// UH 5COM2004
// Practical 2 - Serial Monitor
// 2.3 - Photocell
// 
// Connect a photoresistor 
// LDR - light dependent resistor
// https://learn.adafruit.com/photocells 
// simulator LDR behaves in the opposite way

#include <LiquidCrystal_I2C.h>

#define LDR_PIN 4 // A0 on ESP32 DevKit
int ldrReading;
float voltage;

// LDR Characteristics
const float GAMMA = 0.7;
const float RL10 = 50;

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  // put your setup code here, to run once:
  // set the data rate for serial communication
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  // configure pinMode
  pinMode(LDR_PIN, INPUT);
  

  lcd.init();
  lcd.backlight();
}

void loop() {
  // put your main code here, to run repeatedly:

  // read the voltage on the LDR pin
  ldrReading = analogRead(LDR_PIN);
  voltage = ldrReading * (3.3/4095.0); // 12 bit precision

  // display the reading on the serial monitor
  Serial.print("A0: ");
  Serial.print(ldrReading);
  Serial.print("    V: ");
  Serial.println(voltage);

  lcd.setCursor(2, 0);
  lcd.print("A0: ");
  lcd.println(ldrReading);

  lcd.setCursor(2, 1);
  lcd.print("V :");
  lcd.print(voltage);

  // wait 1 second
  delay(1000);
}