在這個項(xiàng)目中，我們將使用ESP32創(chuàng)建一個氣象站。基本原理是通過讀取DHT22和BMP180傳感器的數(shù)據(jù)，然后使用ESP32傳輸創(chuàng)建的網(wǎng)頁上，在網(wǎng)頁上顯示氣象數(shù)據(jù)。

電路圖

首先，將DHT22和ESP32連接起來。DHT22與ESP32的連接如下:

DHT22 引腳1 VCC —–>ESP32 / 3.3V;

DHT22 引腳2 DATA—–>ESP32 / D15;

DHT22引腳4 GND —–>ESP32 /GND.

然后將BMP180壓力傳感器連接到ESP32上。連接如下:

BMP180 Vin —–> ESP32 / 3.3V;

BMP180 GND —–> ESP32 /GND;

BMP180SCL —–> ESP32 / pin 22;(ESP32的22號引腳是SCL.)

BMP180SDA —–> ESP32 / pin 21;(ESP32的21號引腳是SDA.)

ESP32的22和21號引腳是I2C通信接口。詳見下圖ESP32的引腳圖

氣象站C代碼

#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

}

}

}

}

}

氣象站項(xiàng)目代碼釋義

首先，確保項(xiàng)目所需的所有庫均 include 了，然后定義連接DHT22溫度和濕度傳感器的引腳，再創(chuàng)建實(shí)例：

#include

#include

#include

#include

#define DHTPIN 15

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

Adafruit_BMP085 bmp;

接著存儲Wi-Fi名稱和密碼，同時定義并創(chuàng)建服務(wù)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函數(shù)中，會使用上面的Wi-Fi信數(shù)據(jù)將ESP32連接到的Wi-Fi網(wǎng)絡(luò)。如果連接到網(wǎng)絡(luò)成功，那么“connection successful”將顯示在串口監(jiān)視器上。否則，程序?qū)⒗^續(xù)嘗試，直到連接到Wi-Fi網(wǎng)絡(luò)。

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");

下面的命令會將IP地址顯示在串口監(jiān)視器上。

Serial.println（WiFi.localIP（））;

然后程序?qū)臃?wù)器，以便程序能夠接收和發(fā)送數(shù)據(jù)到瀏覽器上。

server.begin（）;

在loop函數(shù)中，程序能夠從傳感器讀取數(shù)據(jù)并存儲在變量中，這樣就可以在網(wǎng)頁上顯示數(shù)據(jù)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);

然后檢查客戶端是否有發(fā)送HTTP請求，如果有客戶端請求可用，那么程序?qū)⒋鎯Σ@示結(jié)果在串行監(jiān)視器上。在請求結(jié)束時，程序?qū)l(fā)送HTML命令，在網(wǎng)頁上顯示傳感器的數(shù)據(jù)。

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);

氣象站如何使用

首先，將代碼中的Wi-Fi名稱和密碼信息替換為你自己的。然后上傳代碼并打開串口監(jiān)視器。串口監(jiān)視器將顯示如下圖所示的IP地址。

在瀏覽器中輸入這個IP地址。輸入IP地址后，網(wǎng)頁會顯示如下圖所示。

現(xiàn)在傳感器數(shù)據(jù)就從氣象站上傳到網(wǎng)頁上了。