int input=A0; //The word “input” now stands for the value “A0”

int LED=13; //”LED” now stand for the value 13

int sensorvalue=0; //Variable for the sensorvalue with 0 as starting value

void setup()

{ //The setup begins here

pinMode (LED,OUTPUT); //The pin 13 connected to the LED is defined as an output

}

void loop()

{ //The loop part begins here

sensorvalue= analogRead(input); //The voltage at the potentiometer is read

//out and gets saved as a number between 0 and 1023 under “sensorvalue”

digitalWrite (LED,HIGH); //Turn on LED

delay(sensorvalue); //The value, which is saved under “sensorvalue” defines

//how long the LED will light up (milliseconds)

digitalWrite(LED, LOW); //Turn off LED

delay(sensorvalue); 

} 

 Arduino Starter Kit example
 Project 13  - Touch Sensor Lamp

 This sketch is written to accompany Project 13 in the
 Arduino Starter Kit

 Parts required:
 1 Megohm resistor
 metal foil or copper mesh
 220 ohm resistor
 LED

 Software required :
 CapacitiveSensor library by Paul Badger
 http://www.arduino.cc/playground/Main/CapacitiveSensor

 Created 18 September 2012
 by Scott Fitzgerald

 http://www.arduino.cc/starterKit

 This example code is part of the public domain
 */

// import the library (must be located in the
// Arduino/libraries directory)
#include <CapacitiveSensor.h>

// create an instance of the library
// pin 4 sends electrical energy
// pin 2 senses senses a change
CapacitiveSensor capSensor = CapacitiveSensor(4, 2);

// threshold for turning the lamp on
int threshold = 1000;

// pin the LED is connected to
const int ledPin = 12;


void setup() {
  // open a serial connection
  Serial.begin(9600);
  // set the LED pin as an output
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // store the value reported by the sensor in a variable
  long sensorValue = capSensor.capacitiveSensor(30);

  // print out the sensor value
  Serial.println(sensorValue);

  // if the value is greater than the threshold
  if (sensorValue > threshold) {
    // turn the LED on
    digitalWrite(ledPin, HIGH);
  }
  // if it's lower than the threshold
  else {
    // turn the LED off
    digitalWrite(ledPin, LOW);
  }

  delay(10);
}