Dht22 temperature and humidity sensor

I’ve got a dht22 sensor hooked up to my spark and working nicely with the adafruit library. I have a pull up resistor on my common.

It’s stable, goes up and down as expected.

My question is that I’m roughly 2 degrees Celsius above and 4-5% humidity below for all my readings. I’m comparing to 2 other commercial thermometer which are aligned. I also know that it’s not showing the right temp because you kind of know when it’s 71 or 73…

Right now I just adjust my readings with a constant and get what I think is right but I wanted to through it out to the community and see if anyone is experiencing the same.


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@apassemard is it very near the device on the breadboard/setup?

I think there might be a need for a capacitor to improve the ADC reading.

@mtnscott @peekay123 @ScruffR should have more experience with the DHT22 :wink:

@apassemard, if you search for DHT22 in the forum, you’ll find a lot of responses to your question. It turns out that with a DHT22 being near the Core, the heat of the Core will affect the readings of the sensor!


I experience similar inaccuracies until I used a high quality PSU such as a genuine Apple PSU, or perhaps you can use a large capacitor or some type of filtration.


I guess it’s just a bit too close to the Core… We’ll see what happens when it’s actually integrated in the device in the end. I’ll try to put it as far as possible.