arduino/wifi-mqtt-esp8266-oled-nohttp/wifi-mqtt-esp8266-oled-nohttp.ino

#include <DHT.h>//调用dht11驱动库
#include <ESP8266WiFi.h>
#include <PubSubClient.h>

#include "SSD1306Wire.h"

const int I2C_ADDR = 0x3c;  // oled屏幕的I2c地址
#define SDA_PIN D4           // SDA引脚，默认gpio4(D2)
#define SCL_PIN D5           // SCL引脚，默认gpio5(D1)
SSD1306Wire oled(I2C_ADDR, SDA_PIN, SCL_PIN);

#define DHTPIN D1 //说明数据接口为8266开发板的D4口，也可以写为#define DHTPIN 2既8266芯片的IO口2
#define DHTTYPE DHT11//说明使用的模块是DHT11
DHT dht(DHTPIN,DHTTYPE);//DHT11初始化

//定义浮点类型变量保存测量值
float Temperature;
float Humidity;
//定义WIFI信息
const char* ssid = "free";  // Enter SSID here
const char* password = "452131wW";  //Enter Password here


// MQTT代理
const char *mqtt_broker = "47.242.184.139";
const char *topic = "/device/esp8266/004";
const char *mqtt_username = "admin";
const char *mqtt_password = "publish452131wW452131wW$";
const int mqtt_port = 1883;

 
WiFiClient espClient;
PubSubClient client(espClient);

            
void setup() {    
  pinMode(D2, OUTPUT);
  digitalWrite(D2,HIGH);//IO口2设置为高电平，点亮数字2口LED
  //digitalWrite(D2,LOW);//IO口2设置为高电平，点亮数字2口LED
  Serial.begin(115200);
  delay(100);
  dht.begin();              
  Serial.println("Connecting to ");
  Serial.println(ssid);
  //connect to your local wi-fi network
  WiFi.begin(ssid, password);
  //check wi-fi is connected to wi-fi network
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected..!");
  Serial.print("Got IP: ");  Serial.println(WiFi.localIP());


  //mqtt init
  //连接到mqtt代理
  client.setServer(mqtt_broker, mqtt_port);
  client.setCallback(callback);
  while (!client.connected()) {
      String client_id = "esp8266-client-";
      client_id += String(WiFi.macAddress());
      Serial.printf("The client %s connects to the public mqtt broker\n", client_id.c_str());
      if (client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {
          Serial.println("Public emqx mqtt broker connected");
      } else {
          Serial.print("failed with state ");
          Serial.print(client.state());
          delay(2000);
      }
  }
  // 发布和订阅
  // client.publish(topic, "hello emqx");
  client.subscribe(topic);

  /* 2. oled屏幕初始化 */
  oled.init();
  oled.flipScreenVertically();  // 设置屏幕翻转
  oled.setContrast(255);        // 设置屏幕亮度
  drawRect();                   // 测试屏幕显示
  oled.clear();
  oled.display();  // 清除屏幕
}
void loop() {
  //mqtt
  client.loop();

  delay(10000);
  Temperature = dht.readTemperature(); // Gets the values of the temperature
  Humidity = dht.readHumidity(); // Gets the values of the humidity 
  //mqtt发布消息
  Serial.println("------------mqtt publish start-----------");
  if (WiFi.status() == WL_CONNECTED) {
    if(client.connected()){
      String sendStr = String(Temperature)+" "+String(Humidity);
      String wendu = String("Tem:")+String(Temperature);
      String shidu = String("Hum:")+String(Humidity);

      Serial.println(sendStr);
      client.publish(topic,sendStr.c_str());

      oled.clear();
      oled.setFont(ArialMT_Plain_16);        // 设置字体
      oled.drawString(0, 0, wendu);  // 将要显示的文字写入缓存
      oled.drawString(0, 20,shidu);  // 将要显示的文字写入缓存
      oled.drawString(0, 40,sendStr);  // 将要显示的文字写入缓存
      oled.display();                        // 将缓存里的文字在屏幕上显示
      
    }else{
      Serial.println(client.state());
      String client_id = "esp8266-client-";
      client_id += String(WiFi.macAddress());
      Serial.printf("The client %s connects to the public mqtt broker\n", client_id.c_str());
      if(client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {
        Serial.println("Public emqx mqtt broker connected");
        client.subscribe(topic);
      }else{
          Serial.print("failed with state ");
          Serial.print(client.state());
        }  
    }
  }
  Serial.println("------------mqtt publish end-----------");
}

void callback(char *topic, byte *payload, unsigned int length) {
  Serial.println("-----------callback------------");
  Serial.print("Message arrived in topic:");
  Serial.println(topic);
  Serial.print("Message:");
  for (int i = 0; i < length; i++) {
      Serial.print((char) payload[i]);
  }
  Serial.println();
  Serial.println("-----------callback------------");
}

void drawRect(void) {
  for (int16_t i = 0; i < oled.getHeight() / 2; i += 2) {
    oled.drawRect(i, i, oled.getWidth() - 2 * i, oled.getHeight() - 2 * i);
    oled.display();
    delay(50);
  }
}