Description

Image zoom is controlled with the help of a potentiometer, to make the zooming process more intutive and natural.

Components Used 

 Arduino board

1 resistor 

1 potentiometer

Arduino Code 

/*
 * one pot fades one led
 * modified version of AnalogInput
 * by DojoDave <http://www.0j0.org>
 * http://www.arduino.cc/en/Tutorial/AnalogInput
 */
int potPin = 0;   // select the input pin for the potentiometer
int ledPin = 13;   // select the pin for the LED
int val = 0;      // variable to store the value coming from the sensor
void setup() {
  Serial.begin(9600);
}
void loop() {
  val = analogRead(potPin);    // read the value from the sensor, between 0 - 1024
  Serial.println(val/4);
  delay(100);
//  analogWrite(ledPin, val/4); // analogWrite can be between 0-255
}
 

Processing Code 

 //Srinivasan Ramaswamy
//Picture Zoomer
import processing.serial.*;

String portname = "COM7";
Serial port;
PImage img;
int w,h,sw,sh;
int counter=0;
int prevVal=0;
// Change this to the portname your Arduino board

String buf="";
int cr = 13;  // ASCII return   == 13
int lf = 10;  // ASCII linefeed == 10

void setup()
{
  size(1024,800);
  frameRate(30);
  // The background image must be the same size as the parameters
  // into the size() method. In this program, the size of "cute.jpg"
  // is 200 x 200 pixels.
  img = loadImage("cute.jpg");
  port = new Serial(this, portname, 9600);
}

void draw()
{
  image(img,0,0,width,height);
//  a = (a + 1)%(width+32);
//  stroke(226, 204, 0);
//  line(0, a, width, a-26);
//  line(0, a-6, width, a-32);
}

void keyPressed() {
  if(key=='+') { 
    width = width + 10;
    height = height + 10;
  }
  if(key=='-') { 
    width = width - 10;
    height = height - 10;
  }

//  drawImg();
}

void serialEvent(Serial p) {
  int c = port.read();
  if (c != lf && c != cr) {
    buf += char(c);
  }
  if (c == lf) {
    int val = int(buf);
    if (counter==0){
      int firstVal = val;
    }
    if (val>prevVal){
      w = val%10;
      h = val%10;
      width = width+w;
      height = height+h;
    }
    else if(val<prevVal){
      w = val%10;
      h = val%10;
  
      width = width-w;
      height = height-h;
    }
    print("val="+val);
    println(" prevVal="+prevVal);
    if (val!=prevVal){
      prevVal = val;
    }
//    int x = int(random(0,width));
//    int y = int(random(0,height));
//    drawball(x,y,val);
    buf = "";
//    background(40,40,40);  // erase screen
  }
}