/*
 *
 * LunaMod for Arduino & Attiny45
 * Remix by Rob Miles
 * Tacoma, WA August 8th 2011
 * 
 * I saw the original project in Make vol. 26
 * by Brian McNamara
 * Brian's was running on a PicAxe and I only have attiny45s so.......
 *
 * The freqout section where the real magic happens is from Paul Badger's synth code on the main Arduino site
 * 
 * I kept this pretty straight forward but with an Arduino this could get a lot more complicated if you like
 * Even on an attiny45 if you use you add a button to the led pin you coud sneak in more effects
 *
 */

#define frequencyPot   0                              //frequency pot tied to pin 15 which is A1
#define tempoPot       1                              //tempo pot tied to pin 16 which is A2
#define buttonPin      9                              //programming button tied to pin 17 which is A3
#define ledPin         10                             //status led tied to pin 18 which is A4
#define speakerPin     11                             //speaker or output pin 19 whish is A5
                                                      //if you use a speaker it should be at least a 16 ohm speaker an should have a 
                                                      //resistor, maybe 200ohm to 1K ohm, between the negative lead and ground.
                                                      //a potentiometer would be even better.

int currentStep = 0;                                  //this is just to track which tone in memory we are currently playing

int steps[] = {500,500,100,100,100,100,100,100,                    // this is our tone storage areae
               100,100,100,100,100,100,100,100,                     //I used 64 tones or 8 tones per beat
               500,500,100,100,100,100,100,100,                     //you can change these manually and experiment if you like
               100,100,100,100,100,100,100,100,     
               500,500,100,100,100,100,100,100,
               100,100,100,100,100,100,100,100,
               500,500,100,100,100,100,100,100,
               100,100,100,100,100,100,100,100};

int tempo = 0;                                      //tempo or speed between tones
int duration = 0;                                   //how long each of the 64 tones plays
int frequency = 0;                                  //current tone
int pitchval = 1;

void setup()                                        //set up your pins....
{ 
  pinMode (frequencyPot, INPUT); 
  pinMode (tempoPot, INPUT); 
  pinMode (buttonPin, INPUT);
  digitalWrite(buttonPin, HIGH);
  
  pinMode (ledPin, OUTPUT);               
  pinMode (speakerPin, OUTPUT);  

} 

void loop()
{


  for (int i=0; i<63; i++)                         //64 individual notes played
  { 
    
  currentStep = i;                                 //save our current position in the loop for later
    
  if (i == 0 || i == 16 || i == 32 || i == 48){    //keep track of the beat on the led
  digitalWrite(ledPin, HIGH);}
  
  if (i == 7 || i == 23 || i == 39 || i == 55){    //keep track of the beat on the led
  digitalWrite(ledPin, LOW);}
  
  
  
  
                                
  if (digitalRead(buttonPin) == LOW)               //is the program button being pressed
    {                                              //if so lets write a new tone the this location
      
    steps[currentStep] = (analogRead(frequencyPot));  //read the frequency pot and set the new tone
    freqout (steps[currentStep], duration);           //set the parameters for frequout below and play it
    freqout (steps[currentStep]+64, duration);       //play another tone a little bit different than the original to give
                                                      //it a little more depth. this can be changed to your liking
    freqout (steps[currentStep]+128, duration);       //play another tone a little bit different than the original to give
                                                      //it a little more depth. this can be changed to your liking

    }
    
    else {                                            //else play the tone
      
    freqout (steps[currentStep], duration);           //set the parameters for frequout below and play it
    freqout (steps[currentStep]+64, duration);       //play another tone a little bit different than the original to give
                                                      //it a little more depth. this can be changed to your liking
    freqout (steps[currentStep]+128, duration);       //play another tone a little bit different than the original to give
                                                      //it a little more depth. this can be changed to your liking

                                                      
  }
    tempo = (analogRead(tempoPot)/4);                    //read the tempo pot
    duration = tempo/8;                                   //set the individual tone durations
    delay(tempo);                                         //wait a bit
}
}


void freqout(int freq, int t) 
{ 
  int hperiod;    
  long cycles, i; 

  hperiod = (500000 / ((freq - 7) * pitchval));             

  cycles = ((long)freq * (long)t) / 1000;    

  for (i=0; i<= cycles; i++)
  {  
    digitalWrite(speakerPin, HIGH);  
    delayMicroseconds(hperiod); 
    digitalWrite(speakerPin, LOW);  
    delayMicroseconds(hperiod - 1);
  } 
}