Closed Diederikvanderpant closed 6 years ago
Good question.
The HTU21D datasheet from 2014, see row "Temperature coefficient" in the table on page 3.
Hi,
Thanks for the answer! Out of curiosity. How did you find out that HTUD21D from MEAS and SHT21 from Sensirion are identical? Googling, it seems a lot of people know about this. But their datasheets do not mention each other....
Sincerely,
Deiderik
2017-04-12 14:03 GMT+02:00 enjoyneering notifications@github.com:
Good question.
The HTU21D datasheet from 2014, see row "Temperature coefficient" in the table on page 3.
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Hi, Deiderik
Take a look at Grath 1 on p. 4 of HTU21D datasheet and Figure 2 on p.2 of SHT21 . They are identical, plus returning the same chip ID, see readDeviceID() function.
The Si7021 is completely different beast. It's RH accuracy a little bit better, Figure 2 on p.8. And it looks like it does temp. compensation automatically, see readTemperature(HTU21D_TEMP_READ_AFTER_RH_MEASURMENT)). You have to call it after RH measurement.
All three sensors are very accurate and reliable, however if you just starting the project I'am suggesting BME280. See the article.
Hi, Thanks for the quick reply. Will use your code in a testsetup with sht21's i am running. Btw in another setup i am also very satisfied with the performance of sht31 and bme280 who have Tcompensation integrated. Sincerely, Diederik
Op 12 apr. 2017 17:56 schreef "enjoyneering" notifications@github.com:
Hi, Deiderik
Take a look at Grath 1 at p. 4 of HTU21D datasheet and Figure 2 at p.2 of SHT21 . They are identical, plus returning the same chip ID, see readDeviceID() function.
The Si7021 is completely different beast. It's RH accuracy a little bit better, Figure 2 at p.8. And it looks like it does temp. compensation automatically, see readTemperature(HTU21D_TEMP_READ_AFTER_RH_MEASURMENT)). You have to call it after RH measurement.
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Hi,
What is your source for the temperature compensation of the humidity at line 418 in HTU21D.CPP . You claim it is valid for the SHT21 but I cannot any reference in the Sensirion datasheets for the SHT21.
Sincerely, Diederik vd Pant