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

#define NTC_PIN 15          // Temperature sensor pin
#define LED_PIN 16          // LED pin
#define MOTION_PIN 13       // Motion sensor pin

LiquidCrystal_I2C lcd(0x27, 20, 4);  // I2C address may vary, please adjust based on your LCD

unsigned long previousTempReadTime = 0;
unsigned long previousMotionDetectionTime = 0;
float totalTemperature = 0.0;
int temperatureReadingsCount = 0;
bool motionDetected = false;

void setup() {
  Serial.begin(9600);
  pinMode(LED_PIN, OUTPUT);
  pinMode(MOTION_PIN, INPUT);
  pinMode(NTC_PIN, INPUT);
  lcd.init();
  lcd.backlight();
}

void loop() {
  unsigned long currentMillis = millis();

  // Read temperature sensor data every 0.5 seconds
  if (currentMillis - previousTempReadTime >= 500) {
    const float BETA = 3950; // Beta value for temperature sensor
    int analogValue = analogRead(NTC_PIN);
    float celsius = 1 / (log(1 / (4095.0 / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
    Serial.print("Temperature: ");
    Serial.println(celsius);

    // Print out temperature value and LED status
    Serial.print("LED Status: ");
    Serial.println(digitalRead(LED_PIN) == HIGH ? "On" : "Off");

    previousTempReadTime = currentMillis;

    // When the OUT pin of the motion sensor is high, record temperature sensor data
    if (digitalRead(MOTION_PIN) == HIGH) {
      if (!motionDetected) {
        motionDetected = true;
        totalTemperature = 0.0;
        temperatureReadingsCount = 0;
      }
      digitalWrite(LED_PIN, HIGH);
      totalTemperature += celsius;
      temperatureReadingsCount++;
    } else {
      motionDetected = false;
    }
  }

  // When the OUT pin of the motion sensor goes low
  if (digitalRead(MOTION_PIN) == LOW) {
    if (currentMillis - previousMotionDetectionTime >= 9000) {
      // If the OUT pin goes low for more than 9 seconds, turn off the LED and clean the LCD display
      digitalWrite(LED_PIN, LOW);
      lcd.clear();
      totalTemperature = 0.0;
      temperatureReadingsCount = 0;
    } else if (currentMillis - previousMotionDetectionTime >= 3000) {
      // If the OUT pin of the motion sensor goes low, set the time interval for reading data to 3 seconds
      digitalWrite(LED_PIN, HIGH);
    } else if (currentMillis - previousMotionDetectionTime >= 3000) {
      // When the OUT pin of the motion sensor goes low, if the time exceeds 3 seconds, re-record temperature data
      totalTemperature = 0.0;
      temperatureReadingsCount = 0;
    }
  }

  // Calculate the average temperature when the OUT pin of the motion sensor is high and print on the LCD display
  if (motionDetected && temperatureReadingsCount > 0) {
    float averageTemperature = totalTemperature / temperatureReadingsCount;
    lcd.setCursor(0, 2);
    lcd.print("Avg Temp: ");
    lcd.print(averageTemperature);
  }
}