I have a DHT22 temperature sensor and DS1302 RTC module connected to the 3v3 pins on an Arduino Nano. Both the sensor and the RTC module are rated to work on either 3.3V or 5V, but the recommendation is 3.3V. For some reason though, when I connect the sensor and RTC to 3.3V power on the Nano, the sensor just returns NaN even though the RTC module works. When I change the sensor to use 5V and leave the RTC on 3.3V, I get a proper temp and humidity value on the DHT22. What is wrong?

Turns out the solder joint for the 3v3 pin on the nano was not properly done. I figured this out after I swapped out the nano for another nano and it worked. Resoldering the 3v3 pin fixed the problem.

1 Answer 1


Sometimes the problem is simply that you didn't properly solder the headers onto the Arduino. You should check to make sure that your solder joints are all good.

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