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DHT22 technical questions about sleep mode and protocol


I got a few questions about the DHT22.
1) How can i get the DHT22 in stand by mode? leave the dataline high or low or does i need to send a code?
2) when i receive all data and i keep the dataline low, for how long does i need to keep the dataline high before i send the start signal?

thnx for the reaction

1 Answer



As long as you do not make a request the DHT11/22 should remain in its lowest power mode (for all intents and purposes standby).
The DHT11 and DHT22 only update every two seconds, and the start signal is 18 milliseconds Low followed by 40 milliseconds High.
If you need any more information on the protocol check out this reference section on the site:
If you wanted to go crazy you could turn the DHT22 on and off using a transistor following these video guides (just replace the LED with your DHT22’s power)
Joseph Dattilo

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