This project teaches you:
✔ How to use GPIO pins
✔ How to read a sensor
✔ How to write Python code
✔ How to display results on screen or terminal
✔ How Raspberry Pi interacts with the real world

📦 1. What You Need

Very simple and cheap components:

We will use the DHT22 (recommended) because it's more accurate.

🔌 2. Connect the Sensor to the Raspberry Pi

DHT22 Pinout

1. VCC → 3.3V pin on Raspberry Pi
2. DATA → GPIO 4 (Pin 7 on header)
3. GND → Ground pin

Here is the wiring:

💻 3. Install the Required Library

Open the Terminal on your Raspberry Pi and run:

sudo apt update
sudo apt install python3-pip
pip3 install Adafruit_DHT

This library allows Python to communicate with the sensor.

🧪 4. Python Code to Read Temperature & Humidity

Create a file:

nano dht22.py

Paste this code:

import Adafruit_DHT
import time

sensor = Adafruit_DHT.DHT22
gpio_pin = 4  # We are using GPIO 4

while True:
    humidity, temperature = Adafruit_DHT.read_retry(sensor, gpio_pin)

    if humidity is not None and temperature is not None:
        print(f"Temp: {temperature:.1f}°C   Humidity: {humidity:.1f}%")
    else:
        print("Failed to read sensor data. Trying again...")

    time.sleep(2)

Save and exit:
Press CTRL + X, then Y, then Enter

▶️ 5. Run Your Project

In the terminal:

python3 dht22.py

You will now see live readings like:

Temp: 24.8°C   Humidity: 43.6%
Temp: 24.9°C   Humidity: 43.5%
Temp: 25.0°C   Humidity: 43.4%

🎉 Congratulations! Your first Raspberry Pi hardware project works!

🌟 6. Optional Improvements (Highly Recommended)

✔ Display the values on a small LCD screen

Using a 16x2 LCD or OLED display.

✔ Create a dashboard accessible from your phone

Using Flask (Python) to make a mini web server showing temperature.

✔ Save the temperatures in a file or database

So you can draw graphs over time.

✔ Add an alert system

Send email or Telegram alerts if temperature > 30°C.

✔ Use it as a real IoT device

Send data to the cloud (Thingspeak, MQTT, Firebase…).