TouchPin

Arduino Library for simple touch button functionality

Status:

Still alpha. Usage can change anytime. But working pretty well, though ;) Tested only using TI TM4C123G Launchpad and Energia IDE (Andruino clone).

Usage:

#include "TouchPin.h"

TouchPin button( 2 );

void setup() {

	button.calibrate();
}

void loop() {

	if( button.push() ) {

		// DO STUFF
	}

	if( button.hold() ) {

		// DO STUFF
	}

}

For more USAGE see TouchPin.h

Schematics

-------+
       |
   pin +----+--------(PAD)
       |    |
       |   [ ] 1MΩ
       |    |
   gnd +----+
       |
-------+

Working

The pin is switched to output and the PAD is loaded capacitive. Then the pin is switched to open input and the PAD is discharged via the resistor.

The discharging takes a small amount of time which is dependant on the capacity of the PAD. This capacity is increased when you touch the PAD. This time is measured and taken as input for come comfort function.