#include <WiFi.h>  
#include <PubSubClient.h>  
#include <DHT.h>  
#include <Wire.h>  
#include <LiquidCrystal_I2C.h>  
  
// 定义引脚  
#define DHTPIN 12     // DHT22数据引脚连接到ESP32的GPIO12  
#define DHTTYPE DHT22 // DHT 22 (AM2302)  
#define LCD_ADDR 0x27 // I2C地址，根据你的LCD模块可能有所不同  
#define LED_BLUE 23   // 蓝色LED引脚  
#define LED_RED 22    // 红色LED引脚  
#define RELAY_PIN 21  // 继电器引脚  
  
// WiFi和MQTT设置  
const char* ssid = "1";  
const char* password = "1234567890";  
const char* mqtt_server = "broker.emqx.io";  
const char* topic = "esp32/qm";  
const int mqtt_port = 1883;  
const char* mqtt_username = "lq196";  
const char* mqtt_password = "lq196";  
  
// 创建DHT实例  
DHT dht(DHTPIN, DHTTYPE);  
  
// 创建LCD实例  
LiquidCrystal_I2C lcd(LCD_ADDR, 16, 2);  
  
// 创建PubSubClient实例  
WiFiClient espClient;  
PubSubClient client(espClient);  
  
// 温湿度阈值  
const float temp_low_threshold = 25.0;  
const float temp_high_threshold = 38.0;  
  
void setup_wifi() {  
  delay(10);  
  WiFi.begin(ssid, password);  
  
  while (WiFi.status() != WL_CONNECTED) {  
    delay(500);  
    Serial.print(".");  
  }  
  
  Serial.println("");  
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");  
  Serial.println(WiFi.localIP());  
}  
  
void callback(char* topic, byte* payload, unsigned int length) {  
  // 打印主题和负载  
  Serial.print("Received message on topic: ");  
  Serial.println(topic);  
  Serial.print("Payload: ");  
  for (unsigned int i = 0; i < length; i++) {  
    Serial.print((char)payload[i]);  
  }  
  Serial.println();  
}  
  
void reconnect() {  
  while (!client.connected()) {  
    Serial.print("Attempting MQTT connection...");  
    String clientId = "esp32-client-";  
    clientId += WiFi.macAddress();  
    if (client.connect(clientId.c_str(), mqtt_username, mqtt_password)) {  
      Serial.println("connected");  
      client.publish(topic, "ESP32 connected");  
      client.subscribe(topic);  
    } else {  
      Serial.print("failed, rc=");  
      Serial.print(client.state());  
      Serial.println(" try again in 5 seconds");  
      delay(5000);  
    }  
  }  
}  
  
void setup() {  
  // 初始化串口通信  
  Serial.begin(115200);  
  
  // 初始化DHT传感器  
  dht.begin();  
  
  // 初始化LCD  
  lcd.init();  
  lcd.backlight();  
  lcd.setCursor(0, 0);  
  lcd.print("Initializing...");  
  
  // 初始化LED和继电器  
  pinMode(LED_BLUE, OUTPUT);  
  pinMode(LED_RED, OUTPUT);  
  pinMode(RELAY_PIN, OUTPUT);  
  
  // 初始化WiFi  
  setup_wifi();  
  
  // 初始化MQTT客户端  
  client.setServer(mqtt_server, mqtt_port);  
  client.setCallback(callback);  
}  
  
void loop() {  
  // 检查WiFi连接  
  if (!WiFi.isConnected()) {  
    setup_wifi();  
  }  
  
  // 检查MQTT连接  
  if (!client.connected()) {  
    reconnect();  
  }  
  client.loop();  
  
  // 读取DHT传感器数据  
  float humidity = dht.readHumidity();  
  float temperature = dht.readTemperature();  
  
  // 检查是否读取失败，并显示错误信息  
  if (isnan(humidity) || isnan(temperature)) {  
    Serial.println("Failed to read from DHT sensor!");  
    return;  
  }  
  
  // 更新LCD显示  
  lcd.clear();  
  lcd.setCursor(0, 0);  
  lcd.print("T:");  
  lcd.print(temperature);  
  lcd.print("C  H:");  
  lcd.print(humidity);  
  lcd.println("%");  
  
  // 更新LED和继电器状态  
  digitalWrite(LED_BLUE, temperature < temp_low_threshold ? HIGH : LOW);  
  digitalWrite(LED_RED, temperature > temp_high_threshold ? HIGH : LOW);  
  digitalWrite(RELAY_PIN, temperature < temp_low_threshold ? HIGH : LOW);  
  
  // 发布温湿度数据到MQTT  
  char msg[50];  
  snprintf(msg, sizeof(msg), "temp=%.1f&humidity=%.1f", temperature, humidity);  
  client.publish(topic, msg);  
  
  // 延时1秒  
  delay(1000);  
}