Oh yeah, and on the ‘time constant’ thing:
There’s no point in doing your samples more often than 1 or 2 times per second. Any temperature sensor (of this type) has a ‘thermal mass’, which means that when you expose it to a new temperature, it takes time for it to change, because the body of the sensor has to change to match the external temperature.
Imagine a traditional thermometer that contains a liquid in a glass tube. If you put your finger on the bulb, it doesn’t instantly shoot up to a higher value - it goes up gradually.
I suppose an IR sensor avoids the thermal mass issue…
Pete