DHT12 sensor driver

This module provides a MicroPython driver for the Aosong DHT12 temperature and humidity sensor, which communicates over I2C. It includes classes and methods for reading temperature and humidity data from the sensor.

Classes

• DHTBaseI2C : Base class for handling low-level I2C communication with the DHT12 sensor.

• DHT1 : Extends DHTBaseI2C to provide methods for reading temperature and humidity values.

Attributes

• SENSOR_ADDR : The default I2C address (0x5c) of the DHT12 sensor.

Example

from dht12 import DHT12
from machine import I2C, Pin

# Initialize I2C interface
i2c = I2C(0, scl=Pin(22), sda=Pin(21))

# Create an instance of the DHT12 sensor
sensor = DHT12(i2c)

# Read and print temperature and humidity values
temperature, humidity = sensor.read_values()
print(f"Temperature: {temperature} °C, Humidity: {humidity} %")

Authors

• Mike Causer, PyPI

• Tomas Fryza

Modification history

• 2024-11-11 : Added Sphinx comments.

• 2024-11-02 : Added read_values method.

• 2023-11-10 : Added scan method.

class dht12.DHT12(i2c, addr=92)

Bases: DHTBaseI2C

humidity()

Calculates and returns the humidity as a floating-point value, using data previously read into the buffer (self.buf) by the measure method.

Returns:

The current humidity as a percentage.

Example:

sensor = DHT12(i2c)
sensor.measure()  # Read data from sensor
humidity = sensor.humidity()
print(f"Humidity: {humidity} %")

read_values()

Read temperature and humidity from the sensor.

Returns:

A tuple containing the temperature (float) and humidity (float) values.

temperature()

Calculates and returns the temperature in degrees Celsius as a floating-point value, using data stored in the buffer (self.buf) by the measure method. It interprets both positive and negative temperatures.

Returns:

The current temperature in degrees Celsius.

Example:

sensor = DHT12(i2c)
sensor.measure()  # Read data from sensor
temperature = sensor.temperature()
print(f"Temperature: {temperature} °C")

class dht12.DHTBaseI2C(i2c, addr=92)

Bases: object

measure()

Reads 5 bytes of data from the DHT12 sensor’s memory and performs a checksum validation to ensure data integrity. The retrieved data is stored in the buffer (self.buf). If the checksum validation fails, an exception is raised.

Raises:

Exception – If the checksum validation fails, indicating potential data corruption.

Example:

sensor = DHT12(i2c)
try:
    sensor.measure()
    print("Data read successfully.")
except Exception as e:
    print("Checksum error:", e)

scan()

Checks if the DHT12 sensor is available on the I2C bus by scanning for its specified address (SENSOR_ADDR). If the sensor is not found, it raises an exception.

Raises:

Exception – If the sensor address (SENSOR_ADDR) is not detected on the I2C bus.

Example:

sensor = DHT12(i2c)
try:
    sensor.scan()
    print("Sensor detected.")
except Exception as e:
    print(e)