Uno R4 WiFi的AP_SimpleWebServer示例连接超时问题求助

问题描述 #

我是Arduino新手，刚入手Uno R4 WiFi做项目练习。尝试用官方的"AP_SimpleWebServer"示例实现Web控制LED，但访问串口输出的IP链接时总是连接超时。仅修改了arduino_secrets.h中的SSID和密码，其他代码未改动。串口监视器偶尔提示Please upgrade the firmware，不确定是否影响。已参考相关论坛帖子修改过AP名称，但问题依旧。

使用的代码 #

/*
  WiFi Web Server LED Blink

  A simple web server that lets you blink an LED via the web.
  This sketch will create a new access point (with no password).
  It will then launch a new server and print out the IP address
  to the Serial Monitor. From there, you can open that address in a web browser
  to turn on and off the LED on pin 13.

  If the IP address of your board is yourAddress:
    http://yourAddress/H turns the LED on
    http://yourAddress/L turns it off

  created 25 Nov 2012
  by Tom Igoe
  adapted to WiFi AP by Adafruit

  Find the full UNO R4 WiFi Network documentation here:
  https://docs.arduino.cc/tutorials/uno-r4-wifi/wifi-examples#access-point
 */

#include "WiFiS3.h"

#include "arduino_secrets.h" 

///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = SECRET_SSID;        // your network SSID (name)
char pass[] = SECRET_PASS;        // your network password (use for WPA, or use as key for WEP)
int keyIndex = 0;                 // your network key index number (needed only for WEP)

int led =  LED_BUILTIN;
int status = WL_IDLE_STATUS;
WiFiServer server(80);

void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }
  Serial.println("Access Point Web Server");

  pinMode(led, OUTPUT);      // set the LED pin mode

  // check for the WiFi module:
  if (WiFi.status() == WL_NO_MODULE) {
    Serial.println("Communication with WiFi module failed!");
    // don't continue
    while (true);
  }

  String fv = WiFi.firmwareVersion();
  if (fv < WIFI_FIRMWARE_LATEST_VERSION) {
    Serial.println("Please upgrade the firmware");
  }

  // by default the local IP address will be 192.168.4.1
  // you can override it with the following:
  WiFi.config(IPAddress(192,48,56,2));

  // print the network name (SSID);
  Serial.print("Creating access point named: ");
  Serial.println("Arduino");

  // Create open network. Change this line if you want to create an WEP network:
  status = WiFi.beginAP("Arduino", pass);
  if (status != WL_AP_LISTENING) {
    Serial.println("Creating access point failed");
    // don't continue
    while (true);
  }

  // wait 10 seconds for connection:
  delay(10000);

  // start the web server on port 80
  server.begin();

  // you're connected now, so print out the status
  printWiFiStatus();
}


void loop() {
  
  // compare the previous status to the current status
  if (status != WiFi.status()) {
    // it has changed update the variable
    status = WiFi.status();

    if (status == WL_AP_CONNECTED) {
      // a device has connected to the AP
      Serial.println("Device connected to AP");
    } else {
      // a device has disconnected from the AP, and we are back in listening mode
      Serial.println("Device disconnected from AP");
    }
  }
  
  WiFiClient client = server.available();   // listen for incoming clients

  if (client) {                             // if you get a client,
    Serial.println("new client");           // print a message out the serial port
    String currentLine = "";                // make a String to hold incoming data from the client
    while (client.connected()) {            // loop while the client's connected
      delayMicroseconds(10);                // This is required for the Arduino Nano RP2040 Connect - otherwise it will loop so fast that SPI will never be served.
      if (client.available()) {             // if there's bytes to read from the client,
        char c = client.read();             // read a byte, then
        Serial.write(c);                    // print it out to the serial monitor
        if (c == '\n') {                    // if the byte is a newline character

          // if the current line is blank, you got two newline characters in a row.
          // that's the end of the client HTTP request, so send a response:
          if (currentLine.length() == 0) {
            // HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
            // and a content-type so the client knows what's coming, then a blank line:
            client.println("HTTP/1.1 200 OK");
            client.println("Content-type:text/html");
            client.println();

            // the content of the HTTP response follows the header:
            client.print("<p style=\"font-size:7vw;\">Click <a href=\"/H\">here</a> turn the LED on<br></p>");
            client.print("<p style=\"font-size:7vw;\">Click <a href=\"/L\">here</a> turn the LED off<br></p>");

            // The HTTP response ends with another blank line:
            client.println();
            // break out of the while loop:
            break;
          }
          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
        }

        // Check to see if the client request was "GET /H" or "GET /L":
        if (currentLine.endsWith("GET /H")) {
          digitalWrite(led, HIGH);               // GET /H turns the LED on
        }
        if (currentLine.endsWith("GET /L")) {
          digitalWrite(led, LOW);                // GET /L turns the LED off
        }
      }
    }
    // close the connection:
    client.stop();
    Serial.println("client disconnected");
  }
}

void printWiFiStatus() {
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");
  Serial.println(WiFi.SSID());

  // print your WiFi shield's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("IP Address: ");
  Serial.println(ip);

  // print where to go in a browser:
  Serial.print("To see this page in action, open a browser to http://");
  Serial.println(ip);

}

解决建议 #

• 优先升级WiFi模块固件：串口提示的固件升级非常关键，旧版本固件可能存在AP模式的兼容性问题。打开Arduino IDE，依次点击工具->WiFi101 / WiFiNINA Firmware Updater，按照向导完成固件升级，确保版本为最新。
• 修正AP配置的关键错误：
  1. 代码中创建AP的名称是硬编码的"Arduino"，而非你在arduino_secrets.h中填写的SECRET_SSID，连接时要找名称为Arduino的WiFi网络，不是你的家庭WiFi。
  2. 注释掉WiFi.config(IPAddress(192,48,56,2))这行代码，使用默认的AP IP（192.168.4.1），避免自定义IP和设备网络冲突。
  3. 代码中WiFi.beginAP("Arduino", pass)创建的是带密码的AP，连接时输入的密码必须和SECRET_PASS一致，否则无法建立连接。
• 验证设备连接状态：打开串口监视器，观察是否出现Device connected to AP提示，若未出现，说明你的手机/电脑未成功连接到Arduino的AP，先排查WiFi连接问题。
• 调整Web访问方式：
  1. 连接Arduino的AP后，关闭手机的移动数据，避免网络自动切换。
  2. 直接在浏览器输入串口输出的IP（如http://192.168.4.1），先确认能否打开页面，再测试LED控制链接。
• 修复代码逻辑漏洞：原代码中判断HTTP请求的位置错误，可能导致无法触发LED控制。将判断GET /H和GET /L的代码移到换行处理的分支中，修改后的代码片段如下：

if (c == '\n') {
  if (currentLine.length() == 0) {
    // 发送HTTP响应的代码保持不变
    client.println("HTTP/1.1 200 OK");
    client.println("Content-type:text/html");
    client.println();

    client.print("<p style=\"font-size:7vw;\">Click <a href=\"/H\">here</a> turn the LED on<br></p>");
    client.print("<p style=\"font-size:7vw;\">Click <a href=\"/L\">here</a> turn the LED off<br></p>");

    client.println();
    break;
  } else {
    // 在这里处理请求判断
    if (currentLine.endsWith("GET /H")) {
      digitalWrite(led, HIGH);
    }
    if (currentLine.endsWith("GET /L")) {
      digitalWrite(led, LOW);
    }
    currentLine = "";
  }
}

内容的提问来源于stack exchange，提问作者Rob S