#include <DHT.h>

// 传感器引脚
#define MQ2_DIGITAL_PIN PA0
#define MQ2_ANALOG_PIN PA1
#define DHT22_PIN PB7  // 根据电路图，DHT22数据引脚连接到PB7

// LED引脚
#define GREEN_LED_PIN PB0
#define YELLOW_LED_PIN PB1
#define RED_LED_PIN PB2

// 阈值
#define LOW_THRESHOLD 650    
#define HIGH_THRESHOLD 950

// DHT22传感器
DHT dht(DHT22_PIN, DHT22);

// 温湿度变量
float temperature = 0;
float humidity = 0;
unsigned long lastDHTRead = 0;

void setup() {
  Serial.begin(115200);
  
  // 设置引脚
  pinMode(MQ2_DIGITAL_PIN, INPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(YELLOW_LED_PIN, OUTPUT);
  pinMode(RED_LED_PIN, OUTPUT);
  
  // 初始化DHT传感器
  dht.begin();
  
  Serial.println("气体和温湿度传感器启动");
  Serial.println("========================");
  delay(2000); // 给传感器启动时间
}

void loop() {
  // 读取气体传感器
  int gasDigital = digitalRead(MQ2_DIGITAL_PIN);
  int gasAnalog = analogRead(MQ2_ANALOG_PIN);
  
  // 每2秒读取一次温湿度
  if (millis() - lastDHTRead > 2000) {
    // 读取温湿度
    float h = dht.readHumidity();
    float t = dht.readTemperature();
    
    // 检查读数是否有效
    if (isnan(h) || isnan(t)) {
      Serial.println("DHT22读取失败! 检查连接");
    } else {
      humidity = h;
      temperature = t;
    }
    
    lastDHTRead = millis();
  }
  
  // 控制LED
  if (gasAnalog < LOW_THRESHOLD) {
    digitalWrite(GREEN_LED_PIN, HIGH);
    digitalWrite(YELLOW_LED_PIN, LOW);
    digitalWrite(RED_LED_PIN, LOW);
  } else if (gasAnalog < HIGH_THRESHOLD) {
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(YELLOW_LED_PIN, HIGH);
    digitalWrite(RED_LED_PIN, LOW);
  } else {
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(YELLOW_LED_PIN, LOW);
    digitalWrite(RED_LED_PIN, HIGH);
  }
  
  // 串口输出
  Serial.print("气体: ");
  Serial.print(gasAnalog);
  
  // 气体状态指示
  if (gasAnalog < LOW_THRESHOLD) {
    Serial.print(" (安全)");
  } else if (gasAnalog < HIGH_THRESHOLD) {
    Serial.print(" (警告)");
  } else {
    Serial.print(" (危险)");
  }
  
  Serial.print(" | 温度: ");
  Serial.print(temperature, 1);
  Serial.print("°C");
  Serial.print(" | 湿度: ");
  Serial.print(humidity, 1);
  Serial.println("%");
  
  delay(1000);
}