Automatic Fan Control based on Water temps or CPU Temp?

So I'm planning on building an automatic fan controller that will either be controlled by speedfan or the temps from a k-type thermocouple plugged into my res. Possibly learning how to program a basic PIC microcontroller that would change fan speed based on delta of ambient to cpu block outlet. What would you guys go with?

The Speedfan version would be the easiest as I'd just use a emitter-follower circuit. My issue is if my asus would output a linear voltage if plugged into a 3 pin instead of 4 pin since it's supposed to be PWM. Don't want to deal with a PWM circuit as I want it to be quiet and I'm running all Gentle Typhoons so the amount of heat dissipated by the op-amp would be minimal. I'm just afraid of startup current for the motherboard header which is the reason I don't just plug all the fans directly into the fan header.

Based on just water temps I have the issue with ambient changing (summer vs winter) which will cause the fans to run faster during idle.

Wish I knew how to integrate a circuit with windows program that could control the fan speeds based on ambient temps, water temps, cpu temps, and cpu load. Then I'd do some fancy fan controls that would ramp up and down at slow speeds to maintain a good temp.

CPU temps changes right away, so the fans can ramp up/down really odd. Water temps take a while to rise, so water temps are better. But your chip temps could climb a bit before the fans come into play, and it takes a bit for the fans to cool the water down.

So your choice. Umm Speenfan is soo far behind the power curve unless it works good with your mobo.

DumpALump said:

So I'm planning on building an automatic fan controller that will either be controlled by speedfan or the temps from a k-type thermocouple plugged into my res. Possibly learning how to program a basic PIC microcontroller that would change fan speed based on delta of ambient to cpu block outlet. What would you guys go with?

The Speedfan version would be the easiest as I'd just use a emitter-follower circuit. My issue is if my asus would output a linear voltage if plugged into a 3 pin instead of 4 pin since it's supposed to be PWM. Don't want to deal with a PWM circuit as I want it to be quiet and I'm running all Gentle Typhoons so the amount of heat dissipated by the op-amp would be minimal. I'm just afraid of startup current for the motherboard header which is the reason I don't just plug all the fans directly into the fan header.

Based on just water temps I have the issue with ambient changing (summer vs winter) which will cause the fans to run faster during idle.

Wish I knew how to integrate a circuit with windows program that could control the fan speeds based on ambient temps, water temps, cpu temps, and cpu load. Then I'd do some fancy fan controls that would ramp up and down at slow speeds to maintain a good temp.

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Sounds like you a going to build your own speed control circuit, which is something that I would never do. However, I suspect that there is some real wisdom and insight in your post that would benefit all the non-DIYers like myself. Any chance you could "distill" down your concerns and ideas into a "what to look for in a fan controller and how to set it up in your system," guide. Heck, it could even become a stickie.

what you have to do is this.
decide which of the 2 realms you fit in.
in either case you have to start with a timed profile in which you tailor the initial startup and running until normalization and then let the program take over depending on .

1 do you have enough previous data to use water temps for your rig which most people dont and the hardware sensor requirement is a whole nother animal alltogether
or
use the cpu temp which has a wider range and could take a lot more programming and trial and error but has the sensors already in place and ultimately is your begining point for your equation anyways and the whole idea to cool.

you will see that i harp on people especially new people about how temps mean nothing and its all about having the best oc to noise ration and remaining stable.
this on the other-hand what you are trying to do is exactly what someone should be trying to use temps for.

its not about making your computer as cool as possible its about creating a profile that works and satisfies noise to stability .

either way you will have to build a pre programmed time into the startup just like your mobo post that runs everything at max or near until enough data has been fed to your controller to tell it there needs to be a change which in the end is where all your trial and error goes to

Conumdrum said:

CPU temps changes right away, so the fans can ramp up/down really odd. Water temps take a while to rise, so water temps are better. But your chip temps could climb a bit before the fans come into play, and it takes a bit for the fans to cool the water down.

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Yep, that's my issue. I think I'll just go with water temps. I'll figure out the delta at load, then use that to figure out the temperature at which to start ramping up the fans 5-10C before hand.

x509 said:

Any chance you could "distill" down your concerns and ideas into a "what to look for in a fan controller and how to set it up in your system," guide. Heck, it could even become a stickie.

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If you're looking for a good non-DIY solution, then I'd hit up the Aquaero. Pretty sweet, though costly. I'd buy it if I wasn't being cheap and wanting to tinker with electronics. Version 5 is supposed to be out soon and it's looking pretty awesome.

Watch it in Action on Youtube

Alternatives:
Alphacool Heatmaster - Forgot if I'm allowed to link to other forums. Just do a search. I'd say price would be similar to the aquaero either way.
mCubed T-balancer

Like Thorilan said, its all about scaling fan speeds with cpu temps and stability. Linear vs PWM - PWM more efficient, but can be at the cost of noise. Linear - Puts out heat and is inefficient. Depending on fans though it might not matter much. I'm just trying to get the fans to slowly scale with temps, but also not run faster than they need to be (5v 1850GTs are pretty quiet).

