There is something strange about this . I'm looking into it
Now that is really interesting -Thank You
Your range is 148 degrees C
I'm thinking then that if your temps fall between -20 and + 30C say that range of 50 C only being used over the 1.1V could increase the accuracy even further?
I think you have got part of it, to clarify :-
1. The range is whatever is the range of LM35 sensor itself. Note : The LM35 sensor DC output varies in relation from 0-1V DC based on temp itself, NOT its input voltage
2. Because of the above, setting the max reference range of the ADC of the Uno board to 1.1V allow us to use almost
the entire 1024 (entire cause 1.1 = 1024, whereas the max we'll get is 1.0). If we had used 5 V, and the sensor output varied from 0-1.0 V, effectively you would have used only 1/5th the range of the ADC. i.e. you would not have got a reading of more that ~ 204 (vs approx 900-920 now, i.e. whatever the 1.0v corresponds to) , makes sense ?
3. Since the Reference range (using internal Uno reference) cannot be set below 1.1V, this is the max you can get the sensitivity to be.
4. however, if you decide to use an external reference source of say 0.5V, then what you are saying is possible.