#include <Wire.h>                
#include <Adafruit_GFX.h>        
#include <Adafruit_SSD1306.h>    //Adafruit library

// Define OLED display
#define OLED_RESET 4
Adafruit_SSD1306 display(OLED_RESET);


uint8_t ledBright1;
uint8_t ledBright2;
uint8_t ledBright3;
uint8_t ldrVal1;
uint8_t ldrVal2;
uint8_t ldrVal3;

ISR(ADC_vect)   {
    if (ADCSRA &= ~(1 << ADSC)) { // if ADSC is LOW then read ADC
        switch(ADMUX){
            case 0x40: { 
                ldrVal1 = ADC;
                //Serial.println(ldrVal1);
                ADMUX = 0x41;
                break;} 
            case 0x41: {
                ldrVal2= ADC;
                ADMUX = 0x42; 
                break;}
            case 0x42: { 
                ldrVal3 = ADC; 
                ADMUX = 0x40; 
                break;}}
                    }
    ADCSRA |= (1 << ADSC); // Start the next ADC conversion
}

//OCR1A ISR
ISR(TIMER1_COMPA_vect)
{
     OCR1A = ledBright1; // Yellow LED connected on PIN9
}

// OCR1B ISR
ISR(TIMER1_COMPB_vect)
{
     OCR1B = ledBright2; // Yellow LED connected on PIN10
}

uint8_t ldr2brightness(uint8_t ldr)
{
    return (ldr * 0.2492 + 1); // (255/1023) to convert 10-bit ADC to 8-bit PWM
}


void setup() {
    //Serial.begin(9600);
  
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.display();
  delay(2000);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0, 0);
  display.println("Please press the");
  display.println("blue button to");
  display.println("Turn ON");
  display.display();

  

  
  
  // Set Up ADC with prescalar 128
  ADCSRA = (1 << ADEN) | (1 << ADIE) | (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0); 
  ADCSRA |= (1 << ADSC); // Conversion start
  ADMUX = 0x40; 


  // Set up Timer1 PWM on OCR1A and OCR1B to control brightness of 2 Yellow LEDs
  // Mode-5 operation (TOP-0xFF-255) with Non-Inv Fast PWM
  TCCR1A |= (1 << COM1A1) | (1 << COM1B1) | (1 << WGM10); 
  TCCR1B |= (1 << WGM12) | (1 << CS12); // Prescalar-256
  TIMSK1 |= (1 << OCIE1A); // For CompA OCR1A interrupt
  TIMSK1 |= (1 << OCIE1B); // For CompB OCR1B interrupt
  DDRB |= (1 << PB1);
  PORTB |= (1 << PB1);
  DDRB |= (1 << PB2);
  PORTB |= (1 << PB2);

}

void loop() {
PORTB |= (1 << PB2);
delay(500);
PORTB &= ~(1 << PB2);
delay(500);

   ledBright1 = ldr2brightness(ldrVal1);
}