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

// Pin Definitions
#define DHT22_PIN PA0 // DHT sensor data pin connected to PA0
#define FAN_PIN PA2   // Relay control pin connected to PA2
#define UP_PIN PA3    // Up button connected to PA3 (can change as needed)
#define DOWN_PIN PA4  // Down button connected to PA4 (can change as needed)
#define MOTION_SENSOR_PIN PA1 // PIR sensor data pin connected to PA1

DHT dht22(DHT22_PIN, DHT22);
LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 columns, and 2 rows

float threshhold = 80.0; // 80 F as the threshold temperature
bool fanOn = false;
int UP_lastState = HIGH;  // previous state of UP button
int UP_currentState;  
int DOWN_lastState = HIGH;  // previous state of DOWN button**Project Link:** https://wokwi.com/projects/408116783885922305?gh=1

Error message: /STMicroelectronics/tools/xpack-arm-none-eabi-gcc/13.2.1-1.1/bin/../lib/gcc/arm-none-eabi/13.2.1/../../../../arm-none-eabi/bin/ld: /sketch.ino.elf section `.rodata' will not fit in region `FLASH'
/STMicroelectronics/tools/xpack-arm-none-eabi-gcc/13.2.1-1.1/bin/../lib/gcc/arm-none-eabi/13.2.1/../../../../arm-none-eabi/bin/ld: region `FLASH' overflowed by 1576 bytes
collect2: error: ld returned 1 exit status

Error during build: exit status 1

int DOWN_currentState;  
bool motionDetected = false; // State of motion detection

void setup() {
  // Initialize serial communication
  Serial.begin(9600);

  // Initialize the DHT22 sensor
  dht22.begin();

  // Initialize the LCD
  lcd.init();
  lcd.backlight();
  lcd.clear();

  // Set pin modes
  pinMode(FAN_PIN, OUTPUT);       // Fan relay control pin
  pinMode(UP_PIN, INPUT_PULLUP);  // UP button with internal pull-up
  pinMode(DOWN_PIN, INPUT_PULLUP);// DOWN button with internal pull-up
  pinMode(MOTION_SENSOR_PIN, INPUT); // PIR motion sensor pin
}

void loop() {
  // Read temperature in Fahrenheit
  float tempF = dht22.readTemperature(true);

  // Read the state of the motion sensor
  motionDetected = digitalRead(MOTION_SENSOR_PIN);

  // Control the fan based on temperature and motion detection
  if (tempF >= threshhold && motionDetected) {
    if (!fanOn) { 
      fanOn = true;
      digitalWrite(FAN_PIN, HIGH); 
    }
  } else {
    if (fanOn) { 
      fanOn = false;
      digitalWrite(FAN_PIN, LOW); 
    }
  }

  // Read the state of the UP button to increase the threshold
  UP_currentState = digitalRead(UP_PIN);
  if (UP_currentState == LOW && UP_lastState == HIGH) { 
    threshhold += 1;
  }
  UP_lastState = UP_currentState;

  // Read the state of the DOWN button to decrease the threshold
  DOWN_currentState = digitalRead(DOWN_PIN);
  if (DOWN_currentState == LOW && DOWN_lastState == HIGH) { 
    threshhold -= 1;
  }  
  DOWN_lastState = DOWN_currentState;

  // Check if reading the temperature failed
  if (isnan(tempF)) {
    Serial.println("Failed to read from DHT22 sensor!");
  } else {
    // Display current temperature and threshold on LCD
    lcd.setCursor(0, 0);         // move cursor to (0, 0)
    lcd.print("Curr. Temp: ");
    lcd.print(tempF);
    lcd.print("F");

    lcd.setCursor(0, 1);         // move cursor to (0, 1)
    lcd.print("Threshhold: ");
    lcd.print(threshhold);
    lcd.print("F");
  }

  delay(1000); // Delay for readability
}