// Author:  Nien Lam
// Date:    10-06-2009
// Title:   Digital Photo Sensor Tone Generator 
// Descr:   Using a 4 photocells to capture a digital like signal, play tones within 2 octaves of the C major scale.

#include <Tone.h>

// Pins intputs for photocells
int p0Pin = 2; 
int p1Pin = 4; 
int p2Pin = 3; 
int p3Pin = 5; 

// Threshold of photocells to interpret as 0 or 1
int threshold0 = 150;
int threshold1 = 180;
int threshold2 = 160;
int threshold3 = 160;

// Duration of note
int duration = 500;

// Temp vairables
int reading[4] = {0};
int readingVal = 0;
int lastVal    = 0;

// Tone object
Tone tone; 

// Notes for 2 octaves of the C major scale
int notesC_Maj[] = { NOTE_C4, 
                     NOTE_C4, NOTE_D4, NOTE_E4, NOTE_F4, NOTE_G4, NOTE_A4, NOTE_B4, 
                     NOTE_C5, NOTE_D5, NOTE_E5, NOTE_F5, NOTE_G5, NOTE_A5, NOTE_B5, 
                     NOTE_C6 };


void setup() {
  Serial.begin(9600); 
  tone.begin(8);
}


void loop() {
  Serial.println(analogRead(p0Pin));
  Serial.println(analogRead(p1Pin));
  Serial.println(analogRead(p2Pin));
  Serial.println(analogRead(p3Pin));

  reading[0] = (analogRead(p0Pin) > threshold0) ? 0 : 1;
  reading[1] = (analogRead(p1Pin) > threshold1) ? 0 : 1;
  reading[2] = (analogRead(p2Pin) > threshold2) ? 0 : 1;
  reading[3] = (analogRead(p3Pin) > threshold3) ? 0 : 1;

  Serial.print(reading[3]);
  Serial.print(reading[2]);
  Serial.print(reading[1]);
  Serial.println(reading[0]);

  // Convert binary to decimcal value
  readingVal = (reading[0]) + (reading[1]*2) + (reading[2]*4) + (reading[3]*8); 
  Serial.println(readingVal);
   
  // Don't play any note for 0
  if (readingVal == 0) {
    delay(duration);
    return;  
  }

  lastVal = readingVal;

  // Play note
  tone.play(notesC_Maj[readingVal]);
  delay(duration);
  tone.stop();

  delay(50);
}