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DHT22 quits working

Q&A Forum › Category: ESP8266 › DHT22 quits working
0 Vote Up Vote Down
Rick Lutz asked 6 years ago

My DHT 22 quits responding if I reset the ESP8266.  It will only start responding if I cycle the 3.3V to the DHT.  I can see the DHT is getting the start pulse but does not return the data string until I cycle the DHT power.  After cycling DHT power it works continuously. 
Only running sample DHT code from ADAfruit

Question Tags: DHT22 power cycle
5 Answers
0 Vote Up Vote Down
Sara Santos Staff answered 6 years ago

Hi Rick.
Can you tell me the connections between your ESP8266 and the DHT22?
And what ESP8266 model are you using?
Regards,
Sara

0 Vote Up Vote Down
Rick Lutz answered 6 years ago

LoLin NodeMCU V3 – I assume ESP8266-12E.
DHT board had resistor built in 
DHT-1=3.3V, DHT-3=Gnd, DHT-2=D4(GPIO2)

0 Vote Up Vote Down
Sara Santos Staff answered 6 years ago

Hi Rick.
Can you connect pin 2 to another GPIO? Try GPIO4.
GPIO 2 is HIGH at boot, which can interfere with the readings: https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/
Regards,
Sara
 

0 Vote Up Vote Down
Rick Lutz answered 6 years ago

Sara, thank you that was it.  I was using GPIO 4 and 5 for web control, I will do some re-writing/connecting.  

0 Vote Up Vote Down
Sara Santos Staff answered 6 years ago

Great!
I’m glad the problem is solved.
Regards,
Sara 😀

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