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Physical Pixel

This example example uses the Arduino board to receive data from the computer. The Arduino boards turns on an LED when it receives the character 'H', and turns off the LED when it receives the character 'L'.

The data can be sent from the Arduino serial monitor, or another program like Processing (see code below), Flash (via a serial-net proxy), PD, or Max/MSP.

Hardware Required

  • Arduino Board
  • Analog Sensor (potentiometer, photocell, FSR, etc.)

Software Required

Circuit

Attach an LED to pin 13. The long leg, or anode, goes to pin 13. The short leg, or cathode, goes to ground. You can also use the built-in LED on most Arduino boards.

click the image to enlarge

image developed using Fritzing. For more circuit examples, see the Fritzing project page

Schematic

click the image to enlarge

Code

/*
  Physical Pixel
 
 An example of using the Arduino board to receive data from the
 computer.  In this case, the Arduino boards turns on an LED when
 it receives the character 'H', and turns off the LED when it
 receives the character 'L'.
 
 The data can be sent from the Arduino serial monitor, or another
 program like Processing (see code below), Flash (via a serial-net
 proxy), PD, or Max/MSP.
 
 The circuit:
 * LED connected from digital pin 13 to ground
 
 created 2006
 by David A. Mellis
 modified 30 Aug 2011
 by Tom Igoe and Scott Fitzgerald
 
 This example code is in the public domain.

 http://www.arduino.cc/en/Tutorial/PhysicalPixel
 */


const int ledPin = 13; // the pin that the LED is attached to
int incomingByte;      // a variable to read incoming serial data into

void setup() {
  // initialize serial communication:
  Serial.begin(9600);
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // see if there's incoming serial data:
  if (Serial.available() > 0) {
    // read the oldest byte in the serial buffer:
    incomingByte = Serial.read();
    // if it's a capital H (ASCII 72), turn on the LED:
    if (incomingByte == 'H') {
      digitalWrite(ledPin, HIGH);
    }
    // if it's an L (ASCII 76) turn off the LED:
    if (incomingByte == 'L') {
      digitalWrite(ledPin, LOW);
    }
  }
}

/* Processing code for this example
 
 // mouseover serial
 
 // Demonstrates how to send data to the Arduino I/O board, in order to
 // turn ON a light if the mouse is over a square and turn it off
 // if the mouse is not.
 
 // created 2003-4
 // based on examples by Casey Reas and Hernando Barragan
 // modified 30 Aug 2011
 // by Tom Igoe
 // This example code is in the public domain.

 
 
 import processing.serial.*;
 
 float boxX;
 float boxY;
 int boxSize = 20;
 boolean mouseOverBox = false;
 
 Serial port;
 
 void setup()  {
 size(200, 200);
 boxX = width/2.0;
 boxY = height/2.0;
 rectMode(RADIUS);
 
 // List all the available serial ports in the output pane.
 // You will need to choose the port that the Arduino board is
 // connected to from this list. The first port in the list is
 // port #0 and the third port in the list is port #2.
 println(Serial.list());
 
 // Open the port that the Arduino board is connected to (in this case #0)
 // Make sure to open the port at the same speed Arduino is using (9600bps)
 port = new Serial(this, Serial.list()[0], 9600);
 
 }
 
 void draw()
 {
 background(0);
 
 // Test if the cursor is over the box
 if (mouseX > boxX-boxSize && mouseX < boxX+boxSize &&
 mouseY > boxY-boxSize && mouseY < boxY+boxSize) {
 mouseOverBox = true;  
 // draw a line around the box and change its color:
 stroke(255);
 fill(153);
 // send an 'H' to indicate mouse is over square:
 port.write('H');      
 }
 else {
 // return the box to it's inactive state:
 stroke(153);
 fill(153);
 // send an 'L' to turn the LED off:
 port.write('L');      
 mouseOverBox = false;
 }
 
 // Draw the box
 rect(boxX, boxY, boxSize, boxSize);
 }
 
 
 */


/*
Max/MSP version 5 patch to run with this example:

----------begin_max5_patcher----------
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HQmlzh9eu7gjsjsEk7y0oWjiHoHm4aluYHGlueUmtiDuPy5B9Cv8fNc99Uc5
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.P0K+3peBt3NskC
-----------end_max5_patcher-----------
 
 
 */

Processing Code

Copy the Processing code from the code sample above. As you mouse over the center square, the LED on pin 13 should turn on and off. The Processing applet looks like this:

Mouse over the square to turn the LED on and off.

Max patch

The Max/MSP patch looks like the image below. Copy it from the code sample above and paste it into a new patch window.

See Also:

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