3 LED
3 Resistors
2 Potentiometers
Arduino Board
Breadboard
Wires

Arduino Code

/*

*  09/26/07

*  Tangible User Interfaces

*  Lab 4 Sensors: Force sensitive resistors and photocells

*  Eun Kyoung Choe

*/

// variables for input pin and control LED

  int analogInput = 3;

  int LEDpin1 = 13;

  int LEDpin2 = 12;

  int LEDpin3 = 11;

 

// variable to store the value

  int value = 0;

 

// a threshold to decide when the LED turns on

  int threshold = 512;

  void setup(){

// declaration of pin modes

  pinMode(analogInput, INPUT);

  pinMode(LEDpin1, OUTPUT);

  pinMode(LEDpin2, OUTPUT);

  pinMode(LEDpin3, OUTPUT);

   

// begin sending over serial port

  beginSerial(9600);

}

void loop(){

// read the value on analog input

  value = analogRead(analogInput);

// if value greater than threshold turn on LED

  if (value < threshold){

  digitalWrite(LEDpin1, LOW);

  digitalWrite(LEDpin2, LOW);

  digitalWrite(LEDpin3, LOW);  

}

else{

   digitalWrite(LEDpin1, HIGH);

   digitalWrite(LEDpin2, HIGH);

   digitalWrite(LEDpin3, HIGH);

}

// print out value over the serial port

  printInteger(value);

// and a signal that serves as seperator between two values

  printByte(10);

// wait for a bit to not overload the port

  delay(10);

}

Processing Code

/*

*   09/26/07

*  Tangible User Interfaces

*  Lab 4 Sensors: Force sensitive resistors and photocells

*  Eun Kyoung Choe

*

*  Reads the values which represent the state of a FSR sensor

*  from the serial port and draws a graphical representation.

*/

// importing the processing serial class

import processing.serial.*;

// definition of window size and framerate

  int xWidth = 500;

  int yHeight = 500;

  int fr = 30;

// attributes of the display

  boolean output = false;

 

// variables for serial connection, portname and baudrate have to be set

  Serial port;

  String portname = "/dev/tty.usbserial-A4001nXx"; 

  int baudrate = 9600;

  int value = 0;

  String buf="";

  int value1 = 0; 

// variables to draw graphics

  int x, y, cursorSize;

  int cnt = 6;

 

// hit the space key and erases the screen

void keyPressed(){

  if (key == ' '){

    background(153);

  }

}

void setup(){

 

  // set size and framerate

  size(xWidth, yHeight);

  background(153);

  frameRate(fr);

  // establish serial port connection     

  port = new Serial(this, portname, baudrate);

  println(port);

  noStroke();

  smooth();

}

void drawLDRState(){

 

  cnt = int(random(1,5));

  cursorSize = 5 + cnt*(value1/20); 

  x=int(random(0,500));

  y=int(random(0,500));

  float gray = value1/4;

  fill(gray,120);

  ellipse(x,y,cursorSize,cursorSize);

}

void serialEvent(int serial){

  if(serial!=10) {       

    buf += char(serial);         

    } else {

    value1 = int(buf);

    buf="";

    }

    if(output) println("LDR: "+value1);

}

void draw(){

  while(port.available() > 0){

        value = port.read();

        serialEvent(value);

    }

  drawLDRState();

}

Photo