Make your own PWM controller

jamesm · Post by **jamesm** » Fri Jul 15, 2005 8:47 am

http://casemods.pointofnoreturn.org/pwm/

really helpful walkthrough for those who like to tinker with things. I can't find the 555 IC at my local radioshack though.

liquid_celica · Post by **liquid_celica** » Fri Jul 15, 2005 9:25 am

its just so much easier to buy a fanmate 2 for like 2 bucks.

jamesm · Post by **jamesm** » Fri Jul 15, 2005 10:26 am

Correct me if I am wrong, but the fan mate 2 isn't a PWM controller.

frankgehry · Post by **frankgehry** » Fri Jul 15, 2005 10:42 am

J,

I guess not everyone is interested in building a fan controller, but I have been experimenting for a while. I am using a microchip fan contoller IC that makes it relatively simple to get started. The parts for these are not very expensive if you order from www.digikey.com. Here is my project so far.

http://forums.silentpcreview.com/viewtopic.php?t=23300

www.microchip.com has a wealth of information in their fan management section.

Mike_Metro · Post by **Mike_Metro** » Fri Jul 15, 2005 10:57 am

This is a great site I found (maybe here...I can't remember) a little while ago. Lots of schematics for fan controllers (PWM and others).

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

lenny · Post by **lenny** » Fri Jul 15, 2005 11:25 am

There's also a thread by the user fancontrol about building a custom fan controller.

One thing that I find lacking in fan controllers is the ability to measure outside temperature, and adjust the fan speed accordingly.

sundevil_1997 · Post by **sundevil_1997** » Fri Jul 15, 2005 12:08 pm

Pretty comprehensive info, though a bit out of my league. I added a link to it in the Build your own controller sticky post above. It's nice to have some variety.

jamesm · Post by **jamesm** » Fri Jul 15, 2005 1:08 pm

Frank, was yours a PWM controller, or just a thermal management fan controller?

This looks really interesting. If I ever find the time to try one of these out, this would make a good weekend project.

frankgehry · Post by **frankgehry** » Sat Jul 16, 2005 9:24 am

j,

Yes its a pwm controller.

Its uses a small voltage range as determined by the thermistor to drive a fan with pwm. It takes a 5v input for the control section and a 12v input for the fan drive section that is perfect for using with a molex connector. One pair of resistors determine the min speed and another pair sets the speed temperature curve. - FG

sthayashi · Post by **sthayashi** » Sun Jul 17, 2005 1:04 pm

Jamesm, that site had a lot of misinformation on there regarding Linear Power control.

And if you can't find the LM555 chip at Radio Shack, look for the LM556. It's basically 2 LM555s in one.

sundevil_1997 · Post by **sundevil_1997** » Mon Jul 18, 2005 10:12 am

sthayashi wrote:Jamesm, that site had a lot of misinformation on there regarding Linear Power control.

You mean in regards to it's "PWM vs. Linear" comparison? The site is good otherwise, right? as far as building a PWM controller?

aowen512 · Post by **aowen512** » Mon Jul 18, 2005 5:52 pm

some may be pwm and some just may be voltage regulation either switches or reostats but here are a few sites you might want to check out

http://www.overclockers.com/tips1127/index02.asp
http://www.fanbus.com/
http://dbserv.maxim-ic.com/appnotes.cfm ... umber/1784
http://casemods.pointofnoreturn.org/vre ... -full.html
http://www.pcmoddingmy.com/content.php?article.83
http://www.7volts.com/rheostats.htm
http://www.cpemma.co.uk/sdiodes.html
http://www.virtual-hideout.net/guides/m ... dex3.shtml
http://www.virtual-hideout.net/guides/fanbus/

hope some of these help, and remember to use the base website like 7volts.com to look at too and not just the page that i listed

good luck!

sthayashi · Post by **sthayashi** » Mon Jul 18, 2005 6:54 pm

sundevil_1997 wrote:
sthayashi wrote:Jamesm, that site had a lot of misinformation on there regarding Linear Power control.
You mean in regards to it's "PWM vs. Linear" comparison? The site is good otherwise, right? as far as building a PWM controller?

I think so. I don't really play around much with the LM555 chip much, but I do know that you can use it for timing control. Every single con listed under Linear control is either misinformed or blown out of proportion.

If you hadn't guessed yet, I'm rather biased against PWM control. Anyways, one thing I'd be wary about when assembling a PWM controller is utilizing a frequency that is within human audible range. I'd advocate using something around 20 KHz. But this is coming more from theory than experience.