I have a temperature sensor that outputs a certain voltage to the Arduino. I then convert it to analog by using the equation given in the datasheet to output the correct temperature to an LCD screen. When I have my Arduino hooked up, it outputs the exact temperature it is supposed to. When I take the Atmega328 and use it alone from the Arduino, it outputs about 8 degrees off. The temperature sensor itself is still outputting the correct voltage as it's supposed to! But the print is off. I'm using a 5V input to the Atmega328.
I'm using this schematic to use with my Atmega328. Is there anything else I need with this schematic that might affect the analog inputs?
Thank you very much in advance.