#include <FreqCount.h>

//the baseline frequency of the main search coil
unsigned long baseLine = 0;

//Pins red, green and blue LEDs are attached to.
const int bluePin = A2;
const int greenPin = A4;
const int redPin = A5;
const int buzzerPin = 12;


void setup() {
  //set our LED pins as outputs
  pinMode(redPin,OUTPUT);
  pinMode(greenPin,OUTPUT);
  pinMode(bluePin,OUTPUT);
  pinMode(buzzerPin,OUTPUT);
  //Flash a sequence to test the LEDs and show we are starting up  
  digitalWrite(redPin,HIGH);
  delay(200);
  silence();
  digitalWrite(greenPin,HIGH);
  delay(200);
  silence();
  digitalWrite(bluePin,HIGH);
  delay(200);
  silence();

  //Read out baseline frequency count, 100ms intervals
  FreqCount.begin(100);
  while(!FreqCount.available())
  {
    delay(10);
  }
  baseLine = FreqCount.read();

  if(baseLine > 10000)
  {
    //Green, we started up OK
    digitalWrite(greenPin,HIGH);  
  }
  else
  {
    //Red, something went wrong, we didn't get a sensible count
    digitalWrite(redPin,HIGH);
  }
  delay(1000);

  silence();
}


void loop() {
  //no sample ready yet, exit.
  if (!FreqCount.available()) {
    return;
  }
  //Read how many pulses in 100 milliseconds
  unsigned long count = FreqCount.read();
  
  long difference =  baseLine - count;
  difference = abs(difference);
  
  //Difference is large, turn on the RED led
  if(difference > 5)
  {
    digitalWrite(greenPin,LOW);
    digitalWrite(bluePin,LOW);
    digitalWrite(redPin,HIGH);
    digitalWrite(buzzerPin,HIGH);
  }
  else if(difference > 2)  //medium difference, green
  {
    digitalWrite(greenPin,HIGH);
    digitalWrite(bluePin,LOW);
    digitalWrite(redPin,LOW);
    digitalWrite(buzzerPin,HIGH);
  }
  else if(difference > 1) //small difference, blue.
  {
    digitalWrite(greenPin,LOW);
    digitalWrite(bluePin,HIGH);
    digitalWrite(redPin,LOW);
    digitalWrite(buzzerPin,HIGH);
  }
  else
  {
    silence(); //no difference, turn off all LEDs
    digitalWrite(buzzerPin,LOW);
  }

  //Auto-adjust our baseline
  if(count > baseLine)
  {
    baseLine +=1;
  }
  else if (count < baseLine)
  {
     baseLine -= 1;
  }
}

  //Turn off all output pins
  void silence()
  {
    digitalWrite(redPin,LOW);
    digitalWrite(greenPin,LOW);
    digitalWrite(bluePin,LOW);
  }