I had some LM35 temperature sensors laying around. And tried to hook one up to the imp. Its directly hooked up to
GND, 3v3 and pin9.
IT WORKS!? Why!? The LM35 requires minimum 4v to operate, so why can I get valid readings with only 3v3?
See the attached datasheet graph of minimum supply voltage vs temperature.
does that mean it can only measure up to around 25-30 C???
Chip specs are the guaranteed operating conditions. They may work, to some extent, at lower voltages but you’ll likely find that it’s not actually working very well (accuracy, etc).