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This is an older sensor it is not the new ones we have been comparing to, ours has the 31 digital sensor.
I know it has been awhile, but here is the update:I originally purchased two SHT35-DIS modules. Along with writing code to emulate the ISS, I also wrote stand alone code for them. They have been running for months, one with a filter and one without. I am convinced that they both exhibit the same "wetness" that the other Sensirion sensors do. I guess that given that the spec sheet states the following:QuoteThe sensor shows best performance when operated within recommended normal temperature and humidity range of 5 °C– 60 °C and 20 %RH – 80 %RH, respectively. Long-term exposure to conditions outside normal range, especially at highhumidity, may temporarily offset the RH signal (e.g. +3%RH after 60h kept at >80%RH). After returning into the normaltemperature and humidity range the sensor will slowly come back to calibration state by itself.The results I got are to be expected. The above quote applies to the newer SHT85 as well. Maybe it is just in the packaging, my inexpensive AcuRite doesn't do this!My results may seem disappointing, but all of my time wasn't wasted. The same concept could be applied to any other sensor whether it be analog, I2C or other. I/we just need to come up with a sensor that truly works well outdoors.Maybe the HYT series is worth looking into.....
The sensor shows best performance when operated within recommended normal temperature and humidity range of 5 °C– 60 °C and 20 %RH – 80 %RH, respectively. Long-term exposure to conditions outside normal range, especially at highhumidity, may temporarily offset the RH signal (e.g. +3%RH after 60h kept at >80%RH). After returning into the normaltemperature and humidity range the sensor will slowly come back to calibration state by itself.
Just did a quick google search for Hygrosense (makers of the HYT 221) versus Senserion and found this on a Arduino forum. Just hearsay but I guess it could be another reason to mess around with the hyt class sensors."Ciao,I have both Sensirion and IST (Hygrosens) sensors.IST one has better accuracy and is I2C (easier to use), Sensirion has better control over data sent (CRC).Since the products are in IST AG portfolio these sensors are easier to find (IST is the Swiss company that produce thin film sensors).Thery also produce great digital temperature sensors with better accuracy than Dallas 18B20.http://www.ist-ag.com/In USA You can find IST prodcuts at www.servoflo.com .In Europe from Schukat.comhttp://www.schukat.com/schukat/schukat_cms_en.nsf/index/CMSDF15D356B046D53BC1256D550038A9E0?OpenDocument&wg=A2645&refDoc=CMS83E9AF7D7863AC9FC125711E004F71BEBeware that prices variation in very high.conrad.comhttp://www.conrad.com/DIGITAL-HUMIDITY-SENSOR-HYT-221.htm?websale7=conrad-int&pi=505671&ci=SHOP_AREA_14741_0231310I had my I2C address changed directly by the manufacturer last year (I purchased 3 for a project), anyway I have been said that there is a procedure to change it.Maybe You can contact IST.Ciao,Marco."
Quote from: hwcorder on February 03, 2019, 02:36:42 PMJust did a quick google search for Hygrosense (makers of the HYT 221) versus Senserion and found this on a Arduino forum. Just hearsay but I guess it could be another reason to mess around with the hyt class sensors."Ciao,I have both Sensirion and IST (Hygrosens) sensors.IST one has better accuracy and is I2C (easier to use), Sensirion has better control over data sent (CRC).Since the products are in IST AG portfolio these sensors are easier to find (IST is the Swiss company that produce thin film sensors).Thery also produce great digital temperature sensors with better accuracy than Dallas 18B20.http://www.ist-ag.com/In USA You can find IST prodcuts at www.servoflo.com .In Europe from Schukat.comhttp://www.schukat.com/schukat/schukat_cms_en.nsf/index/CMSDF15D356B046D53BC1256D550038A9E0?OpenDocument&wg=A2645&refDoc=CMS83E9AF7D7863AC9FC125711E004F71BEBeware that prices variation in very high.conrad.comhttp://www.conrad.com/DIGITAL-HUMIDITY-SENSOR-HYT-221.htm?websale7=conrad-int&pi=505671&ci=SHOP_AREA_14741_0231310I had my I2C address changed directly by the manufacturer last year (I purchased 3 for a project), anyway I have been said that there is a procedure to change it.Maybe You can contact IST.Ciao,Marco."I’m ignorant here...but what does he means that Sensirion has better control over the data sent?
CRC is error checking so lower probability of spurious values being treated as valid.
Mouser now has the SHT85 in stock. I ordered several to play with. We'll see........
