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Thread ID: 69280 2006-05-27 22:29:00 Fan Cool Down Timer. The_End_Of_Reality (334) Press F1
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458339 2006-05-27 22:29:00 Hey People :)

I am doing a little modding :D and I want to be able to have some of the case fans and CPU fan and possibly GFX card fan running for 5~10 mins after shutdown, Now I know this will entail some electronics (I have seen a fan cool down timer that only does 2 fans(but I would like to build one :D)) the amount of fans would vary from 4 case fans, CPU fan, PSU fan, GFX card (if possible) (total of 7) to all case fans (7), CPU, PSU and GFX card (total of 10) just to cool down the componants better :)

I know I will need to use some sort of gate system, XOR maybe, but how will I be able to get the required current?

What voltage should I use, 5V Standby?

Thanks :)
The_End_Of_Reality (334)
458340 2006-05-28 00:19:00 You can make your own. Using a thermostat and power it up externally. gum digger (6100)
458341 2006-05-28 00:24:00 True, but I want to have it on a timer, like this (www.ioss.com.tw) (if possible)

How would I power it externaly?

AND how would I get it to only turn on when the PC is turned off?
The_End_Of_Reality (334)
458342 2006-05-28 01:27:00 the simply way would be to simply use a backup battery. ie it simply powers the fans after the main power is turned off. not hard to build a charging ciruit (plenty of kits or ready made chargers) that dosn't over charge. the only catch is makeing it so the battery dosn't drain to low (ie shuts off when down to 11 volt) or use a timer (plenty of kits for those) to let it run for a few minutes. tweak'e (69)
458343 2006-05-28 04:05:00 www.thinktechie.com

try this
SurferJoe46 (51)
458344 2006-05-28 05:42:00 Joe, I saw that, but it only allows the use of 2 fans after power off :rolleyes:

(there was a link to the exact same product in my last post ;) )
The_End_Of_Reality (334)
458345 2006-05-28 06:04:00 That's why like to C/P the whole link into the post..it makes it easier to cull the repeats..but I was thinking in your favor anyway...np SurferJoe46 (51)
458346 2006-05-28 06:26:00 Oh, yes I see what you mean :)

I just like to build something rather than buying it, even if it costs more :rolleyes:
The_End_Of_Reality (334)
458347 2006-05-28 08:15:00 Why? A PC isn't anything like a turbocharged engine where you have a red hot turbo that needs lubrication until it cools down. PaulD (232)
458348 2006-05-28 08:39:00 First, I would power the main circuit off rechargeable battery/ies . This would be automatically charged via constant current from the 12V line in the computer .

To do the job correctly the circuit will have to be electronically in two parts . The first part will power the fans while the computer is running and the second part would be the timer circuit . The first part could be quite simple however .

A Opto Coupler could be used to monitor the 12V line . Once this turns off, it would trigger a one-shot long delay CMOS timer . This in turn would drive either a relay or power transistor/s (as required) which would turn on your fans for about ten minutes . This would not be a high precision timer but should be close enough for your purpose . If you understand this, who needs a nerd test, you are one!!

Now here's the good part, you could build the whole shooting match, (not counting the battery) for approximately $20-$30 .

If you want to send me a private message then I'd be happy to help you design a circuit .

BURNZEE
Burnzee (6950)
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