Assignment: Sensing PART II: Force sensors and photocells

Collaborators:

For this project, we used photo cells to measure light and force sensors to measure pressure. For my project I wanted to create a pong game controlled by alternative controllers, such as force or light.

 

The code for the arduino sends information about how much pressure is on the pad to the computer. The computer program (in processing) interprets this information and uses it to control the paddle.

 

/*

 * 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 = 11;   // 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);

  analogWrite(ledPin, val/4); // analogWrite can be between 0-255

}

The Processing code works as follows:

 

/*

 * Arduino Pong, By Sean Carey

 * I doubt anyone will care to copy it.

 * This program takes input from the Serial to control a virtual paddle on the

 * screen. It essentially works like pong. The code is modified from Arduino

 * Ball Paint by Tod E. Kurt 

 */

 

import processing.serial.*;

// Change this to the portname your Arduino board

String portname = "/dev/tty.usbserial-A70061U5"; // or "COM5"

Serial port;

String buf="";

int cr = 13;  // ASCII return   == 13

int lf = 10;  // ASCII linefeed == 10

int balla=2; //velocity of the ball in the x direciton

int ballb=2; //velocity of the ball in the y direction

int ballx=150; //position of the ball

int bally=100; //position of the bal

int h=0; // position of paddle

void setup() {

  size(300,150);

  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++ ) {

    ballx += balla;

    if (ballx > 295 || ballx<20 && bally< h+40 && bally>h){

     balla=-1*balla;

    }

    if (bally>145 || bally<5){

        ballb=-1*ballb;

      }

      

    if (ballx < -10){

     ballx=150;

     bally=100; 

    }

    bally += ballb;

    fill(255,255,255);

    ellipse(x,y,r,r);

  //}

 

 

}

// Draw paddle

void drawpaddle (int h){

  fill(204, 102, 0);

  rect(5, h, 5, 40);

}

 

 

// 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); 

    background(40,40,40);  // erase screen

    drawball(ballx,bally,10);

    drawpaddle(val);

    h=val;

    buf = "";

    

  }

 

}

My hope was to have one pot control the position of the paddle while the force sensor controlled how hard the ball was hit

 

For the second part of the project, I was curious to see how much force was required to click the mouse button, and if it varied between trackpad button and external mouse. Using the same arduino code from the pong program, i found some values for:

Macbook Trackpad Button: 340

Mighty Mouse Button: 630

Apple Desktop Bus Mouse Button: 240

 

I am surprised that the Mighty Mouse required so much force to click! My Apple Desktop Bus Mouse may have been worn in and therefore required less force to click. Still, the Mighty mouse required more than 2x the force for the trackpad button, and almost 3x the force for the old ADB mouse.