FSR Lab

Description

Use a FSR to control how high a ball is on a screen.

Materials

• 1x Light Emitting Diode (LED)
• 1x Resistor
• 1x Force Sensing Receptor

Audrino Code

/*
 * Resistive Sensor Input
 * Takes the input from a resistive sensor, e.g., FSR or photocell
 * Dims the LED accordingly, and sends the value (0-255) to the serial port
 */
int sensorPin = 0;  // select the input pin for the sensor
int ledPin = 11;    // select the output 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(sensorPin); // read the value from the sensor, 0-1023
  analogWrite(ledPin, val/4);  // analogWrite (dimming the LED) can be between 0-255
  Serial.println(val/4);       // writing the value to the PC via serial connection
}

Processing Code

/*
 * Arduino Ball Paint
 * (Arduino Ball, modified 2008)
 * ----------------------
 *
 * Draw balls randomly on the screen, size controlled by a device
 * on a serial port.  Press space bar to clear screen, or any
 * other key to generate fixed-size random balls.
 *
 * Receives an ASCII number over the serial port,
 * terminated with a carriage return (ascii 13) then newline (10).
 *
 * This matches what Arduino's " Serial.println(val)" function
 * puts out.
 *
 * Created 25 October 2006
 * copyleft 2006 Tod E. Kurt <tod@todbot.com
 * http://todbot.com/
 */
import processing.serial.*;
// Change this to the portname your Arduino board
String portname = "COM4";
Serial port;
String buf="";
int cr = 13;  // ASCII return   == 13
int lf = 10;  // ASCII linefeed == 10
void setup() {
  size(300,300);
  frameRate(10);
  smooth();
  background(40,40,40);
  noStroke();
  port = new Serial(this, portname, 9600);
}
void draw() {
}
void keyPressed() {
  if(key == ' ') {
    background(40,40,40);  // erase screen
  }
  else {
    int x = int(random(0,width));
    int y = int(random(0,height));
    drawball(x,y, 50);
  }
}
// draw balls
void drawball(int x, int y, int r) {
  for (int i=0; i<100; i++ ) {
    fill(255-i,i,240);
    ellipse(x,y,r,r);
  }

}

void liftball (int x, int r) {
  for (int i=0; i<100; i++) {
    fill(255-i,i,240);
    ellipse(150, 300-x, r, r);
  }
}

// called whenever serial data arrives
void serialEvent(Serial p) {
  int c = port.read();
  if (c != lf && c != cr) {
    buf += char(c);
  }
  if (c == lf) {
    int val = int(buf);
    println("val="+val);
    liftball(val,40);
    buf = "";
    background(40,40,40);  // erase screen
  }
}

Mechanical