Fan controller with external on/off control

Steerpike · Post by **Steerpike** » Sun Mar 30, 2003 9:53 am

I have a digital doc 5 (Digidoc 5) temperature monitor and fan controller. It's great in that it monitors up to 8 temps and lets you set arbitrary temperature 'setpoints' to allow you to turn on up to 8 fans when the set temp is passed (individual setpoints per channel).

This is great, but the fan is either 'on' or 'off'. Right now, I have each fan-control output of the DigiDoc feeding into a zalman Fan Mate controller, so I can manually set the fan speed on the channel. Works great, but ... to change the fan speed, I need to open up the case (and the case innards are a jungle of wires!). Ideally, I'd like a second unit that mounts in a drive bay, that lets me speed (voltage) control, say, 4 fan speeds, on/off-controlled by the Digidoc.

There are MANY fan controllers that allow you to vary the speed of say 4 fans, but they all, as far as I can see, use their own fan power supply - none allow you to hook up an external fan power line as 'input'.

In other words - I want the digidoc to provide the 'fan on/off' control (power source), and the second unit to take this fan power source and then regulate it's voltage for speed control. Anyone know of such a device?

I've also tried the 'fanstorm' device, as an aside, and found the pwm control to be very noisy so I've given up on that route.

Post by **MikeC** » Sun Mar 30, 2003 11:47 am

Both Sunbeam and Zalman multi-channel fan controllers should let you do what youy want. They get their power feed directly from the PSU, working much like the fanmate1. Look for reviews on these soon.

dinde · Post by **dinde** » Sun Mar 30, 2003 12:02 pm

if u have more than 4 fans, this zalman rheobus can control 6http://www.zalman.co.kr/usa/product/zm-mfc1.htm

Steerpike · Post by **Steerpike** » Sun Mar 30, 2003 11:50 pm

Sorry, I think you both missed the point of my question.

The Zalman Rheobus, for example, let's you adjust the voltage supplied to a number of fans, controlled by front panel knobs. Great. BUT - what turns the fans on/off in the first place? Presumably the device itself.

What I'm looking for is something that will allow me to set the voltage supplied, but not control the on/off state of the fan itself. I want my DigiDoc5 to decide if the fan is on or off (based on it's monitoring of temperature), but I want the 'new device' to control the voltage supplied, so I can adjust the speed when it is on.

I achieve this today by hooking the output of the DigiDoc to a zalman FanMate, but it's messy having all these individual FanMates hooked up to the outputs of the DigiDoc.

Does this make sense?

Post by **MikeC** » Mon Mar 31, 2003 12:50 am

2 of the Zalman multifan controller should let you run it that way -- but what's wrong with running the DigiDoc between the fans and the multichannel voltage controller? Can't you run it that way?

Steerpike · Post by **Steerpike** » Mon Mar 31, 2003 10:53 pm

I don't seem to be explaining this well. The issue is, 'on/off' control of the fan.

The digidoc has a single power supply for all fans it controls. Thus, it has one power input, and 8 power outputs. It can't therefore sit 'between' another device and the fans.

Similarly, the zalman multifan controllers seem to have only one power input, and supply variable voltage output to 4 fans. So it can't be 'controlled' by the digidoc.

The device I'm looking for would require up to 8 separate 'input' channels - one for each fan (which I would connect to the 8 output lines of the digidoc). It would provide 8 separate 'voltage reduced' outputs, which would be connected to up to 8 fans. Thus - the digidoc would decide whether a fan should be on or off; if 'on', it would supply voltage to the fan controller. The fan controller would then allow the user to reduce the voltage provided to the fan itself.

I don't need 8 channels - 4 would be fine. The device would thus have 4 inputs, 4 outputs. It would be identical, functionally, to having 4 Zalman fanMates side by side - 4 inputs, 4 outputs.

Am I misunderstanding how the Zalman multiFan controllers work? The diagram I saw (at the URL provided) http://www.zalman.co.kr/usa/product/zm-mfc1.htm shows 4 fan outputs, but only one power input. Maybe I'm not reading the diagram correctly?

Marvin · Post by **Marvin** » Tue Apr 01, 2003 12:23 am

I think that there aren't ready products like that because most of people don't have that kind of setup.

It would be easy to make though. About four components per channel, resistor, potentiometer and two transistors. Decent pcb could be made out of stripboard. Biggest problem would be finding nice looking knobs to pots.

And of cource making holes to pots to case...

Steerpike · Post by **Steerpike** » Mon Apr 21, 2003 8:36 pm

Well I bought the Zalman ZM-MFC1 multi fan controller. Works OK (not in the manner I was hoping in my earlier posts, but I've given up on that).

But - to my dismay - the four rotary fan control knobs do NOT have an 'off' position. Thus, even on the lowest setting, the fan is still on.

Maybe some people consider that a good feature, but for me - I want to turn the fans off completely under some circumstances. Basically, I have an ultra-silent system, but once in a while I do heavy-duty video encoding, and that cranks up the CPU temperature unbelievably, so I need to crank up the fans just for this one use. But under normal use, the fans in question don't need to run at all (I have the Zalman flower heatsink, so I was able to setup a second fan pointing at the heatsink).

Oh well, the search continues.

PaqMaster · Post by **PaqMaster** » Mon Apr 21, 2003 8:49 pm

Not sure if your motherboard is supported but have you tried SpeedFan? http://www.almico.com/speedfan.php

I use it to adjust my radiator fan for my water cooling setup. I set it so it runs at about 50% (~6V) until it reaches 52C, at which point the fan hits 100%. Works great for me since it rarely gets over 52C even though my CPU is OC'd and running at 1.8Vcore. (although Folding@Home does push it up there once in a while

)

Hope that helps.

rpc180 · Post by **rpc180** » Mon Apr 21, 2003 9:45 pm

um ... I don't know if it has all of your expectations, but the Sunbean rheobus has an off posistion (which allows it to be used with their CCFLs).

trpltongue · Post by **trpltongue** » Tue Feb 03, 2004 11:38 am

Steerpike,

I am looking for the exact same thing as you. Here's what I think you can do. Plug a molex connector into the digidoc power input. Take fan output 1 of the digidoc5 and plug that into the power input of the sunbeam rheobus. Set the digidoc5 to turn on fan output 1 above your set temperature. Now whenever the temp gets above your set temp, the digidoc will supply power to the sunbeam and you can control the sunbeam from outside of the case. Problem solved!

Russ

Bluefront · Post by **Bluefront** » Tue Feb 03, 2004 4:45 pm

I'm using a DD5 also.....I know exactly what you mean. Have you considered using the DD5 to turn on thermally controlled fans? This works pretty well. A fan could turn on at say 40c.....from that point on it's speed would be controlled by it's own sensor.

As an alternative solution......There is a newer version of the DD5, called a DD5 Plus. It has USB and Firewire ports in place of the small fan. The on/off points for the fans are better controlled, and at least one review claimed the unit would adjust fan speeds, as well as turn them on/off. I'm not certain about that though.

silvervarg · Post by **silvervarg** » Wed Feb 04, 2004 7:12 am

What about a DIY solution?
Just put a potentiometer on each fans + wire (red) and drill a hole in the chassi or front plate to mount the potentiometers there.
A quite check and I see that a set of 5*470ohm potentiometers is about $3 here.
These pots can only take 0.2W, so you might need to get more powerfull ones or put a resistor in series with them or have the fanmates as well (before the pot) to reduce the power a bit for your high power fans.

With this solution you will be able to turn fan speed voltage down to almost 0volts, so you need to mark lowest setting for each fan.