Circumvent MOBO for 4-pin fan control

[vinno97]

Hi everyone!

I have an interesting problem about controlling my fans without using the fan controller on my motherboard. I hope I'm in the right section for this and I'm very curious to hear what you guys think of my problem.

Problem:
I recently bought an HP 600 G1 mini as a home server and flashed it with Proxmox. Problem is that there are no drivers to control HP's on-board fan controller from Linux, resulting in the fan being 100% all the time (BIOS settings have no effect on actual fan speed). Now the system is most often idling and still makes an immense noise with the fan at this speed.

Possible solutions?
What are my options to control or reduce the fan speed? I don't mind some jankyness, but I do want it to work properly. Also, I went for this HP thin client precisely because it was a cheap solution. Can't be spending €80 on a fan solution. I currently have these three options in my head, but none of them seem like proper solutions

• Buy a USB fan controller
  • Pro: can control my fans from inside linux (using fancontrol)
  • Con: I can only find big controllers for enthousiasts for 50+ euros. I
    • There must be something cheaper, right?
• Solder a resistor or potentiometer in series with the fan to reduce the fan speed to a workable speed
  • Pro: more quiet, longer lifespan, cheap
  • Con: doesn't adapt to temperature
• Solder a thermal resistor in series with the fan and glue it to the heatsink
  • Pro: adapts to temperature
  • Con: Probably very difficult to tune and I expect many unforeseen issues with this.
• Write my own driver
  • Pro: No extra hardware and will be doing the community a service
  • Con: No way that I'm reverse engineering this and writing a kernel for it. I'm an adequate programmer, but there are limits to my madness.

 

What do you guys think. Is there a reasonable solution to my problem?

Thanks!

[IkeaGnome]

1 hour ago, vinno97 said:

Solder a resistor or potentiometer in series with the fan to reduce the fan speed to a workable speed

• Pro: more quiet, longer lifespan, cheap
• Con: doesn't adapt to temperature

 

What about a Noctua NA-FC1? 

[ImorallySourcedElectrons]

Some industrial PID controllers also support PWM output, so you could strap in one of those and get a temperature out of the I2C bus on the motherboard, but that'll probably end up costing more than the USB fan controllers.

[RandleMcmurphy]

It says in the manual that the fans are under automatic control. see page 73, 

Quote

Thermal Fan idle mode—This bar graph controls the minimum permitted fan speed.
NOTE: This setting only changes the minimum fan speed. The fans are still automatically
controlled.

 

...this should be independent of the operation system?

 

 

[HanZie82]

Or go the DIY route.
Get yourself a Arduino nano and a temp probe for it.
Then you should be able to output a PWM signal the fans can use to change speed.
Might even be able to use the speed pin to report fan-speeds too.

It does however  (if not already done and shared) mean a lot of work and programming.

[vinno97]

Firstly, sorry for the slow response. Christmas got in the way

 

On 12/26/2022 at 5:45 AM, RandleMcmurphy said:

It says in the manual that the fans are under automatic control. see page 73, 

 

...this should be independent of the operation system?

 

 

So apparently this setting does work. I just didn't notice it because the fan is still way louder than I'd like. I already had it set to the minimum, but it is still very loud. Setting it to high (or even one tick higher than the minimum), did increase the airflow from it.

 

Listening, and looking, to the fan, now, it does sound like it's not spinning that fast. I suspect the bearings of the fan are just worn out, causing it to sound horrible even during it's low idle.

 

Might still see if using an arduino (have one laying around) allows me to quieten it a bit, but that would mainly be to satisfy my curiosity then.

 

Thanks guys!

 

[Heats with Nvidia]

If you have any interest in that, you can also try the analog route and build your own fan controller. Especially with comparators like the LM339/LM2901 its failry easy to create a voltage controllable PWM source. You could even abuse one of the comparators as an amplifier for whatever you use as the temperature sensor. If you can live without temperature control, there should be enough schematics out there, that use an NE555.

 

The material cost of this route is extremely low, but it might take a while. Its also a pretty good project to learn about the analog side of things.