The research paper presented here is based on automatic fan speed controller that automatically adjusts the fan's speed according to ambient temperature of the surroundings. The temperature flow controlled fan is an automated fan, controlled by a temperature sensor, using fully hardware design. The heart of this project consists of the temperature sensor circuit which senses the change in the ambient temperature of the surroundings. As the signal sensed by the temperature sensor is very weak in amplitude and strength. Therefore we use amplifier to increase the strength of the signal so that the signal is able to drive the output section, in this case a fan. Here pulse width modulation is use in this case. When heat is applied to the temperature sensor, this will determine the fan automatically increasing or decreasing in speed according to the four speed levels of a normal fan that are set to different temperature ranges of a room. It can be used in cooling electronics devices, where the fan speed needs to increase if here dissipation increases.