Introduction

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CircuitPython module for the SHT31-D temperature and humidity sensor.

Dependencies

This driver depends on:

Please ensure all dependencies are available on the CircuitPython filesystem. This is easily achieved by downloading the Adafruit library and driver bundle.

Installing from PyPI

On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally from PyPI. To install for current user:

pip3 install adafruit-circuitpython-sht31d

To install system-wide (this may be required in some cases):

sudo pip3 install adafruit-circuitpython-sht31d

To install in a virtual environment in your current project:

mkdir project-name && cd project-name
python3 -m venv .env
source .env/bin/activate
pip3 install adafruit-circuitpython-sht31d

Usage Example

You must import the library to use it:

import adafruit_sht31d

This driver takes an instantiated and active I2C object (from the busio or the bitbangio library) as an argument to its constructor. The way to create an I2C object depends on the board you are using. For boards with labeled SCL and SDA pins, you can:

from busio import I2C
from board import SCL, SDA

i2c = I2C(SCL, SDA)

Once you have created the I2C interface object, you can use it to instantiate the sensor object:

sensor = adafruit_sht31d.SHT31D(i2c)

And then you can start measuring the temperature and humidity:

print(sensor.temperature)
print(sensor.relative_humidity)

You can instruct the sensor to periodically measure the temperature and humidity, storing the result in its internal cache:

sensor.mode = adafruit_sht31d.MODE_PERIODIC

You can adjust the frequency at which the sensor periodically gathers data to: 0.5, 1, 2, 4 or 10 Hz. The following adjusts the frequency to 2 Hz:

sensor.frequency = adafruit_sht31d.FREQUENCY_2

The sensor is capable of storing eight results. The sensor stores these results in an internal FILO cache. Retrieving these results is simlilar to taking a measurement. The sensor clears its cache once the stored data is read. The sensor always returns eight data points. The list of results is backfilled with the maximum output values of 130.0 ºC and 100.01831417975366 % RH:

print(sensor.temperature)
print(sensor.relative_humidity)

The sensor will continue to collect data at the set interval until it is returned to single shot data acquisition mode:

sensor.mode = adafruit_sht31d.MODE_SINGLE

Contributing

Contributions are welcome! Please read our Code of Conduct before contributing to help this project stay welcoming.

Documentation

For information on building library documentation, please check out this guide.

Table of Contents

Simple test

Ensure your device works with this simple test.

examples/sht31d_simpletest.py
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import time
import board
import busio
import adafruit_sht31d

# Create library object using our Bus I2C port
i2c = busio.I2C(board.SCL, board.SDA)
sensor = adafruit_sht31d.SHT31D(i2c)

loopcount = 0
while True:
    print("\nTemperature: %0.1f C" % sensor.temperature)
    print("Humidity: %0.1f %%" % sensor.relative_humidity)
    loopcount += 1
    time.sleep(2)
    # every 10 passes turn on the heater for 1 second
    if loopcount == 10:
        loopcount = 0
        sensor.heater = True
        print("Sensor Heater status =", sensor.heater)
        time.sleep(1)
        sensor.heater = False
        print("Sensor Heater status =", sensor.heater)

adafruit_sht31d

This is a CircuitPython driver for the SHT31-D temperature and humidity sensor.

  • Author(s): Jerry Needell, Llewelyn Trahaearn

Implementation Notes

Hardware:

Software and Dependencies:

class adafruit_sht31d.SHT31D(i2c_bus, address=68)[source]

A driver for the SHT31-D temperature and humidity sensor.

Parameters:
  • i2c_bus – The busio.I2C object to use. This is the only required parameter.
  • address (int) – (optional) The I2C address of the device.
art

Control accelerated response time This feature only affects ‘Periodic’ mode.

clock_stretching

Control clock stretching. This feature only affects ‘Single’ mode.

frequency

Periodic data acquisition frequency Allowed values are the constants FREQUENCY_* Frequency can not be modified when ART is enabled

heater

Control device’s internal heater.

mode

Operation mode Allowed values are the constants MODE_* Return the device to ‘Single’ mode to stop periodic data acquisition and allow it to sleep.

relative_humidity

The measured relative humidity in percent. ‘Single’ mode reads and returns the current humidity as a float. ‘Periodic’ mode returns the most recent readings available from the sensor’s cache in a FILO list of eight floats. This list is backfilled with with the sensor’s maximum output of 100.01831417975366 when the sensor is read before the cache is full.

repeatability

Repeatability Allowed values are the constants REP_*

serial_number

Device serial number.

status

Device status.

temperature

The measured temperature in degrees celsius. ‘Single’ mode reads and returns the current temperature as a float. ‘Periodic’ mode returns the most recent readings available from the sensor’s cache in a FILO list of eight floats. This list is backfilled with with the sensor’s maximum output of 130.0 when the sensor is read before the cache is full.

Indices and tables