DHT22 no reading

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ulfh2018
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Posts: 39
Joined: 19 Feb 2018, 06:11
Location: Oslo Norway

DHT22 no reading

#1 Post by ulfh2018 » 29 Sep 2018, 13:48

I have just received a bunch of DHT22, which I use to get temperature and humidity from various rooms in the house. I have used GPIO 2 to read from the DHT22, but occationally the reading fails, and I get "no reading" if I check using a serian connection and a terminal emulator. If I connect another DHT22, most of the time this will work, and if I then plug back the one that failed, it will now work as expected.

I am using ESP_Easy_mega-20180924_normal_ESP8266_4096.bin as the boot image, and the hardware is Wemos ESP-12F.

Any clues about what might be wrong?

All the best from

Ulf

Strider336
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Posts: 14
Joined: 13 Jan 2018, 11:51

Re: DHT22 no reading

#2 Post by Strider336 » 14 Oct 2018, 12:58

If it's been wired incorrectly it's probably permanently dead.

If it's been wired correctly, try assigning a random IDX value, i've actually got a note in my projects file, called DS18B20_DHT22.txt telling me that both DS18B20 and the DHT22 won't read anything without an IDX. I don't know if that is true, but something about going through that process does seem to fix the problem.

Also check the formula entry says %value% with an L, not %vaIue% with an I, that little typo had me going around in circles for hours :p

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