i got a DHT22 in my weather station.
As tempatures are slowly going below freezing point (0 degrees celsius) at night here in germany, i discovered a problem with the sensor's Arduino Class
When the temperature drops below 0°C (for exampe -1°C) the Class gives me exactly 0°C at all times.
I figured out the class got an update regarding to this issue 4 month ago, so i updated the class and re-uploaded my sketch to the board.
Now, when the temperature drops below 0°C, i get something like 3275.3°C from the class. (but everythink ok with positive temperatures)
As the variable inside the class is working with integers, i remembered the maximum integer value is 32767.
So real my temperature is probalby 32767 (max int. value) - 32753 (value the class gives me) = 14 = 1.4 = the real -1.4°C
It seems to me something causes the integer value to overflow, but i don't know how to solve this...
Ok, as i'm sending the measured values every 10 minutes to a webserver, i could just calculate the real negative temperature,
but that didn't solve the problem on the roots.