I'm building a humidity monitor and plan on using and Arduino UNO to measure temperature and humidity from a Digital-output relative humidity & temperature sensor/module AM2303 (SMAKN DHT22).
Here's a link to the sensor
SMAKN® DHT22 AM2302 Digital Temperature And Humidity Measurement Sensor
My question is, can the sensor (and the Arduino UNO) be left on for years? This unit claims "Excellent long-term stability" but I'm not sure what long means--and the data sheet doesn't say either.
KrisKasprzak:
My question is, can the sensor (and the Arduino UNO) be left on for years?
Yes, an Arduino can run 24 hours a day, 7 days a week. As well as the sensor can.
But the DHT22 is just a China made cheapy-cheapy sensor.
This sensor is famous for its very low price and not for its very high quality.
Usage time is very much dependent on the environmental conditions.
Especially the humidity measurement can be ruined within several months of usage in (even protected) outdoor conditions: High levels of dust and high levels (>95%) of humidity in the air will lead to degrading accuracy of the humidity measurement within a few months. May be better for indoor usage only. In harsh conditions you better be prepared to replace the sensor from time to time.
"Excellent long-term stability" is probably a translation error as far as it refers to "humidity" measurement in outdoor conditions. Or it refers to the casing only, which does not fall into pieces after years of usage.
We have a few on the boards in air quality monitors. These have been in ducts and in service
for over 15 years now. They seem to be accurate (not calibrated in any way just installed)
and still very reactive (30 seconds to respond to duct humidifiers).