HTU21D Module

This module contains the driver for MEAS HTU21D Relative Humidity and Temperature sensor. The HTU21D is capable of direct I2C communication and can be set on 4 different level of resolution in both temperature and humidity measurements (datasheet).

class HTU21D(i2cdrv, addr=0x40, clk=400000)

Creates an intance of a new HTU21D.

Parameters:

• i2cdrv – I2C Bus used ‘( I2C0, ... )’
• addr – Slave address, default 0x40
• clk – Clock speed, default 400kHz

Example:

from meas.htu21d import htu21d

...

htu = htu21d.HTU21D(I2C0)
htu.start()
htu.init()
t,h = htu.get_temp_humid()

init(res=0)

Initialize the HTU21D setting the resolution of the sensor.

Parameters:res – set the resolution (from 0 to 3) for temperature and humidity measurements according to the table below; default 0.

res value	Humid Resolution	Temp Resolution	Meas. Time Humid	Meas. Time Temp
0	12 bits	14 bits	16 ms	50 ms
1	8 bits	12 bits	3 ms	13 ms
2	10 bits	13 bits	5 ms	25 ms
3	11 bits	11 bits	8 ms	7 ms

get_raw_temp()

Retrieves the current temperature data from the sensor as raw value.

Returns raw_temp

get_raw_humid()

Retrieves the current humidity data from the sensor as raw value.

Returns raw_humid

get_temp()

Retrieves the current temperature data from the sensor as calibrate value in °C.

Returns temp

get_humid()

Retrieves the current relative humidity data from the sensor as calibrate value in %RH.

Returns humid

get_temp_humid()

Retrieves both temperature and humidity in one call.

Returns temp, humid