// include the library code:
#include <LiquidCrystal.h>
#include <TimerOne.h>


// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7,6,5,4,3,2);
long breath_rate_timer =0;
long breath_duty_timer =0;
int current_rate=0;
int current_duty=0;
int BPM_Pin = A0;    // select the input pin for the potentiometer
int Duty_Pin = A1;    // select the input pin for the potentiometer
int ledPin = 13;      // select the pin for the LED
int ValvePin = 12;
int SwitchPin = 11;
int BPM_Value = 0;  // variable to store the value for BPM
int Duty_Value =0;  // variable to store the value for duty cycle
boolean run_timer = 0;

void setup() {
  // declare the ledPin as an OUTPUT:
  pinMode(ledPin, OUTPUT); 
  pinMode(ValvePin, OUTPUT);
  pinMode(SwitchPin, INPUT);
  
  
  Serial.begin(9600);	// opens serial port, sets data rate to 9600 bps
  // set up the LCD's number of columns and rows: 
  lcd.begin(16, 2);
  lcd.setCursor(0,0);
  // Print a message to the LCD.
  lcd.print(" Breath-O-Matic ");
  Timer1.initialize(1000);         // initialize timer1, and set a 1 ms period  
  Timer1.attachInterrupt(callback);  // attaches callback() as a timer overflow interrupt
}

void callback()
{
  if (run_timer == 1)
  {
    // increment current rate count and reset if equal or larger
    if (current_rate++ >= breath_rate_timer)
    {
      current_rate=0;
      current_duty = 0;
      digitalWrite(ledPin,1);
      digitalWrite(ValvePin,1);
    }
    if (current_duty++ >= breath_duty_timer)
    {
      digitalWrite(ledPin, 0);
      digitalWrite(ValvePin,0);
    }
  }
  else
  {
    current_rate=0;
    current_duty=0;
    digitalWrite(ledPin,0);
    digitalWrite(ValvePin,0);
  }
}

void loop() {
  // read the value from the sensor:
  BPM_Value = analogRead(BPM_Pin);
  BPM_Value = map(BPM_Value, 0, 1023, 1, 180);
  Duty_Value = analogRead(Duty_Pin); 
  Duty_Value = map(Duty_Value, 0, 1023, 1, 99);
  breath_rate_timer = 60000/BPM_Value;
  breath_duty_timer = (breath_rate_timer*100)/(10000/Duty_Value); 
  run_timer= digitalRead(SwitchPin); 
  
  lcd.setCursor(0,1);
  lcd.print("BPM= ");
  lcd.print(BPM_Value);
  lcd.print(" DC= ");
  lcd.print(Duty_Value);
  lcd.print("  ");
}