ESP32 Web Server: Room Monitoring and Controlling System

18220021 Divya Maharani Lazuardi

5 min readApr 6, 2022

Pada project kali ini, akan ditunjukkan pemanfaatan ESP32 untuk memantau dan mengontrol sebuah ruangan dengan menggunakan web server.

Hardware Components:

ESP32 development board
USB Cable
Breadboard
Jumper cable
LED lights (5mm)
330 ohm resistor
Smartphone
BMP280 Sensor

Software:

Arduino IDE

Langkah Pengerjaan

Persiapkan komponen yang dibutuhkan dan lakukan instalasi rangkaian seperti gambar di bawah ini.

2. Sambungkan ESP32 Anda dengan laptop dengan menggunakan USB cable.

3. Pastikan Adafruit BMP280 Libarary sudah terinsatll pada Arduino IDE Anda. Jika belum, ada dapat meng-instal library tersebut melalui Tools > manage Library. Lalu pada kolom pencarian, masukkan nama “Adafruit BMP280” dan klik tombol install.

4. Setelah Library sudah terpastikan terinstal, copy-paste code berikut dan compile.

#include <Wire.h>
#include <WiFi.h>
#include <SPI.h>
#include <Adafruit_BMP280.h>
#define BMP_SCK  (13)
#define BMP_MISO (12)
#define BMP_MOSI (11)
#define BMP_CS   (10)Adafruit_BMP280 bmp; // I2C//Adafruit_BMP280 bmp(BMP_CS); // hardware SPI
//Adafruit_BMP280 bmp(BMP_CS, BMP_MOSI, BMP_MISO,  BMP_SCK);// Replace // Replace with your network credentials
const char* ssid     = "REPLACE_WITH_YOUR_SSID";
const char* password = "REPLACE_WITH_YOUR_PASSWORD";// 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 outputState = "off";// Assign output variables to GPIO pins
const int output = 23;// Current time
unsigned long currentTime = millis();// Previous time
unsigned long previousTime = 0; // Define timeout time in milliseconds (example: 2000ms = 2s)
const long timeoutTime = 2000;
void setup() {
  Serial.begin(115200);
  while ( !Serial ) delay(100);   // wait for native usb
  Serial.println(F("BMP280 test"));
  unsigned status;
  //status = bmp.begin(BMP280_ADDRESS_ALT, BMP280_CHIPID);
  status = bmp.begin(0x76);
  if (!status) {
    Serial.println(F("Could not find a valid BMP280 sensor, check wiring or "
                      "try a different address!"));
    Serial.print("SensorID was: 0x"); Serial.println(bmp.sensorID(),16);
    Serial.print("        ID of 0xFF probably means a bad address, a BMP 180 or BMP 085\n");
    Serial.print("   ID of 0x56-0x58 represents a BMP 280,\n");
    Serial.print("        ID of 0x60 represents a BME 280.\n");
    Serial.print("        ID of 0x61 represents a BME 680.\n");
    while (1) delay(10);
  }
/* Default settings from datasheet. */
  bmp.setSampling(Adafruit_BMP280::MODE_NORMAL,     /* Operating Mode. */
                  Adafruit_BMP280::SAMPLING_X2,     /* Temp. oversampling */
                  Adafruit_BMP280::SAMPLING_X16,    /* Pressure oversampling */
                  Adafruit_BMP280::FILTER_X16,      /* Filtering. */
                  Adafruit_BMP280::STANDBY_MS_500); /* Standby time. */
  
// Initialize the output variables as outputs
  pinMode(output, OUTPUT);
  // Set outputs to LOW
  digitalWrite(output, LOW);
   
// Connect to Wi-Fi network with SSID and password
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  
// Print local IP address and start web server
  Serial.println("");
  Serial.println("WiFi connected.");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  server.begin();
}
void loop() {
   WiFiClient client = server.available();   // Listen for incoming clients
if (client) {                             // If a new client connects,
    currentTime = millis();
    previousTime = currentTime;
    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() && currentTime - previousTime <= timeoutTime) {  // loop while the client's connected
      currentTime = millis();
      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("LED on");
              outputState = "on";
              digitalWrite(output, HIGH);
            } else if (header.indexOf("GET /23/off") >= 0) {
              Serial.println("LED off");
              outputState = "off";
              digitalWrite(output, 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 table 
            client.println("<style>body { text-align: center; font-family: \"Trebuchet MS\", Arial;}");
            client.println("table { border-collapse: collapse; width:35%; margin-left:auto; margin-right:auto; }");
            client.println("th { padding: 12px; background-color: #0043af; color: white; }");
            client.println("tr { border: 1px solid #ddd; padding: 12px; }");
            client.println("tr:hover { background-color: #bcbcbc; }");
            client.println("td { border: none; padding: 12px; }");
            client.println(".sensor { color:#FF0000; font-weight: bold; padding: 1px; }");
            // CSS to style the on/off buttons 
            client.println("<style>html { font-family: Sans-serif; display: inline-block; margin: 0px auto; text-align: center;}");
            client.println(".button { background-color: #0043af; border: none; color: white; padding: 16px 40px;");
            client.println("text-decoration: none; font-size: 30px; margin: 2px; cursor: pointer;}");
            client.println(".button2 {background-color: #ff0000;}</style></head>");
                        
            // Web Page Heading
            client.println("</style></head><body><h1>Room Monitoring and Controlling System</h1>");
            client.println("<table><tr><th>MEASUREMENT</th><th>VALUE</th></tr>");
            client.println("<tr><td>Temperature on Celcius</td><td><span class=\"sensor\">");
            client.println(bmp.readTemperature());
            client.println(" *C</span></td></tr>");  
            client.println("<tr><td>Temperature on Fahrenheit</td><td><span class=\"sensor\">");
            client.println(1.8 * bmp.readTemperature() + 32);
            client.println(" *F</span></td></tr>");       
            client.println("<tr><td>Pressure</td><td><span class=\"sensor\">");
            client.println(bmp.readPressure() / 100.0F);
            client.println(" hPa</span></td></tr>");
            client.println("<tr><td>Approximate Altitude</td><td><span class=\"sensor\">");
            client.println(bmp.readAltitude(1013.25));
            client.println(" m</span></td></tr>"); 
            // Display current state, and ON/OFF buttons for GPIO 23
            client.println("<p>Fan State " + outputState + "</p>");       
            if (outputState=="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>");
            } 
            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("");
  }
}.