Many projects that use a temp sensor but never the most simple thing.
Arduino pwm fan controller.
Temperature based fan speed control monitoring with arduino.
There is a jumper for switching the power supply from arduino or the 12v input.
I have been wondering about this project and how to control my 4 pin pwm fans.
Firstly make sure that you fan s are pwm controller you can check this by making sure that your fan connector has 4 wires.
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.
Getting temperature values from a digital or analog temperature sensor on an arduino is fairly simple.
Beginner full instructions provided 24 154.
As long as the cooling is on the red led is on when not cooling the green led is on.
The pc communicates with the arduino via the serial port.
Design schematic diagram is shown next.
For this reason i used arduinos d6 pin pwm.
I had 5 laying around and thought mine as well give it a shot.
Control the speed of the fan.
How to connect it.
The system uses a temperature sensor to control four fans that are driven by an arduino controller.
4 wired fan control pwm control a pwm fan with arduino.
The blue led seen on the prototype board is just for verifying correct circuit.
There is some information out there.
The frequency values can be adjusted between 125 hz 8 mhz as well as a variable duty cycle.
It is efficient because the pass transistor is used as a switch.
The arduino throttles the fans using pid logic and drives them through pwm.
On the pcb there is a 5 12v input for the fan supply.
So after that no electricity flows through it turning the fan off.
The ultimate project is to control the fan based on temperature.
Pwm fan controller sketch can be downloaded here.
A low frequency pulse width modulation pwm signal whose duty cycle is varied to adjust the fan s speed is used.
The pwm controller accepts the control signal and adjusts the duty cycle of the pwm signal according to the requirements.
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.
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.
An inexpensive single small pass transistor like 2n222 or bd139 can be used here.
