DHT22 works on PI2 but not PI4

Moderators: adafruit_support_bill, adafruit

Forum rules
If you're posting code, please make sure your code does not include your Adafruit IO Active Key or WiFi network credentials.
Locked
User avatar
FruitIncognito
 
Posts: 2
Joined: Fri Aug 20, 2021 11:06 am

DHT22 works on PI2 but not PI4

Post by FruitIncognito »

Hello, I have a Raspberry PI 2 and a couple new PI 4s. I have been using a DHT22 connected to the PI2 successfully using Adafruit/examples/AdafruitDHT.py successfully.
I connect power to pin 1, data to pin 7 (gpio4) and ground to pin 9. running the script it returns temperature and humidity using sudo python AdafruitDHT.py 22 4.
The problem is when I connect the same and run the same on a couple different PI 4s it does not work.

Is there something different about the PI4? I have tried other GPIO pins on the PI 4s unsuccessfully and tested successfully on the PI2 with other pins.

User avatar
adafruit2
 
Posts: 22145
Joined: Fri Mar 11, 2005 7:36 pm

Re: DHT22 works on PI2 but not PI4

Post by adafruit2 »

DHT22 is really really annoying to use. please use a different sensor, like the AHT20
https://www.adafruit.com/product/5183

User avatar
FruitIncognito
 
Posts: 2
Joined: Fri Aug 20, 2021 11:06 am

Re: DHT22 works on PI2 but not PI4

Post by FruitIncognito »

Okay I get your recommendation, thank you for that. It would be helpful to understand what is different. Why does the DHT22 work just fine on an older raspberry PI but not on a pi4. What is different?

User avatar
adafruit2
 
Posts: 22145
Joined: Fri Mar 11, 2005 7:36 pm

Re: DHT22 works on PI2 but not PI4

Post by adafruit2 »

linux just doesn't work well with this sensor, it is timing specific

Locked
Forum rules
If you're posting code, please make sure your code does not include your Adafruit IO Active Key or WiFi network credentials.

Return to “Internet of Things: Adafruit IO and Wippersnapper”