I did develop some professional temperature measurement equipment with 24 bit Analog Devices ADCs, ratiometric measurement and high precision PT1000 sensors and I was happy to get 0.1°C accuracy ...

I have done e similar project with Arduino and tow sensors – BMP085 for atmospheric pressure and the other one DHT for the humidity levels with both sensors measuring temperature. Soon I’ll ...

You also need to select the transistor by the type of fan that you use. In my case I used the well-known BD139 transistor and a 9V battery to provide power to the fan and transistor. The LM35 ...