[Day11] Esp32s用AP mode + LED

13th鐵人賽自我挑戰 esp32s arduino

ks_wwlin

2021-09-12 18:51:31

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1.前言

講了那麼多天的理論，現在該來讓各位多動手實作啦，今天主要是會運用Esp32s內建的WiFi來進行實作，並融合兩個LED燈，達到可用手機連結Esp32s就可遠端操控LED的亮與滅。

2.Esp32s的WiFi運作模式

Esp32s的WiFi有三種運作模式，分別是AP、STA及AP/STA

AP mode
手機連接Esp32s (Esp32s當基地台)

STA mode
Esp32s去連接AP (手機或WiFi分享器當基地台)

而我這樣文字敘述肯定很多人到現在還是搞不清楚，所以我準備了一張圖片

圖片取自：使用者繪製

2-1.那麼這兩種區別有什麼呢?

其實我覺得最大的區別就是當Esp32s開啟STA mode時，可以去連接手機或AP基地台，而這時候Esp32s也就具備網路，可以上網抓數值，例如抓取PM2.5的數值，並用網頁或LCD去做顯示，可以做出更多不同的應用。

那接下來就直接進入主題吧，上次的實作呼吸燈還記得吧，不記得罰你回去複習『Day6 呼吸燈製作』，那上次只是讓LED燈自己跑程式，跑出呼吸燈的效果，但是今天就比較不同，是自己手動控制LED燈的亮滅狀態，那就直接看接線圖吧。

2-2.接線圖

圖片取自：使用者拍攝

許多人應該會想著，為什麼LED不用接地跟為什麼黃色那條要往下接到下方GND，那是因為A區的LED已經在板中已經牽線至下方GND區塊，所以A區LED要接地只需要把開發板的GND接線至下方GND區即可接地，對了還有LED有4顆，隨便挑兩顆就好。

3.程式碼

請修改第四行(ssidAP)及第五行(passwordAP)後方的"xxxx"，請將資訊輸入至""中，千萬不可把""刪除，xxxx可刪除，修改完畢後就可進行燒入，如果忘記如何燒入可以回顧『Day4 Arduino測試燒錄』。

#include <WiFi.h>

// Replace with your network credentials
const char* ssidAP     = "xxxx"; //Esp32s基地台名稱(隨便都可以，要英文且盡量不要跟附近的WiFi撞名)
const char* passwordAP = "xxxxxxxx";//Esp32s基地台密碼(至少要8碼，例如12345678)

// Set web server port number to 80
WiFiServer server(80);

// Variable to store the HTTP request
String header;

// Auxiliar variables to store the current output state
String output0State = "off";
String output2State = "off";

// Assign output variables to GPIO pins
const int output0 = 23;
const int output2 = 22;

void setup() {
  Serial.begin(115200);
  // Initialize the output variables as outputs
  pinMode(output0, OUTPUT);
  pinMode(output2, OUTPUT);
  // Set outputs to LOW
  digitalWrite(output0, LOW);
  digitalWrite(output2, LOW);

  // Connect to Wi-Fi network with SSID and password
  Serial.print("Setting AP (Access Point)…");
  // Remove the password parameter, if you want the AP (Access Point) to be open
  WiFi.softAP(ssidAP, passwordAP);
  delay(500);
  IPAddress IP = WiFi.softAPIP();
  Serial.print("AP IP address: ");
  Serial.println(IP);
  
  server.begin();
}

void loop(){
  WiFiClient client = server.available();   // Listen for incoming clients

  if (client) {                             // If a new client connects,
    Serial.println("New Client.");          // print a message out in 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
        header += c;
        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("Connection: close");
            client.println();
            
            // turns the GPIOs on and off
            if (header.indexOf("GET /23/on") >= 0) {
              Serial.println("GPIO 23 on");
              output0State = "on";
              digitalWrite(output0, HIGH);
            } else if (header.indexOf("GET /23/off") >= 0) {
              Serial.println("GPIO 23 off");
              output0State = "off";
              digitalWrite(output0, LOW);
            } else if (header.indexOf("GET /22/on") >= 0) {
              Serial.println("GPIO 22 on");
              output2State = "on";
              digitalWrite(output2, HIGH);
            } else if (header.indexOf("GET /22/off") >= 0) {
              Serial.println("GPIO 22 off");
              output2State = "off";
              digitalWrite(output2, LOW);
            }
            
            // Display the HTML web page
            client.println("<!DOCTYPE html><html>");
            client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
            client.println("<link rel=\"icon\" href=\"data:,\">");
            // CSS to style the on/off buttons 
            // Feel free to change the background-color and font-size attributes to fit your preferences
            client.println("<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}");
            client.println(".button { background-color: #4CAF50; border: none; color: white; padding: 16px 40px;");
            client.println("text-decoration: none; font-size: 30px; margin: 2px; cursor: pointer;}");
            client.println(".button2 {background-color: #555555;}</style></head>");
            
            // Web Page Heading
            client.println("<body><h1>ESP32 Web Server</h1>");
            
            // Display current state, and ON/OFF buttons for GPIO 23  
            client.println("<p>GPIO 23 - State " + output0State + "</p>");
            // If the output0State is off, it displays the ON button       
            if (output0State=="off") {
              client.println("<p><a href=\"/23/on\"><button class=\"button\">ON</button></a></p>");
            } else {
              client.println("<p><a href=\"/23/off\"><button class=\"button button2\">OFF</button></a></p>");
            } 
               
            // Display current state, and ON/OFF buttons for GPIO 22  
            client.println("<p>GPIO 22 - State " + output2State + "</p>");
            // If the output2State is off, it displays the ON button       
            if (output2State=="off") {
              client.println("<p><a href=\"/22/on\"><button class=\"button\">ON</button></a></p>");
            } else {
              client.println("<p><a href=\"/22/off\"><button class=\"button button2\">OFF</button></a></p>");
            }
            client.println("</body></html>");
            
            // 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
        }
      }
    }
    // Clear the header variable
    header = "";
    // Close the connection
    client.stop();
    Serial.println("Client disconnected.");
    Serial.println("");
  }
}