6. 毕业设计温湿度监控系统（ESP8266 + DHT11 +OLED 实时上传温湿度数据给公网服务器并在OLED显示屏上显示实时温湿度）

硬件环境

1. ESP8266开发板一块；
2. DHT11温湿度传感器一个；
3. OLED 128*64分辨率显示屏幕一个；

硬件连线图入下所示：

软件环境

1. WiFi联网和HttpPost配置

参照我的另一篇博文，该博文中展示了如何建立PostHttpClient工程，修改后上传数据到公网服务器的Web服务器，
《5. ESP8266使用PostHttpClient例程上传数据给Web服务器后台》。

2. DHT11温湿度读取和OLED显示配置

参照我的另一篇博文，该博文中展示了如何使用ESP8266 NodeMCU开发板获取DHT11温湿度传感器并将数据显示在OLED显示屏上，《4. ESP8266通过OLED实时显示DHT11温湿度参数》。

3. Web服务器配置（用于接收HTTP数据请求）

• 如果服务器系统为windos，可以参照之前博文《树莓派+传感器+公网服务器 组件自己的物联网平台（三）WEB服务器配置》；

• 如果服务器系统是Ubuntu，可以根据本人的B站视频同步搭建，B站ID为张三编程分享，地址为：https://space.bilibili.com/243861879，该账号会实时更新服务器配置过程。

Web服务器环境搭建过程最为复杂，如果是小白可以根据B站视频的内容一步步来搭建。
代码的git将Web服务器的代码下载到本地，命令如下：

git clone git://116.198.42.221/ESP8266_IOT.git
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Use_Mysql目录下的代码就是Django工程的所有代码，下载后在服务器中运行，需要修改其中的mysql数据库相关信息

实验过程

1. ESP8266 NodeMCU完整代码

将下面代码编程上传到ESP8266 NodeMCU中，代码中只需要修改服务器地址和WiFi相关信息即可

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#include <DHT.h>                         // Include DHT library code

//begin********http head and define***************
#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>

#define SERVER_IP "116.198.42.221"  //这里是我的公网服务器的IP地址，这个需要修改

#ifndef STASSID
#define STASSID "WiFi name"
#define STAPSK  "WiFi password"
#endif
//end********http head and define***************
#define DHTPIN  14                    // DHT11 data pin is connected to ESP8266 GPIO14 (NodeMCU D5)
#define DHTTYPE DHT11                 // DHT11 sensor is used
DHT dht(DHTPIN, DHTTYPE);             // Configure DHT library

char temperature[] = "00.0";
char humidity[]    = "00.0";

// OLED FeatherWing buttons map to different pins depending on board.
// The I2C (Wire) bus may also be different.
#if defined(ESP8266)
  #define BUTTON_A  0
  #define BUTTON_B 16
  #define BUTTON_C  2
  #define WIRE Wire
#elif defined(ESP32)
  #define BUTTON_A 15
  #define BUTTON_B 32
  #define BUTTON_C 14
  #define WIRE Wire
#elif defined(ARDUINO_STM32_FEATHER)
  #define BUTTON_A PA15
  #define BUTTON_B PC7
  #define BUTTON_C PC5
  #define WIRE Wire
#elif defined(TEENSYDUINO)
  #define BUTTON_A  4
  #define BUTTON_B  3
  #define BUTTON_C  8
  #define WIRE Wire
#elif defined(ARDUINO_FEATHER52832)
  #define BUTTON_A 31
  #define BUTTON_B 30
  #define BUTTON_C 27
  #define WIRE Wire
#elif defined(ARDUINO_ADAFRUIT_FEATHER_RP2040)
  #define BUTTON_A  9
  #define BUTTON_B  8
  #define BUTTON_C  7
  #define WIRE Wire1
#else // 32u4, M0, M4, nrf52840 and 328p
  #define BUTTON_A  9
  #define BUTTON_B  6
  #define BUTTON_C  5
  #define WIRE Wire
#endif

Adafruit_SSD1306 display = Adafruit_SSD1306(128, 64, &WIRE);

void setup() {
  Serial.begin(9600);

  Serial.println("OLED FeatherWing test");
  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C); // Address 0x3C for 128x32
  //display.begin(SSD1306_SWITCHCAPVCC, 0x3D);  // initialize with the I2C addr 0x3D (for the 128x64)

  Serial.println("OLED begun");

