Mini Project Part 1: Temperature Monitor — Hardware Setup

Relax. We'll talk through this in plain words — no textbook voice.

What you'll walk away with

Get comfortable with Mini Project Part 1: Temperature Monitor — Hardware Setup, no intimidation required
Be able to wire the hardware and run the code yourself
Apply this concept right away in a real project

Let's think about this for a second

A DHT22 (or DHT11) temperature/humidity sensor connects via one GPIO pin (the data pin), plus power (3.3V) and ground — the wiring is simpler than I2C/SPI sensors since it communicates over a single data pin. This project brings together the concepts from earlier chapters (GPIO wiring, Python control, Linux commands) into one cohesive project.

Let's connect this to a real-world scenario

Connect the DHT22 sensor's 3 pins — VCC (3.3V), Data (a GPIO pin, e.g. BCM 4), and GND — to the Pi using a breadboard and jumper wires (following the same pattern as the LED wiring lesson earlier). Install the Adafruit_DHT or adafruit-circuitpython-dht Python library with pip install (same pattern as the earlier pip lesson).

Connect the DHT22 sensor's 3 pins (VCC, Data, GND) to the Pi
Install the adafruit-circuitpython-dht library with pip install
Double-check the wiring before powering on (make sure VCC/GND aren't reversed)

Let's walk through it together

bash

# Wiring (DHT22 to Pi)
# DHT22 VCC  → Pi 3.3V
# DHT22 Data → Pi GPIO 4 (BCM)
# DHT22 GND  → Pi GND

# Install library
pip install adafruit-circuitpython-dht
sudo apt install libgpiod2

You should see

Once the library is installed, you'll be all set to read sensor data with a Python script in Part 2.

5-Minute Try-It

If you have a DHT22 sensor, wire it up yourself following the wiring diagram, and run the library install command.

A quick word of caution

Changing the sensor wiring while the power is on can fry the sensor or even the Pi board — follow the same warning from the LED wiring lesson earlier: power off before you touch the wiring.

Easy traps

Frying the sensor by reversing the VCC/GND pins (remember the polarity concept from the LED lesson earlier in this tutorial)
Hitting an import error because you installed only the Python library without installing libgpiod2 (a system dependency) first

Now try it yourself

If you have a DHT22 sensor, wire it up yourself following the wiring diagram, and run the library install command.

You'll know it worked when: Once the library is installed, you'll be all set to read sensor data with a Python script in Part 2.