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.
Arduino pwm fan controller.
I have been wondering about this project and how to control my 4 pin pwm fans.
The blue led seen on the prototype board is just for verifying correct circuit.
A low frequency pulse width modulation pwm signal whose duty cycle is varied to adjust the fan s speed is used.
The temperature and fan speed are reported through a 8 digit 7 segment display fitted on a rack mounted aluminium bar.
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 pwm controller accepts the control signal and adjusts the duty cycle of the pwm signal according to the requirements.
There is a jumper for switching the power supply from arduino or the 12v input.
Control the speed of the fan.
It is efficient because the pass transistor is used as a switch.
Firstly make sure that you fan s are pwm controller you can check this by making sure that your fan connector has 4 wires.
Getting temperature values from a digital or analog temperature sensor on an arduino is fairly simple.
The ultimate project is to control the fan based on temperature.
The pc communicates with the arduino via the serial port.
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.
It then becomes a matter of telling the fan pwm to raise or lower the speed based on the temperature.
The frequency values can be adjusted between 125 hz 8 mhz as well as a variable duty cycle.
Pwm fan controller sketch can be downloaded here.
As long as the cooling is on the red led is on when not cooling the green led is on.
Beginner full instructions provided 24 154.
The system uses a temperature sensor to control four fans that are driven by an arduino controller.
How to connect it.
Pwm waves with various duty cycle are shown in the figure below.
Many projects that use a temp sensor but never the most simple thing.
So after that no electricity flows through it turning the fan off.
On the pcb there is a 5 12v input for the fan supply.
For this reason i used arduinos d6 pin pwm.
Design schematic diagram is shown next.
I had 5 laying around and thought mine as well give it a shot.
I simply want to control a 4 wired fan or maybe several with an arduino board.
There is some information out there.
The arduino throttles the fans using pid logic and drives them through pwm.