  // Show image buffer on the display hardware.
  // Since the buffer is intialized with an Adafruit splashscreen
  // internally, this will display the splashscreen.
  display.display();
  delay(1000);

  // Clear the buffer.
  display.clearDisplay();
  display.display();

  Serial.println("IO test");

  pinMode(BUTTON_A, INPUT_PULLUP);
  pinMode(BUTTON_B, INPUT_PULLUP);
  pinMode(BUTTON_C, INPUT_PULLUP);

  // text display tests
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);


  dht.begin();                // Initialize the DHT library
  // Clear the display buffer.
  display.clearDisplay();


  display.setTextSize(1);
  display.setTextColor(WHITE, BLACK);
  display.setCursor(10, 5);
  display.print("DHT11 TEMPERATURE:");
  display.setCursor(19, 37);
  display.print("DHT11 HUMIDITY:");
  display.display();

  //begin************WiFi Setup*****************
  WiFi.begin(STASSID, STAPSK);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected! IP address: ");
  Serial.println(WiFi.localIP());
  //end************WiFi Setup*****************
}

void loop() {
  
  // Read humidity
  byte RH = dht.readHumidity();
  //Read temperature in degree Celsius
  byte Temp = dht.readTemperature();

  temperature[0] = Temp / 10 + '0';
  temperature[1] = Temp % 10 + '0';
  humidity[0]    = RH / 10   + '0';
  humidity[1]    = RH % 10   + '0';

  // print data on serial monitor
  Serial.printf("Temperature = %02u°C\r\n", Temp);
  Serial.printf("Humidity    = %02u %%\r\n\r\n", RH);
  
  // Clear the display buffer.
  display.clearDisplay();
  // print data on the SSD1306 display
  display.setTextSize(1);
  display.setTextColor(WHITE, BLACK);
  display.setCursor(10, 5);
  display.print("DHT11 TEMPERATURE:");
  display.setCursor(19, 37);
  display.print("DHT11 HUMIDITY:");
  display.display();
  display.setCursor(46, 20);
  display.print(temperature);
  display.setCursor(46, 52);
  display.print(humidity);
  display.drawRect(71, 20, 3, 3, WHITE);     // Put degree symbol ( ° )
  display.display();

  //begin********HttpPost wait for WiFi connection
  if ((WiFi.status() == WL_CONNECTED)) {

    WiFiClient client;
    HTTPClient http;

    Serial.print("[HTTP] begin...\n");
    // configure traged server and url
    http.begin(client, "http://" SERVER_IP "/IOT/add_environments"); //HTTP
    http.addHeader("Content-Type", "application/x-www-form-urlencoded");

    Serial.print("[HTTP] POST...\n");
    // start connection and send HTTP header and body
    String content = "temperatures=";
    String str2 = temperature;
    String str3 = "&humidity=";
    String str4 = humidity;
    String str5 = "&pressure=111";
    content.concat(str2);
    content.concat(str3);
    content.concat(str4);
    content.concat(str5);

    //const String content = "temperatures=" + temperature + "&humidity=" + humidity +"&pressure=111";
    int httpCode = http.POST(content);

    // httpCode will be negative on error
    if (httpCode > 0) {
      // HTTP header has been send and Server response header has been handled
      Serial.printf("[HTTP] POST... code: %d\n", httpCode);

      // file found at server
      if (httpCode == HTTP_CODE_OK) {
        const String& payload = http.getString();
        Serial.println("received payload:\n<<");
        Serial.println(payload);
        Serial.println(">>");
      }
    } else {
      Serial.printf("[HTTP] POST... failed, error: %s\n", http.errorToString(httpCode).c_str());
    }

    http.end();
  }
  //end********HttpPost wait for WiFi connection
  delay(5000);
}
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2. 服务器Web后台代码运行

使用git将代码下载到本地，修改一下settings.py文件中的数据库配置信息，进入Use_Mysql目录，运行如下命令：

cd Use_Mysql/
sudo python3 manage.py runserver 0.0.0.0:80
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数据库中增加的环境数据：

Web服务器接收到的来自ESP8266的HttpPost请求：

前端的get_environments请求：

3. 实验效果展示

通过前端地址访问：http://116.198.42.221/IOT/get_environments/
前端展示效果：

ESP8266 + DHT11 + OLED 展示效果：

整体效果图：

视频展示：