ESP32 使用 Wi-Fi
传输传感器数据可按以下步骤实现：
### 硬件连接
将传感器与
ESP32 正确连接，不同的传感器连接方式有所不同。例如，对于 I2C 接口的传感器，通常将传感器的 SDA 和 SCL 引脚分别连接到
ESP32 的相应 I2C 引脚；对于数字或模拟输出的传感器，连接到
ESP32 对应的 GPIO 引脚。
### 配置 Wi-Fi
在代码中配置
ESP32 连接到 Wi-Fi 网络。以下是一个简单的示例代码：
```cpp
#include <
WiFi.h>
const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";
void setup() {
Serial.begin(115200);
WiFi.begin(ssid, password);
while (
WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.println("Connecting to
WiFi...");
}
Serial.println("Connected to
WiFi");
}
void loop() {
// 主循环代码
}
```
### 读取传感器数据
根据传感器的类型，
使用相应的库来读取传感器数据。以 DHT11 温湿度传感器为例：
```cpp
#include <
WiFi.h>
#include "DHT.h"
#define DHTPIN 2 // DHT 传感器连接的引脚
#define DHTTYPE DHT11 // DHT 类型
DHT dht(DHTPIN, DHTTYPE);
const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";
void setup() {
Serial.begin(115200);
WiFi.begin(ssid, password);
while (
WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.println("Connecting to
WiFi...");
}
Serial.println("Connected to
WiFi");
dht.begin();
}
void loop() {
float temperature = dht.readTemperature();
float humidity = dht.readHumidity();
if (!isnan(temperature) && !isnan(humidity)) {
Serial.print("Temperature: ");
Serial.print(temperature);
Serial.print(" °C, Humidity: ");
Serial.print(humidity);
Serial.println(" %");
}
delay(2000);
}
```
### 数据
传输
读取到传感器数据后，可通过不同的网络协议将数据
传输到目标服务器或设备。常见的协议有 HTTP、MQTT 等。
#### HTTP 协议
使用 HTTP POST 请求将数据发送到服务器：
```cpp
#include <
WiFi.h>
#include <
WiFiClient.h>
#include <HTTPClient.h>
#include "DHT.h"
#define DHTPIN 2
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);
const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";
void setup() {
Serial.begin(115200);
WiFi.begin(ssid, password);
while (
WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.println("Connecting to
WiFi...");
}
Serial.println("Connected to
WiFi");
dht.begin();
}
void loop() {
float temperature = dht.readTemperature();
float humidity = dht.readHumidity();
if (!isnan(temperature) && !isnan(humidity)) {
if (
WiFi.status() == WL_CONNECTED) {
HTTPClient http;
http.begin("http://your_server_address");
String postData = "temperature=" + String(temperature) + "&humidity=" + String(humidity);
http.addHeader("Content-Type", "application/x-www-form-urlencoded");
int httpResponseCode = http.POST(postData);
if (httpResponseCode > 0) {
Serial.print("HTTP Response code: ");
Serial.println(httpResponseCode);
} else {
Serial.print("Error on sending POST: ");
Serial.println(httpResponseCode);
}
http.end();
}
}
delay(5000);
}
```
#### MQTT 协议
使用 MQTT 协议需要引入相应的库，如 PubSubClient：
```cpp
#include <
WiFi.h>
#include <PubSubClient.h>
#include "DHT.h"
#define DHTPIN 2
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);
const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";
const char* mqttServer = "your_mqtt_server";
const int mqttPort = 1883;
const char* mqttUser = "your_mqtt_user";
const char* mqttPassword = "your_mqtt_password";
WiFiClient espClient;
PubSubClient client(espClient);
void setup() {
Serial.begin(115200);
WiFi.begin(ssid, password);
while (
WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.println("Connecting to
WiFi...");
}
Serial.println("Connected to
WiFi");
dht.begin();
client.setServer(mqttServer, mqttPort);
}
void reconnect() {
while (!client.connected()) {
Serial.print("Attempting MQTT connection...");
if (client.connect("
ESP32Client", mqttUser, mqttPassword)) {
Serial.println("connected");
} else {
Serial.print("failed, rc=");
Serial.print(client.state());
Serial.println(" try again in 5 seconds");
delay(5000);
}
}
}
void loop() {
if (!client.connected()) {
reconnect();
}
float temperature = dht.readTemperature();
float humidity = dht.readHumidity();
if (!isnan(temperature) && !isnan(humidity)) {
String temperatureTopic = "sensor/temperature";
String humidityTopic = "sensor/humidity";
client.publish(temperatureTopic.c_str(), String(temperature).c_str());
client.publish(humidityTopic.c_str(), String(humidity).c_str());
}
client.loop();
delay(5000);
}
```
本文介绍了如何使用ESP32开发板配合摄像头模块，通过WiFi进行视频数据的传输。从准备工作、连接摄像头、设置WiFi、捕获传输视频到接收端的处理，详细阐述了实现过程，并提供了示例代码。
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