A temperature-controlled fan automatically adjusts its speed based on the surrounding temperature. This project uses an LM35 temperature sensor and PWM (Pulse Width Modulation) control to regulate the ...

I used an LCD shield to display the current temperature and speed of the fan, but you can use the circuit without the LCD display. You also need to select the transistor by the type of fan that you ...

Alternatively, if the outside temperature is < desired temp, just blow air in regardless of the inside temp. All you need then is a temperature controlled fan.