Arduino controlled PWM PC Fan. Ask Question 2. 3 $ begingroup $. Browse other questions tagged arduino sensor pwm temperature fan or ask your own question. 5 years, 11 months ago. 24,535 times. 3 years, 3 months ago.

This application is simple just by using temperature sensor LM35 with an arduino kit to control a fan and change its speed with respect to the temperature read by the micro-controller which in this case is the arduino kit. The temperature sensor LM35 is connected with the arduino with an analog input pin A0 (the temperature is an analog signal), while the fan is connected with a PWM (Pulse Width Modulation) pin 6 which controls the speed of the fan with respect to the output temperature using a function map in the arduino IDE.

The Components needed: 1. Temperature Sensor LM35 3. 1K Resistor 4. Diode 1N4007 5. Dc Motor or a simple DC fan 6.

NPN transistor BC547 7. A voltage source with 12Volts 8. Hook up wires 9. Optional: voltage source socket.

Schematic •using the NPN transistor BC547 here as a buffer to isolate the first circuit which is the connection to the arduino and the other one with the fan. •using an inverted PN-junction parallel to the fan to prevent moving current in the opposite direction and make damage to the arduino kit. •using a PWM pin is to modulate the signal given to the fan with respect to the read temperature and by using the map function to control the fan speed. •it is important to put in consideration that the input voltage for the temp sensor is 5v from the arduino itself, and the 12volt voltage given to the motor or fan must be from an external voltage source, in this case we collect all the GND together weather the GND of the arduino and the external voltage source. You might've had this question answered, but for others who are curious - the fan is an inductive load, and the diode therefore serves as a 'flyback diode'. Technically, the fan's motor develops a magnetic field in order to spin. When the fan suddenly loses power (when you turn it off at the switch), it tries to 'feed itself' using the motor's collapsing magnetic field as its source, instead of the original source - which is now missing.

Depending on the magnitude of this field, the inductor creates a negaitve potential where it was once positive, and the inductive load tries to essentially 'force' the voltage across the power switch, creating an arc. This is dangerous for the circuit. A diode is therefore placed across the motor such that the intended source won't bypass the fan when operating, and the inductor will 'power itself down' PROPERLY (until it dies) when the fan is turned off.

Hope this helps:).

• GET Complete apparatus from • Subscribe to National Academy: Automatic Fan Introduction is one of the most popular electrical devices due to its cost effectiveness and low power consumption advantages. It is a common circuit and widely used in many applications. It is also one of the most sensible solutions to offer a comfortable and energy efficient. In fact, the fan has been long used and still available in the market. Nowadays, the demand for accurate temperature control and air freshening control has conquered many of industrial domains such as process heat, automotive, industrial places or office buildings where the air is cooled in order to maintain a comfortable environment for its occupants. One of the most important concerns involved in heat area consist in the desired temperature achievement and consumption optimization. Fan can be controlled manually by pressing on the switch button.

Where in this method, any change in the temperature will not give any change in the fan speed. Except the usage change the speed of the fan which is manually. So, an automatic temperature control system technology is needed for the controlling purpose in the fan speed according to the temperature changes. Automatic Fan Control for Air Conditioning System The automatic air conditioning system can be done by using Electronic circuit using Microprocessor or microcontrollers. Now is advanced among all above circuits therefore we are using microcontrollers for air conditioning such as the This system designed with microcontroller, FAN, temperature senso and a DC motor.

The temperature sensor is used to detect the temperature of that environment and send that information to the ADC then that result sends to the microcontroller. Then the microcontroller performs the comparison of current temperature and set temperature as per the logic of the program for which microcontroller has already been programmed. The result obtained from the above operation is given through output port of a microcontroller to the LCD display of relevant data and generated pulses as per the logic program which is further fed to the driver circuit to obtain the desired output to fan. Advantages of Air Conditional Fan The advantages of automatic fan control for air conditioning system mainly include the following. • Quick cooling • More cooling and less moisture removable • Good for daytime, when cooling loads are low and humidity high • Energy efficient, partly because it removes less moisture • Low speed settings • More moisture removable • Lower fan noise and quieter operations • Good for nighttime, when cooling loads are low and humidity is high • Increased comfort level • Slight loss in efficiency Working of Automatic Fan In this based project, we are going to control DC fan speed according to the room temperature and show these parameter changes on a 16x2 LCD display. It is accomplished by the data communications between Arduino, LCD, sensor Module and DC fan that is controlled by using PWM.