Htu21d your experience with accuracy

[vojtishek]

Hi all, I've connected htu21d with wemosd1 mini. Sensor Is outside box, So no heat from chip. But still temperature higher then should be in comparsion with reality. Specifically +2, +3 C°. This is quite huge as I was in feeling this sensor Is more accurate then dht22.
Could you please share your experience?
Thanks
Vojta

[Drum]

The datasheet says +-0.3 C. What are you using as a comparison? If you are using something that accurate, and calibrated is getting 2 to 3 C off I would wonder if you have a bad or not genuine sensor. Assuming you have it connected properly.

The datasheet says it should have pull-up resistors on the data wires and 100 nF decoupling capacitor between VDD and GND as close to the sensor as possible.

[TD-er]

Also, how often do you sample the device?
I noticed other sensors like the Bosch BME280 and BMP280 will heat up up-to 2 degrees by only sampling continuously.
I created a pull request to combine these two, but also put them to sleep for almost a minute, which helps a lot in measurement offset.

[Shardan]

I have the same deviations with these sensors (and some similiar sensors too).

The HTU21D is a combined temperature/humidity sensor.
Humidity sensors need a heating now and then to dry the humidity sensor brom moisture.

I assume that the heating is not controlled by the ESP plugin and running permanently.

This should be corrected in the plugin source.

Regards
Shardan