#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 20, 4);  // I2C address 0x27, 20 columns and 4 rows

const int pirPin = 23;   // PIR motion sensor output pin
const int ledPin = 2;   // LED pin
const int ntcPin = 34;   // Analog pin for NTC temperature sensor

void setup() {
  Serial.begin(115200);
  pinMode(pirPin, INPUT);
  pinMode(ledPin, OUTPUT);
  
  lcd.begin(20, 4);        // initialize the lcd 
  lcd.init();
  lcd.backlight();
  lcd.clear();
}

void loop() {
  int motionState = digitalRead(pirPin);

  if (motionState == HIGH) {
    // Motion detected
    float temperature = readTemperature();
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Temperature: ");
    lcd.print(temperature);
    lcd.print(" C");
    if (temperature < 10.0) {
      digitalWrite(ledPin, HIGH);
      lcd.setCursor(0, 1);
      lcd.print("LED On");
    } else {
      digitalWrite(ledPin, LOW);
    }

    // Wait for 5 seconds (motion sensor delay time)
    delay(5000);

  } else {
    // No motion
    digitalWrite(ledPin, LOW);
    lcd.clear();
  }
}

float readTemperature() {
  const float BETA = 3950; // should match the Beta Coefficient of the thermistor
  // Read analog value from NTC temperature sensor
  int analogValue = analogRead(ntcPin);
  // Convert analog value to temperature in Celsius
  float T2=273.15+25;
  float vol=(float)(analogValue * 3.3 / 4096);
  float Rt=vol*10000/(3.3-vol);
  float Celsius=(float)1/(1/T2+log(Rt/10000)/BETA)-273.16;
  return Celsius;
}