Plane Flier

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DESCRIPTION
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Inspired by clemens.meyer’s Light Chaser game (http://courses.ischool.berkeley.edu/i262/f13/content/clemensmeyer/lab-4-fsrs-and-photocells-light-chaser-game) from assignment 4, I wanted to create a similar screen-to-photocell receptor interaction game. I created an airplane with one photocell on each wing, which when used with a background that has a gradient on it, will calculate the difference between photocell values to tell if you are banking the plane to the left or to the right. I set the piezzo to produce different notes depending on whether the plane is turning left, right, or maintaining a neutral wing position. 
 
My end goal was to have it interact with a visual I made in processing that would update the screen to match with the turning of the plane (moving tree line and a compass in the corner). It was working well before I set it up to talk to Arduino and then I started getting errors about invalid access of memory location which I haven’t yet been able to troubleshoot all the way.
 
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COMPONENTS
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1- Arduino Uno
1 - Breadboard
2 - Photocell Receptor
2 − 10k Ω Resistors
1 - Piezzo buzzer
assorted wires
cardboard
 
 
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ARDUINO CODE
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/** PLANE_OUT
 * (Jordan Arnesen, October 2013)
 *
 * Sends out controller values to the computer
 * for use in Plane_Flier program.
 *
 */
 
 
// analog inputs
int inPhotL = 0;  // PHOT input connected to pin 0 - left wing
int inPhorR = 1;  // PHOT input connected to pin 1 - right wing
 
// output
int buzz = 7; // piezzo output on pin 7
 
// values
int photL = 0;  // variable to store value from left wing Phot
int photR = 0;  // variable to store value from right wing Phot
int diff = 0;  // difference between L and R wing values
int count = 0; // space out the outputs to processing
 
 
void setup()
{
  Serial.begin(9600);  // open communication for Processing to read
  pinMode(buzz, OUTPUT);
}
 
void loop()
{
  photL = analogRead(inPhotL);
  photR = analogRead(inPhorR);
  
  diff = photL - photR;
  
 if (diff > 100) {
     digitalWrite(buzz, HIGH);
     delayMicroseconds(1915);        // note 'c'
     digitalWrite(buzz, LOW);
     delayMicroseconds(1915);
  }
  else if (diff < -100) {
      digitalWrite(buzz, HIGH);
        delayMicroseconds(956);     // note 'b'
        digitalWrite(buzz, LOW);
        delayMicroseconds(956);
  }
  //else {
        digitalWrite(buzz, HIGH);
        delayMicroseconds(1275);    // note 'g'
        digitalWrite(buzz, LOW);
        delayMicroseconds(1275);
  //}
  if (count > 200) {
    Serial.println(diff);
    count =0;
  }
  count += 1;
}