A low frequency pulse width modulation pwm signal whose duty cycle is varied to adjust the fan s speed is used.
Arduino pwm fan controller.
Design schematic diagram is shown next.
I simply want to control a 4 wired fan or maybe several with an arduino board.
The ultimate project is to control the fan based on temperature.
The frequency values can be adjusted between 125 hz 8 mhz as well as a variable duty cycle.
Temperature based fan speed control monitoring with arduino.
I have been wondering about this project and how to control my 4 pin pwm fans.
So after that no electricity flows through it turning the fan off.
How to connect it.
On the pcb there is a 5 12v input for the fan supply.
Pwm waves with various duty cycle are shown in the figure below.
Pwm fan controller sketch can be downloaded here.
4 wired fan control pwm control a pwm fan with arduino.
For this reason i used arduinos d6 pin pwm.
Beginner full instructions provided 24 154.
The pwm controller accepts the control signal and adjusts the duty cycle of the pwm signal according to the requirements.
Control the speed of the fan.
Getting temperature values from a digital or analog temperature sensor on an arduino is fairly simple.
I o pin 9 on the arduino board is directly connected to fan control input and by reading the state of 3 push buttons on pins 2 3 4 different pwm values are sent to the fan.
I had 5 laying around and thought mine as well give it a shot.
The blue led seen on the prototype board is just for verifying correct circuit.
The temperature and fan speed are reported through a 8 digit 7 segment display fitted on a rack mounted aluminium bar.
In the above wave forms you can see that the frequency is same but on time and off time are different two applications of pwm control using arduino is shown here.
The pc communicates with the arduino via the serial port.
It then becomes a matter of telling the fan pwm to raise or lower the speed based on the temperature.
There is a jumper for switching the power supply from arduino or the 12v input.
The system works by an application running on the pc checking the cpu temperature and checking whether to speed up or slow down the fans.
The arduino throttles the fans using pid logic and drives them through pwm.
It is efficient because the pass transistor is used as a switch.
As long as the cooling is on the red led is on when not cooling the green led is on.
An inexpensive single small pass transistor like 2n222 or bd139 can be used here.
Firstly make sure that you fan s are pwm controller you can check this by making sure that your fan connector has 4 wires.
