Arduino MicroPython DHT22 Temperature Humidity Sensor
This guide shows you how to use the DHT22 temperature and humidity sensor with Arduino and MicroPython. You will learn:
- How to connect the DHT22 sensor to an Arduino.
- How to connect the DHT22 module to an Arduino.
- How to write MicroPython code for Arduino to read temperature and humidity data from the DHT22 sensor and module.
Hardware Preparation
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables.
Additionally, some of these links are for products from our own brand, DIYables.
Overview of DHT22 Temperature and Humidity Sensor
| DHT22 | |
|---|---|
| Temperature Range | -40°C to 80°CW |
| Temperature Accuracy | ± 0.5°C |
| Humidity Range | 0% to 100% |
| Humidity Accuracy | ± 2 to 5% |
| Reading Rate | 0.5Hz (once every 2 seconds) |
| Operating Voltage | 3 to 5V |
Pinout
There are two types of DHT22: one is just the sensor, and the other is a complete module.
The DHT22 sensor has four pins:
- GND pin: Connect to GND (0 volts)
- VCC pin: Connect to VCC (5 volts or 3.3 volts)
- DATA pin: Used for communication between the sensor and Arduino
- NC pin: Not used, you can ignore it
The DHT22 module has three pins:
- GND pin: Connect to GND (0 volts)
- VCC pin: Connect to VCC (5 volts or 3.3 volts)
- DATA pin: Used for sending information between the sensor and Arduino
Some manufacturers provide the DHT22 sensor as a module with three pins labeled GND, VCC, and DATA (or sometimes -, +, and OUT).
Wiring Diagram
Arduino - DHT22 Sensor Wiring
Connect a resistor ranging from 5K to 10K Ohms between the DHT22 sensor and the Arduino to keep the data line high and enable communication. We need to use a breadboard
This image is created using Fritzing. Click to enlarge image
Arduino - DHT22 Module Wiring
Most DHT22 sensor modules include a built-in resistor, so you don't need to add another one. This makes the wiring or soldering process easier.
This image is created using Fritzing. Click to enlarge image
Arduino MicroPython Code - DHT22
"""
This Arduino MicroPython script was developed by newbiely.com
This Arduino MicroPython script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-micropython/arduino-micropython-dht22-temperature-humidity-sensor
"""
import machine
import time
import dht
DHT22_PIN = 'D2' # The Arduino Giga WiFi pin D2 connected to the DHT22 sensor
# Initialize the DHT22 sensor
DHT22 = dht.DHT22(machine.Pin(DHT22_PIN))
# Read data from the sensor every 2 seconds
while True:
try:
DHT22.measure()
temp = DHT22.temperature() # Gets the temperature in Celsius
humidity = DHT22.humidity() # Gets the relative humidity in %
print("Temperature: {:.2f}°C, Humidity: {:.2f}%".format(temp, humidity))
except OSError as e:
print("Failed to read from DHT22 sensor:", e)
time.sleep(2)
Detailed Instructions
Here’s instructions on how to run the above MicroPython code on Arduino with Thonny IDE:
- Make sure Thonny IDE is installed on your computer.
- Make sure MicroPython firmware is installed on your Arduino board.
- If you are new to Arduino with MicroPython, see the Getting Started with Arduino and MicroPython.
- Connect the Arduino board to the DHT22 sensor/module according to the provided diagram.
- Connect the Arduino board to your computer with a USB cable.
- Open Thonny IDE and go to Tools Options.
- Under the Interpreter tab, select MicroPython (generic) from the dropdown menu.
- Select the COM port corresponding to your Arduino board (e.g., COM33 on Windows or /dev/ttyACM0 on Linux).
- Copy the provided MicroPython code and paste it into Thonny\'s editor.
- Save the MicroPython code to your Arduino by:
- Clicking the Save button or pressing Ctrl+S.
- In the save dialog, choose MicroPython device and name the file main.py.
- Click the green Run button (or press F5) to execute the code.
- Change the temperature near the DHT22 sensor by making it warmer or cooler.
- Check out the message in the Shell at the bottom of Thonny.
Shell x
>>> %Run -c $EDITOR_CONTENT
MPY: soft reboot
Temperature: 19.00°C, Humidity: 44.00%
Temperature: 19.00°C, Humidity: 49.00%
Temperature: 19.00°C, Humidity: 54.00%
Temperature: 19.00°C, Humidity: 63.00%
Temperature: 20.00°C, Humidity: 74.00%
Temperature: 20.00°C, Humidity: 75.00%
Temperature: 21.00°C, Humidity: 76.00%
Temperature: 21.00°C, Humidity: 78.00%
Temperature: 22.00°C, Humidity: 79.00%
Temperature: 22.00°C, Humidity: 79.00%
Temperature: 23.00°C, Humidity: 79.00%
Temperature: 23.00°C, Humidity: 80.00%
MicroPython (generic) • Giga Virtual Comm Port in FS Mode @ COM33 ≡