Build Instructions

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• 1

  Step 1: Circuit Diagram & Wiring

  Connect your components according to the table below:

  • DHT 11 Signal to Arduino Pin D2
  • DHT 11 GND to Arduino's GND Pin
  • DHT 11 VCC to Arduino's 3.3v Pin

  
  

  • OLED VCC to Arduino's 5v Pin
  • OLED GND to Arduino's GND Pin
  • OLED SCL to Arduino's SCL Pin
  • OLED SDA to Arduino's SDA Pin

  Tip: Ensure your OLED I2C address is set to 0x3c. You can use an I2C scanner sketch if unsure.

• 2

  Step 2: Installing Libraries

  To make your project run smoothly, open your Arduino IDE and install these libraries:

  1. Adafruit SSD1306
  2. Adafruit GFX Library
  3. DHT Sensor Library

  Install them via:

  Sketch -> Include Library -> Manage Libraries...

  Sketch -> Include Library -> Manage Libraries...

  Then search each one by name and click Install.

• 3

  Step 3: Upload the Code

  Now It's time to program your Arduino.

  here's the full, ready-to-upload code:

  #include <Wire.h>
  #include <Adafruit_GFX.h>
  #include <Adafruit_SSD1306.h>
  #include <DHT.h>
  
  // ==== OLED SETTINGS ====
  #define SCREEN_WIDTH 128
  #define SCREEN_HEIGHT 64
  #define OLED_ADDR 0x3C
  Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
  
  // ==== DHT SETTINGS ====
  #define DHTPIN 2
  #define DHTTYPE DHT11
  DHT dht(DHTPIN, DHTTYPE);
  
  void setup() {
    Serial.begin(115200);
    delay(1000);
    Serial.println("Initializing DHT11 + SSD1306 OLED...");
  
    if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
      Serial.println("❌ SSD1306 not found! Check wiring or I2C address.");
      while (1);
    }
  
    display.clearDisplay();
    display.setTextColor(SSD1306_WHITE);
    display.setTextSize(1);
    display.setCursor(20, 25);
    display.println("Initializing...");
    display.display();
  
    dht.begin();
    delay(2000);
  }
  
  void loop() {
    delay(2000);
  
    float humidity = dht.readHumidity();
    float temperature = dht.readTemperature();
  
    if (isnan(humidity) || isnan(temperature)) {
      Serial.println("⚠️ Failed to read from DHT11 sensor!");
      display.clearDisplay();
      display.setTextSize(1);
      display.setCursor(25, 25);
      display.println("Sensor Error!");
      display.display();
      return;
    }
  
    int tempInt = (int)temperature;
    int humInt  = (int)humidity;
  
    Serial.print("Temperature: ");
    Serial.print(tempInt);
    Serial.print(" °C | Humidity: ");
    Serial.print(humInt);
    Serial.println(" %");
  
    display.clearDisplay();
  
    display.setTextSize(1);
    display.setCursor(35, 0);
    display.println("DHT11 DATA");
  
    display.setTextSize(1);
    display.setCursor(0, 20);
    display.print("Temp: ");
    display.print(tempInt);
    display.println(" C");
  
    display.setCursor(0, 40);
    display.print("Hum : ");
    display.print(humInt);
    display.println(" %");
  
    display.display();
  }

  Once uploaded, open the Serial Monitor (115200 baud) to view live readings.

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