#include "I2Cdev.h"
#include <LiquidCrystal_I2C.h>

MPU6050 mpu;

const int heartRatePin = A0;
const int ledPins[] = {2, 3, 4, 5, 6, 7, 8, 9};
volatile int heartRate = 0;
int intensity = 0;
unsigned long previousMillis = 0;
const long interval = 500;  // Interval for updating the LED display

void setup() {
  Serial.begin(9600);
  for (int i = 0; i < 8; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
  
  // Configure timer interrupt
  Timer1.initialize(1000000);  // Set timer to 1 second
  Timer1.attachInterrupt(timerISR);  // Attach timer interrupt service routine
  
  // Enable ADC interrupt
  ADCSRA |= (1 << ADIE);
  sei();  // Enable global interrupts
}

ISR(ADC_vect) {
  heartRate = ADC;  // Read the ADC value
  intensity = map(heartRate, 0, 1023, 0, 255);  // Map heart rate to LED intensity
}

void timerISR() {
  // Trigger ADC conversion
  ADCSRA |= (1 << ADSC);
}

void loop() {
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
    
    // Update LED display
    int numLeds = map(heartRate, 0, 1023, 0, 8);
    for (int i = 0; i < 8; i++) {
      if (i < numLeds) {
        analogWrite(ledPins[i], intensity);
      } else {
        digitalWrite(ledPins[i], LOW);
      }
    }
  }
}