Situatie

The DHT11 and DHT22 measure temperature and humidity. DHT22 offers higher accuracy and a wider range.

Pin	Description
VCC	+5V
DATA	Data output (connect to D2)
NC	Not connected
GND	Ground

BMP180 / BME280

Measures pressure and temperature using the I2C interface.

Pin	Description
VIN	+3.3V or +5V
GND	Ground
SCL	I2C Clock (A5)
SDA	I2C Data (A4)

LCD (16×2 I2C)

Displays data using the I2C interface — only two wires are required (SDA, SCL).
The most common I2C addresses are 0x27 or 0x3F.

Wiring Diagram

Component	Arduino Pin	Notes
DHT11 Data	D2	Use 10kΩ pull-up resistor (optional)
BMP180 SDA	A4	I2C Data
BMP180 SCL	A5	I2C Clock
LCD SDA	A4	Shared with BMP180
LCD SCL	A5	Shared with BMP180
Power (+)	5V	Common power line
Ground (–)	GND	Common ground

On Arduino Mega, use SDA = 20 and SCL = 21 instead.

Arduino Code Example

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BMP085.h>
#include <DHT.h>
#include <LiquidCrystal_I2C.h>

// Define sensors
#define DHTPIN 2
#define DHTTYPE DHT11   // or DHT22

DHT dht(DHTPIN, DHTTYPE);
Adafruit_BMP085 bmp;
LiquidCrystal_I2C lcd(0x27, 16, 2); // Change address if needed (0x3F or 0x27)

void setup() {
  Serial.begin(9600);
  lcd.begin(16, 2);
  lcd.backlight();
  dht.begin();

  if (!bmp.begin()) {
    Serial.println("BMP180 not found!");
    lcd.print("BMP Error!");
    while (1);
  }

  lcd.clear();
  lcd.print("Weather Station");
  delay(2000);
}

void loop() {
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  float p = bmp.readPressure() / 100.0; // hPa

  if (isnan(h) || isnan(t)) {
    Serial.println("DHT read error!");
    return;
  }

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("T:");
  lcd.print(t);
  lcd.print((char)223);
  lcd.print("C H:");
  lcd.print(h);
  lcd.print("%");

  lcd.setCursor(0, 1);
  lcd.print("P:");
  lcd.print(p);
  lcd.print(" hPa");

  Serial.print("Temp: "); Serial.print(t);
  Serial.print(" °C  Hum: "); Serial.print(h);
  Serial.print("%  Pressure: "); Serial.print(p);
  Serial.println(" hPa");

  delay(2000);
}

Explanation: This program reads data from the DHT and BMP sensors, then prints it to both the Serial Monitor and the LCD screen.

How It Works

1. The sensors measure temperature, humidity, and pressure.
2. Arduino reads and formats this data.
3. The LCD displays readings in real time.
4. Every few seconds, the data updates automatically.

Troubleshooting

Problem	Possible Cause	Solution
LCD shows random text	Wrong I2C address	Try 0x3F instead of 0x27
“BMP180 not found!”	Wiring issue	Check SDA/SCL and power
DHT readings show NaN	Missing library or bad sensor	Install DHT library, recheck wiring
LCD blank	Contrast too low or backlight off	Adjust contrast screw or enable backlight

Install these from Arduino IDE → Sketch → Include Library → Manage Libraries:

• DHT sensor library by Adafruit
• Adafruit Unified Sensor
• Adafruit BMP085 Library or Adafruit BME280
• LiquidCrystal_I2C

Optional: IoT Integration

Add an ESP8266 or ESP32 to send data to cloud platforms such as:

• ThingSpeak
• Blynk
• Adafruit IO

Use libraries like ESP8266WiFi.h and HTTPClient.h to upload readings as HTTP requests.

Expansion Ideas

• Add a rain sensor or anemometer (wind speed)
• Store data on an SD card
• Add a real-time clock (RTC) for timestamped data
• Display graphs on a web dashboard.

Solutie

Tip solutie

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