如何使用ESP32创建一个气象站

　　在这个项目中，我们将使用ESP32创建一个气象站。基本原理是通过读取DHT22和BMP180传感器的数据，然后使用ESP32传输创建的网页上，在网页上显示气象数据。

　　电路图

　　首先，将DHT22和ESP32连接起来。DHT22与ESP32的连接如下:

DHT22 引脚1  VCC   —–>ESP32 / 3.3V;

DHT22 引脚2 DATA—–>ESP32 / D15;

DHT22 引脚4 GND —–>ESP32 /GND.

然后将BMP180压力传感器连接到ESP32上。连接如下:

BMP180 Vin     —–> ESP32 / 3.3V;

BMP180 GND  —–> ESP32 /GND;

BMP180 SCL  —–> ESP32 / pin 22;(ESP32的22号引脚是SCL.)

BMP180 SDA —–> ESP32 / pin 21;(ESP32的21号引脚是SDA.)

ESP32的22和21号引脚是I2C通信接口。详见下图ESP32的引脚图

　　气象站C代码

　　#include

#include

#include

#include

#define DHTPIN 15

#define DHTTYPE DHT22

DHT dht(DHTPIN, DHTTYPE);

Adafruit_BMP085 bmp;

char pressure_value[4];

const char* wifi_name = "Asus_2.4G"; //Your Wifi name

const char* wifi_pass = "basemu.com"; //Your Wifi password

WiFiServer server(80); //Port 80

void setup()

{

Serial.begin(115200);

dht.begin();

bmp.begin();

// Let's connect to wifi network

Serial.print("Connecting to ");

Serial.print(wifi_name);

WiFi.begin(wifi_name, wifi_pass); //Connecting to wifi network

while (WiFi.status() != WL_CONNECTED) //Waiting for the responce of wifi network

{

delay(500);

Serial.print(".");

}

Serial.println("");

Serial.println("Connection Successful");

Serial.print("IP address: ");

Serial.println(WiFi.localIP()); //Getting the IP address at which our webserver will be created

Serial.println("Type the above IP address into a browser search bar");

server.begin(); //Starting the server

}

void loop()

{

String pressure = String(bmp.readPressure());

// convert the reading to a char array

pressure.toCharArray(pressure_value, 4);

float hum = dht.readHumidity();

float temp = dht.readTemperature();

float fah = dht.readTemperature(true);

float heat_index = dht.computeHeatIndex(fah, hum);

float heat_indexC = dht.convertFtoC(heat_index);

WiFiClient client = server.available(); //Checking for incoming clients

if (client)

{

Serial.println("new client");

String currentLine = ""; //Storing the incoming data in the string

while (client.connected())

{

if (client.available()) //if there is some client data available

{

char c = client.read(); // read a byte

if (c == '\n') // check for newline character,

{

if (currentLine.length() == 0) //if line is blank it means its the end of the client HTTP request

{

client.print("

");

client.print("

);

client.print("

);

client.print(temp);

client.print("
Temperature in fah: ");

client.print(fah);

client.print("
Humidity is: ");

client.print(hum);

client.print("
Heat Index in C: ");

client.print(heat_indexC);

client.print("
Heat Index in fah: ");

client.print(heat_index);

client.print("
Pressure is: ");

client.print(pressure_value);

client.print("hpa");

client.print("

");

break; // break out of the while loop:

}

else

{ // if you got a newline, then clear currentLine:

currentLine = "";

}

}

else if (c != '\r')

{ // if you got anything else but a carriage return character,

currentLine += c; // add it to the end of the currentLine

}

}

}

}

}

　　气象站项目代码释义

　　首先，确保项目所需的所有库均 include 了，然后定义连接DHT22温度和湿度传感器的引脚，再创建实例：

　　#include

#include

#include

#include

#define DHTPIN 15

#define DHTTYPE DHT22 DHT dht(DHTPIN, DHTTYPE);

Adafruit_BMP085 bmp;

　　接着存储Wi-Fi名称和密码，同时定义并创建服务器的端口。

　　const char* wifi_name = "Asus_2.4G"; //Your Wifi name const char*

wifi_pass = "basemu.com"; //Your Wifi password

WiFiServer server(80); //Port 80

　　在setup函数中，会使用上面的Wi-Fi信数据将ESP32连接到的Wi-Fi网络。如果连接到网络成功，那么“connection successful”将显示在串口监视器上。否则，程序将继续尝试，直到连接到Wi-Fi网络。

　Serial.print("Connecting to ");

Serial.print(wifi_name);

WiFi.begin(wifi_name, wifi_pass); //Connecting to wifi network

while (WiFi.status() != WL_CONNECTED) { //Waiting for the response of wifi network

delay(500);

Serial.print(".");

}

Serial.println("");

Serial.println("Connection Successful");

　　下面的命令会将IP地址显示在串口监视器上。

　　Serial.println（WiFi.localIP（））;

　　然后程序将启动服务器，以便程序能够接收和发送数据到浏览器上。

　　server.begin（）;

　　在loop函数中，程序能够从传感器读取数据并存储在变量中，这样就可以在网页上显示数据了。

　　String pressure = String(bmp.readPressure());

pressure.toCharArray(pressure_value, 4);

float hum = dht.readHumidity();

float temp = dht.readTemperature();

float fah = dht.readTemperature(true);

float heat_index = dht.computeHeatIndex(fah, hum);

float heat_indexC = dht.convertFtoC(heat_index);

　　然后检查客户端是否有发送HTTP请求，如果有客户端请求可用，那么程序将存储并显示结果在串行监视器上。在请求结束时，程序将发送HTML命令，在网页上显示传感器的数据。

　　WiFiClient client = server.available(); //Checking for incoming clients

if (client){

Serial.println("new client");

String currentLine = ""; //Storing the incoming data in the string

while (client.connected()){

if (client.available()) //if there is some client data available

{

char c = client.read(); // read a byte

if (c == '\n') // check for newline character,

{

if (currentLine.length() == 0) //if line is blank it means it’s the end of the client HTTP

request { client.print("");

client.print("

ESP32 Weather Station

");

client.print("Temperature in C: ");

client.print(temp);

client.print(" Temperature in fah: ");

client.print(fah);

client.print(" Humidity is: ");

client.print(hum);

　　气象站如何使用

　　首先，将代码中的Wi-Fi名称和密码信息替换为你自己的。然后上传代码并打开串口监视器。串口监视器将显示如下图所示的IP地址。

　　在浏览器中输入这个IP地址。输入IP地址后，网页会显示如下图所示。

　　现在传感器数据就从气象站上传到网页上了。