Heat controlled fan. (High temp = fast fan) vice versa

[zac-uk]

Hello there, im an AS Electronics student and ive been researching in index magazines for weeks now in lesson and havent found a single useful piece of information to help me with my project.

Im aiming to create a temperature controlled fan. The specification is that i want several 'motors' (we dont have fans at college) to be connected to a unit with some sort of temperature controller and other device. When the heat is over a certain amount, i want the motors to get a full voltage supply (cooling the system),when the heat is low, limit the voltage to them so they are quiet.

It suposd to be for a computer, to control fans.

I may have limited resources at college, can anyone suggest a simple way of doing this? I may also require an LCD display to show temperature.

Thanks a lot, this will really help me get going, weve got an inspection due in a few days and i have been struggling to get going for a while now, and ive deiced to ask for some professional help.


Thank you, thank you and thanks again.

Zac Robinson

 

[stevez]

I'll help you get started. You'll need to have something to measure temperature and provide a signal that can be compared to a reference or possibly a setpoint. The result of that comparison would be the error - and that error would then provide an indication of fan speed - if temp signal and reference are equal - no error - no voltage to fan - big error - higher voltage to fan.

I'd do it in blocks so you understand what you are doing - and you can explain it. Proportional control might be good to research.

You'll learn quickly that many of us will help you do your work but we won't do it for you.

Good luck.

 

[johankj]

To control the whole project: A Micro-controller (MCU). Select an MCU that has analogue to digital converter (ADC), Pulse witdth modulation (PWM), and at least another 6 digital I/O lines.

To read the temperature: A temperature sensor and then use the ADC(Inside the MCU) to read the temperature.

To control the fan: The PWM will control the fan speed for you, in up to 255 steps, from off to max. However, a DC-fan is probably required here.

To write to the LCD: You can use the MCU to do that.

All you need in addition, is a programmer to program the MCU. This depends on your choice of MCU...

 

[HiTech]

This was a very easy search using my browser:

READ THIS FIRST: **broken link removed**


http://www.redcircuits.com/Page109.htm

http://www.almico.com/speedfan.php

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http://www.cpemma.co.uk/thermal.html

http://www.heatsink-guide.com/content.php?content=control.shtml

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http://microblog.routed.net/2007/06/27/how-to-make-a-temperature-based-fan-controller-without-a-thermistor/

**broken link removed**;