Input/Output Coincidence

Description:

For this week's assignment, I built a mixer with three units that control three tones that are played in sequence. Each unit consists of a photocell and an LED. If a finger is held above a unit, the led flashes and the tone that corresponds to the unit is played in the sequence; otherwise, the tone is silent. For example, if the finger arrangement was {finger, finger, empty}, the mixer would play and flash {tone, tone, silent}.

Materials:

1 Arduino Uno

1 Solderless breadboard

3 LEDs

3 Photocells

1 Piezo buzzer

Code:

int ledPinA = 11;

int ledPinB = 10;

int ledPinC = 9;

int pcPinA = A0;

int pcPinB = A1;

int pcPinC = A2;

int speakerPin = 3;

boolean playA = false;

boolean playB = false;

boolean playC = false;

int pcPinAVal = 0;

int pcPinBVal = 0;

int pcPinCVal = 0;

int shiftValue = 30;

int delayValue = 50;

// note names and their corresponding half-periods  

byte names[] ={ 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'C'};  

int tones[] = { 1915, 1700, 1519, 1432, 1275, 1136, 1014, 956};

int count = 0;

int pcPinCurrent = 0;

void setup() {

  pinMode(ledPinA, OUTPUT);

  pinMode(ledPinB, OUTPUT);

  pinMode(ledPinC, OUTPUT);

  pinMode(pcPinA, INPUT); 

  pinMode(pcPinB, INPUT);

  pinMode(pcPinC, INPUT);

  pinMode(speakerPin, OUTPUT);

  Serial.begin(9600);

  Serial.println("ready");

}

void processPin(int* pcPin, int* pcPinPrevious, boolean* play, int* ledPin, byte note) {

  pcPinCurrent = analogRead(*pcPin);

  if(pcPinCurrent < *pcPinPrevious - shiftValue) {

    *play = true;

  }

  if(pcPinCurrent > *pcPinPrevious + shiftValue) {

    *play = false;

  }

  *pcPinPrevious = pcPinCurrent;

  if(*play) {

    analogWrite(*ledPin, 255);

    for (count=0;count<=8;count++) {  // look for the note

      if (names[count] == note) {  // ahh, found it

        for( int i=0; i<50; i++ ) {   // play it for 50 cycles

          digitalWrite(speakerPin, HIGH);

          delayMicroseconds(tones[count]);

          digitalWrite(speakerPin, LOW);

          delayMicroseconds(tones[count]);

        }

      }

    }

    analogWrite(*ledPin, 0);

  } else {

    delay(150);

  }

}

void loop() {

  processPin(&pcPinA, &pcPinAVal, &playA, &ledPinA, 'a');

  delay(delayValue);

  processPin(&pcPinB, &pcPinBVal, &playB, &ledPinB, 'c');

  delay(delayValue);

  processPin(&pcPinC, &pcPinCVal, &playC, &ledPinC, 'd');

  delay(delayValue);

}

Images:

http://i44.tinypic.com/2lwswuq.jpg