This isn’t about connecting a temperature sensor in your Arduino. ... The temp sensor 3 pin devices are simple and cheap but good for 0.5 deg C precision or nearly a full degree in human measure.

3-pin fans still have an RPM sensor on them, and most mainboards can still vary their speed based on temperature. 3-pin fans use simple voltage control for adjust the fan speed. 4-pin units ...

This project demonstrates a system using two Arduino boards, an LM35 temperature sensor, and an L298N motor driver to control a DC motor's speed and direction based on temperature readings. The setup ...