Arduino Powered CPR Feedback Device © GPL3+

/*
CPR feedback Test sketch
-Using LCD to display results in real time
 */

#include <LiquidCrystal.h>

int pressurePin = 0; //pressure reading pin
int pressureRead; //for reading pressure pin
const int buttonPin = 8;  // pin for CPR count
unsigned long time; //to display time for compressions
const int pressGood = 10;
const int pressBad =  9;

int BPM; //final output calculated beats per min
float bpmCount; // to calculate BPM
float cprCount = 0;   // counter for the number of button presses, changed from int, changed from float
int buttonState = 0;         // current state of the button
int lastButtonState = 0;     // previous state of the button
int cprTotal = 0; //total of the 5 stored values
int cprCycle = 0; //keeps track of CPR cycle

int  timeSec, timeCPR, BPM_1; //calculating cpr time
float totalTime;
unsigned long timeBegin, timeEnd;

LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //LCD pins

void setup() {
 
  pinMode(buttonPin, INPUT); //CPR button
  pinMode(pressGood, OUTPUT); //for good release, led on Green
  pinMode(pressBad, OUTPUT); // for bad release, led on Red
  Serial.begin(9600); // start serial communication / uncomment to debug
  Serial.println("Begin CPR");
  lcd.begin(16, 2); //start LCD
  lcd.home();
  lcd.print("Begin CPR");
}

void loop() {
pressureRead = analogRead(pressurePin);
  time = millis(); //start time
  buttonState = digitalRead(buttonPin);
  if (buttonState != lastButtonState) {
       
    if (buttonState == HIGH) { //depth of at least 2in per AHA guidelines
      lcd.clear();
      lcd.home();
      cprCount++; //add 1 to the running total
      Serial.println(cprCount);
      lcd.setCursor(0,0);
      lcd.print("Count: ");
      lcd.setCursor(7,0);
      lcd.print(cprCount);
      lcd.setCursor(10,0);
      lcd.print("R: ");     //rate BPM
      
      if(cprCount == 1){
         timeBegin = millis(); //beginning time
      }
      
      }
     
    }
    //pressureRead = analogRead(pressurePin);
    if (pressureRead < 500){
        digitalWrite(pressGood, HIGH);
        digitalWrite(pressBad, LOW);
    }
    else if (pressureRead > 501){
        digitalWrite(pressBad, HIGH);
        digitalWrite(pressGood, LOW);
    }



     if (cprCount == 30){ // 30:2 ratio for CPR, 30 total
            cprCount = 0; //restart count
            timeEnd = millis(); //capture end time for set
            //Serial.println(timeEnd);
            totalTime = (timeEnd - timeBegin) / 1000; //convert Ms to seconds
            Serial.print("Total Time: ");
            Serial.println(totalTime);
            bpmCount = ( 30.0 / totalTime); //bpmCount = float
            Serial.print("BPM Count: ");
            Serial.println(bpmCount);
            BPM = (bpmCount * 60.0);
            Serial.print("Total time in sec: ");
            Serial.println(totalTime);
            lcd.home();
            lcd.print("Rate (BPM): ");
            lcd.setCursor(12,0);
            lcd.print(BPM);
            Serial.print("BPM is: ");
            Serial.println(BPM);
            lcd.setCursor(0,1);
            lcd.print("Total Time: ");
            lcd.setCursor(12,1);
            lcd.print(totalTime);
            cprCycle++;
            Serial.print("CPR Cycle #: ");
            Serial.println(cprCycle);
            if (cprCycle == 5){
                cprCycle = 0;
            }
            
     }
     
     if (cprCount > 5 && cprCount <= 30) {
         float rateTime = (millis() - timeBegin) / 1000; //changed int rateTime to unsigned long
         //Serial.println(rateTime);
         int rate = (cprCount / rateTime) * 60; //changed int to unsigned int
         //Serial.print("BPM is: ");
         //Serial.println(rate);
         
         if (rate >= 100 && rate <= 120 ){ //AHA guidelines 100-120 CPM
             lcd.setCursor(12,0);
             lcd.print("Good");
         }
         else {
             lcd.setCursor(12,0);
             lcd.print("----");
         }
     }

     
    // Delay
    delay(25); //changed from 50
  lastButtonState = buttonState;
}