivity settings on the data sheet

Sensitivity Control

This feature allows specification of the minimum change in sensor capacitance that can trigger a sensor state change (OFF to ON or vice-versa).

■ Sensitivity can be specified individually for each CapSense button and slider.

■ Sensitivity can be specified as one of the four available values: 0.1 pF, 0.2 pF, 0.3 pF, and 0.4 pF.

■ Higher sensitivity values can be used for thick overlays or small button diameters.

■ Lower sensitivity values should be used for large buttons or thin overlays to minimize power consumption.

The programming guide explains the sensitivity is a little more detail in that the setting is measured in counts per pF.

0: 50 counts/0.1 pF
1: 50 counts/0.2 pF
2: 50 counts/0.3 pF
3: 50 counts/0.4 pF

Also I found in the Design Guide spreadsheet (launched from EZClick) that there a power consumption calculator which takes the number and size of buttons into account when calculating power consumption.