In the past ~5 months I have changed the AM2302 twice

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sibianul
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In the past ~5 months I have changed the AM2302 twice

#1 Post by sibianul » 04 Nov 2017, 10:23

Hello guys,

Do you have success using the AM2302 sensor in a long term application? I mounted one in my bathroom and recently I noticed the second sensor (the first one failed about 2 months ago) doesn't report any reading, if I check the ESP, it's working but on the DEVICE tab, both values for temperature and humidity are nan.

I have purchased some other sensors too, one identical sensor seems to have the 2 components inside better soldered, with shorter legs, and better aligned, this should affect the functionality, but maybe the 3rd sensor, wich I told you is better soldlered, is using using better components? Should I try to solder again, the exact same type of sensor AM2302 ? Or should I move on to another type of sensor, currently I have BM280 and AM2302B (this one has a huge case) ???

In the photo bellow , the left one is the first one that failed (I did not tryed to test it with another board, I just swaped it with an identical one and everything worked ok, for about 2 months, and now that second one is not reporting any values).

The sensors and ESP are powered 24/7, I haven't used the sleep function.
humidity temperature sensor.jpg
humidity temperature sensor.jpg (72.2 KiB) Viewed 5531 times

TD-er
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Re: In the past ~5 months I have changed the AM2302 twice

#2 Post by TD-er » 04 Nov 2017, 11:12

Did you also try to disconnect the sensor for a while and then try again? (and/or reboot the ESPeasy)

papperone
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Re: In the past ~5 months I have changed the AM2302 twice

#3 Post by papperone » 04 Nov 2017, 13:42

I've either DHT22 (very similar to AM2302) and DS18B20 running 24x7 in various places in my house (some more than 1 year) and none of them failed so far...
My TINDIE Store where you can find all ESP8266 boards I manufacture --> https://www.tindie.com/stores/GiovanniCas/
My Wiki Project page with self-made PCB/devices --> https://www.letscontrolit.com/wiki/inde ... :Papperone

Shardan
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Re: In the past ~5 months I have changed the AM2302 twice

#4 Post by Shardan » 04 Nov 2017, 16:27

Just for curiosity:
Can you please take the broken sensors and put them in a dry place for a while (2..3 days)?
Then check if they start working again.

I've seen some rumours about the humidity sensor inside the DHT22 (AM2302 is same, just wires instead of pins).
The sensor uses a capacitor that is sensitive to humidity. The capacitor uses a polymer dielectric.
These rumours say that the polymer soaks water and swells up, stopping the sensor from work if the humidity
is somewhat high. As you're using it in the bathroom this might be the reason.

I'm using the SI7021/HTU21 in my bathroom for a year now running nicely.

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Shardan
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sibianul
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Re: In the past ~5 months I have changed the AM2302 twice

#5 Post by sibianul » 05 Nov 2017, 18:29

TD-er wrote: 04 Nov 2017, 11:12 Did you also try to disconnect the sensor for a while and then try again? (and/or reboot the ESPeasy)
I made a stupid case for that sensor, and also the humidity sensor has the wires soldered to a board, so I can do this if I remove the sensor from the bathroom for a few days. I will do this to see if anything changes.
papperone wrote: 04 Nov 2017, 13:42 I've either DHT22 (very similar to AM2302) and DS18B20 running 24x7 in various places in my house (some more than 1 year) and none of them failed so far...
I also have other DS18B20 sensors in the hot water tank and another one in an outdoor box, where I keep a raspberyPi and a FlightRadar24 box, also a switch and a 5 v power supply, those sensors are all good, never had a problem, only with those in the bathroom.
Shardan wrote: 04 Nov 2017, 16:27 Just for curiosity:
Can you please take the broken sensors and put them in a dry place for a while (2..3 days)?
Then check if they start working again.
The first sensor that failed is in my office, laying around my keyboard, maybe I should plug it in a breadboard and connect it with an controller to see if it reads anything, this was remove from my bathroom now about 2 months ago, so plenty of time to dry up.

I will post back in a few days, as tomorrow I will be away all day and can't do any tests.

This is how the graphs looks for the last reports
bathroom sensors last reports.jpg
bathroom sensors last reports.jpg (70.62 KiB) Viewed 5491 times

sibianul
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Re: In the past ~5 months I have changed the AM2302 twice

#6 Post by sibianul » 11 Nov 2017, 15:12

Advices are welcome !

This morning I removed the 220v power wire from that module , and left it unplugged for more than 8 hours, now I plugged it back in an to my surprise, everything works just fine. I know for sure that when the first sensor stoped reporting humidy and temperature values, I did turned it off and than back on, and it didn;t worked after that, it was just a quick turn off / turn on. It seems that now, after I let the sensor off for more hours, it worked when powered back on.

What could be the cause ?

How to prevent ?
temperature and humidity working again.jpg
temperature and humidity working again.jpg (21.54 KiB) Viewed 5434 times

Drum
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Re: In the past ~5 months I have changed the AM2302 twice

#7 Post by Drum » 14 Nov 2017, 16:43

Condensation might be an Issue. Per spec sheet:

Step one: Keep the AM2302 sensor at condition of Temperature 50~60Celsius, humidity <10%RH for 2 hours;
Step two: After step one, keep the AM2302 sensor at condition of Temperature 20~30Celsius, humidity
>70%RH for 5 hours.

I need to look at some of the commercial outdoor humidity sensors to see what they are using and how they are protecting the circuitry. After a few months outside I get a lot of corrosion.

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