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Topic: Temperature based fan controller (Read 1 time) previous topic - next topic

No1Daemon

Hi all

I just bought a variable regulated dc power supply for testing purposes and the fan is very noisy. I would like to use the arduino platform to build a fan controller for it so if I am drawing a small load the fan is either off or at a lower speed until the temperature requires a faster rpm.

Would any of the existing pc fan controller circuits etc already made suit my purposes?
It will probably be pid control I assume from what I have read so far.

If anyone has a project suggestion for me or could point me to a good post on the subject please let me know.

Thanks
Steve

Coding Badly


Tough to give any help.  You have not provided any details about the fan.

No1Daemon

Sorry about that. It seems to be a standard 12v case fan. Will measure it shortly but I think its a standard 60 or 80 mm.
there is just the one 12v connector coming off the board. There is also a thermistor I am guessing attached to the heatsink but I cannot read what type it is due to the positioning.

As the fan comes on full time I am guessing that the circuit for reading the temperature etc is not working and therefore I should be able to attach the Arduino circuit to the existing 12v connector and have it powered constantly.

I am guessing I could just get a 1 wire device like the ds18b20 and add either a voltage divider or a voltage regulator to provide 5v to the arduino and the rest will be done in software.

Coding Badly


Do you plan to make a variable speed controller or an on/off controller?

If you believe the temperature sensor is not working, why don't you exchange it?

No1Daemon

I am not sure what the circuit is, I think it is pic based that drives the temperature controller.
It seems to be a common fault because the person who suggested I buy one and recommended it to me has the same thing and has devised his own board, I wanted to make something non pic based though because I never had much luck with those microcontrollers.
I understand Arduino a little more.

I was planning on making it variable based on the load if possible.

Just reading up on PID control but I am nowhere near getting my head around it yet.

Coding Badly


Some reading material that may help...

http://www.thebox.myzen.co.uk/Tutorial/PWM.html

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1242351267
http://arduino.cc/forum/index.php?topic=67380.0
http://arduino.cc/forum/index.php?topic=69890.0

Quote
Just reading up on PID control but I am nowhere near getting my head around it yet.


Given the constraints (very fast acting control point; slowly changing process variable) I suspect you can get good results with a very basic algorithm: Temperature a bit too high?  Speed up the fan just a bit.  Temperature way too high?  Set the fan speed to maximum.  Temperature going down?  Slow down the fan just a bit.  Temperature normal?  Stop the fan.  Delay for a short time.  Repeat.

If you really want to get fancy, measure the power output (or input) and try your hand at predictive control.

No1Daemon

Thank you. Some good stuff there I never found when I was searching.

Coding Badly


Include "grumpy_mike" in your search.

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