单片机课堂思考题-如何用手机控制单片机IO口-如点亮一个LED

Posted 2021-12-05 zhangrelay

主要考察学生思路，常见现象是直接网上查找然后开始刷刷看并写到本子上。

很难了，思考-检索-推荐，在互联网算法的投喂下，大部分已经丧失了独立思考的能力了。

第一步，需要使手机和单片机建立连接，通常手机不用串口连接外设，一般而言适用无线wifi和蓝牙。

第二步，才是构思程序架构，比如控制哪些IO口，如何配置wifi和蓝牙等。

第三步，在设计好程序流程图之后，依据具体芯片特色进行程序设计。

简言之，连通性和控制程序。

参考程序如下：

IO口可以更换为2、4等，依据具体情况适当调整。

#include <WiFi.h>

const char* ssid     = "yourssid";
const char* password = "yourpasswd";

WiFiServer server(80);

void setup()
{
    Serial.begin(115200);
    pinMode(5, OUTPUT);      // set the LED pin mode

    delay(10);

    // We start by connecting to a WiFi network

    Serial.println();
    Serial.println();
    Serial.print("Connecting to ");
    Serial.println(ssid);

    WiFi.begin(ssid, password);

    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }

    Serial.println("");
    Serial.println("WiFi connected.");
    Serial.println("IP address: ");
    Serial.println(WiFi.localIP());
    
    server.begin();

}

int value = 0;

void loop(){
 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
      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 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("Click <a href=\\"/H\\">here</a> to turn the LED on pin 5 on.<br>");
            client.print("Click <a href=\\"/L\\">here</a> to turn the LED on pin 5 off.<br>");

            // 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(5, HIGH);               // GET /H turns the LED on
        }
        if (currentLine.endsWith("GET /L")) {
          digitalWrite(5, LOW);                // GET /L turns the LED off
        }
      }
    }
    // close the connection:
    client.stop();
    Serial.println("Client Disconnected.");
  }
}

连接上WiFi之后，一定要注意查看串口获取单片机wifi的ip地址然后，适用手机或者电脑的浏览器登陆，就可以控制灯亮灭了。

也就是控制IO口输出高低电平。