SHT30 Sensor driver in micropython

Micropython driver for SHT30 Shield for Wemos D1 Mini (and PRO).

The driver has been tested on Wemos D1 mini PRO, but it should work on whatever other micropython board, if anyone find problems in other boards, please open an issue and we'll see.

Motivation

The SHT30 shield for ESP8266 board Wemos D1 Mini has an Arduino driver but not a micropython one.

References:

• Sensor Datasheet
• Arduino driver
• SHT30 C Code Examples from sensor manufacturer

Examples of use:

How to get the temperature and relative humidity:

The measure() method returns a tuple with the temperature in degrees Celsius and the relative humidity in percentage. If the measurement cannot be performed then an exception is raised (SHT30Error)

from sht30 import SHT30

sensor = SHT30()

temperature, humidity = sensor.measure()

print('Temperature:', temperature, '°C, RH:', humidity, '%')

The measure_dp() method returns a similar tuple but with the dew point temperature (i.e. the temperature at which dew will form if the air is cooled adiabatically) instead of relative humidity. Both values are degrees Celsius.

from sht30 import SHT30

sensor = SHT30()

temperature, dew_point = sensor.measure_dp()
print('Temperature:', temperature, '°C, dew point:', dew_point, '°C')

There is another method, measure_int(), that returns 4 integer values, no floating point operation is done, designed for environments that doesn't support floating point operations, the four values are:

Temperature (integer part), Temperature (decimal part), RH (integer part), RH (decimal part)

For instance, if the measure() method returns (21.5623, 32.0712) the measure_int() method would return: (24, 56, 32, 7) The decimal part is limited to 2 decimal digits.

t_int, t_dec, h_int, h_dec = sensor.measure_int()

print('Temperature: %i.%02i °C, RH: %i.%02i %%' % (t_int, t_dec, h_int, h_dec))

Both methods allow a raw param that when it's True returns the sensor measurement as-is, it's a bytearray(6) with the format defined in the sensor datasheet document.

raw_measure = sensor.measure(raw=True)

print('Sensor measurement', raw_measure)

Check if shield is connected

from sht30 import SHT30

sensor = SHT30()

print('Is connected:', sensor.is_present())

Read sensor status

Check the Sensor Datasheet for further info about sensor status register

from sht30 import SHT30

sensor = SHT30()

print('Status register:', bin(sensor.status()))
print('Single bit check, HEATER_MASK:', bool(sensor.status() & SHT30.HEATER_MASK))

# The status register can be cleared with
sensor.clear_status()

Reset the sensor

The driver allows a soft reset of the sensor

from sht30 import SHT30

sensor = SHT30()
sensor.reset()

Error management

When the driver cannot access the sensor an SHT30Error exception is raised

from sht30 import SHT30

sensor = SHT30()

try:
    t, h = sensor.measure()
except SHT30Error as ex:
    print('Error:', ex)