Like Conumdrum said, it takes a while for the water temps to go down, and I'm also concerned with ambient temps. So say you had a hard gaming session, but it takes 5 minutes (no idea on actual time) to cool the water back down then your fans would be running a lot faster than they need to be since the heat source has now been lowered back to idle. Say it's 100F (~38C) then it'll take longer for that water to cool than if it was 60F (~15.5C). Also if I were to set my ramp up temps to start too low then on hotter days it would run faster at idle or while doing simple tasks.

Quick fan speed changes are annoying as it'd go full bore - slow speed - full bore - slow speed, when doing things.

Reason I don't want to go with a basic fan controller is you have to flip the switch or turn the knob yourself. I don't always plan in advance when I'm going to do something. It'd just be a pain (i'm lazy) to have to do that.

PS not one for writing guides, but hope this answers some of your curiosities

Excellent post, thanks for the link to Aquaducts site. I am putting together a folding system, and have been doing some research on water cooling it. Like yourself, I would rather have (ideally) a unit controlled seperately from the computer itself, but able to integrate to it via software if desired, that will work with my setup. I have a EVGA x58 4 way classified and got a great deal on 4 EVGA GTX295 Hydro video cards. I ended up going lower end on the CPU i7 950 and 6 gig of Corsair Dominator memory, but still plan on OCing it a bit. I am building my cooling system myself, have found 2 heater cores from NAPA that are 9.5 x 9.5 x 2.5" with 5/8" outlets that are copper/brass (no plastic or Aluminum) designed for a Dodge panel van, and a total of 8 Ultra Kaze 120mm 3000 rpm fans that I would like to control. I have been doing a little reading so far, and it sounds like PWM is not the best way to go to control fans if noise and fan longevity are important, is this basically true? I checked out the Aquaero Pro and XT, both look nice, but as you said, not inexpensive.

Of course, because I just stumbled across this posting, I had earlier today ordered 2 KAZE Master Ace "5.25" Bay Fan Controller - Black (KM02-BK) from Amazon, along with 2 more fans to bring them up to a total of 4 per radiator (they should fit perfectly, I just need to make a shroud), so I guess at this point I am pretty much stuck with manual because their site says I can't modify or change the order. What would you recommend to control the rest of the system, such as the water pump speed, etc? I suppose I could return them, and start over. How difficult do you think it would be to DIY it like you are planning on doing, and do you need a EE degree to pull it off? I'll be watching this thread as you progress. Thanks for the info!

alha said:

Excellent post, thanks for the link to Aquaducts site. I am putting together a folding system, and have been doing some research on water cooling it. Like yourself, I would rather have (ideally) a unit controlled seperately from the computer itself, but able to integrate to it via software if desired, that will work with my setup. I have a EVGA x58 4 way classified and got a great deal on 4 EVGA GTX295 Hydro video cards. I ended up going lower end on the CPU i7 950 and 6 gig of Corsair Dominator memory, but still plan on OCing it a bit. I am building my cooling system myself, have found 2 heater cores from NAPA that are 9.5 x 9.5 x 2.5" with 5/8" outlets that are copper/brass (no plastic or Aluminum) designed for a Dodge panel van, and a total of 8 Ultra Kaze 120mm 3000 rpm fans that I would like to control. I have been doing a little reading so far, and it sounds like PWM is not the best way to go to control fans if noise and fan longevity are important, is this basically true? I checked out the Aquaero Pro and XT, both look nice, but as you said, not inexpensive.

Of course, because I just stumbled across this posting, I had earlier today ordered 2 KAZE Master Ace "5.25" Bay Fan Controller - Black (KM02-BK) from Amazon, along with 2 more fans to bring them up to a total of 4 per radiator (they should fit perfectly, I just need to make a shroud), so I guess at this point I am pretty much stuck with manual because their site says I can't modify or change the order. What would you recommend to control the rest of the system, such as the water pump speed, etc? I suppose I could return them, and start over. How difficult do you think it would be to DIY it like you are planning on doing, and do you need a EE degree to pull it off? I'll be watching this thread as you progress. Thanks for the info!

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Good ol heatercores Used to have one back in 2002 I believe, worked pretty well. PWM isn't bad, and it is a lot easier to deal with than linear. A lot of it depends on how well your fan deals with it. You might hear ticking or you might not.

For the pump, I just secure it to the bottom of the case with no control. Since my P183 is pretty sturdy, the main noise comes from my fans. If there was an issue, I'd try to suspend the pump to reduce the amount of vibrations transferred to the case.The DIY I'm doing is pretty simple, doesn't require an EE degree (I don't have one and just randomly decided to start reading books and researching electronics), but will still cost about $20 depending on what you have around. For a real circuit board it'd cost more. Initial fixed costs are high, but every circuit built afterward is cheaper.

The 950 I wouldn't say is low end. I'm cheap, I always try to go bang for the buck after overclocking or mods. Had a I5 750 recently till my new 2500k sandy. Tons of people use manual fan control and continue to suggest them. Though if I were you, I'd even just get an automatic fan control with thermistor (that scales) and tape it to the side of the waterblock. Then I'd test to see what the thermistor says at full load so you have an idea of where to place the max fan speed.