PWM to Analog converter circuit

Tealc · 14 Jan 2013 at 17:11

Couple of updates.

1. Dockie your converter is now on it's way to you. Hope you enjoy.

2. Firehorse contacted me asking for 3/4 boards for his build.

A standard one for CPU

One for his Scythe Mushashi dual fanned GPU cooler

And then an interesting one which will control two separate fans on the same PWM but Firehorse wants them to have different PWM to fan speed responses. The only way I could think of doing this without doing loads of experiments was to mount 2 complete circuits on a PCB.

You may have noticed that the board is a little smaller than usual and this is mainly down to not having the fan headers mounted on board and also because I rejigged the design a touch to cram a potentiometer directly on the board, rather than off to the side and actually take up less board than before. Everything works but doesn't give me masses of room for heatsinking, but that's fine as these converters are working on 1, maybe 2 fans at a time and therefore won't need a great deal of heat teansfer.

firehorse · 14 Jan 2013 at 22:42

They look great.

Look forward to receiving them

~Dockie · 15 Jan 2013 at 17:10

Thanks Tealc, it came today.

Just waiting on the AF120's now!

firehorse · 29 Jan 2013 at 23:10

Hi,

I'd thought I'd just post a few pictures.

This one is the one for the gpu.

This this the dual board with an extra wire to measure rpm of the B device, and the cpu one.

Before.

Detail of the graphics card before it is covered up. It's a tight fit.

After. It doesn't look neater but it is. There are no more wires coming out of the back.

In the picture you see the Musashi controller wrapped up in plastic to stop it touching anything else. However, after I installed it, I found out that the Musashi controller is not compatible with the gpu card output and the pwm-dc controller.

I've decided to replace the mounted Scythe Musashi fans with the equivalent Scythe fans but without the extra controller circuitry attached. That should then work fine. It also means the pci backplate won't be in the computer and neatens things up a little

Tealc · 29 Jan 2013 at 23:19

Thanks for the pictures. It's nice to see these things in use.

Tealc · 9 Feb 2013 at 13:23

And still from time to time people ask me to make these things.

This one is a Version 2 Turbo with Molex connectivity. You can see that it was originally a fan connector powered one. I just modded it this morning. Molex connectors are really expensive compared to some of the other components.

Resident · 9 Feb 2013 at 15:05

I'm still using the one you made me. I'm using it to control the fans on my H100i as the H100i's controller really doesn't like SP120PE fans.

doyll · 9 Feb 2013 at 15:27

Tealc makes good adapters.

Chrisoldinho · 9 Feb 2013 at 20:52

Tealc said:
And still from time to time people ask me to make these things.

This one is a Version 2 Turbo with Molex connectivity. You can see that it was originally a fan connector powered one. I just modded it this morning. Molex connectors are really expensive compared to some of the other components.

Astounding, really good work and cannot wait to get it connected

The Matrix · 9 Feb 2013 at 21:39

I should have one of these arrive sometime next week, just be interesting to see the difference to the Phanteks one.

The Matrix · 13 Feb 2013 at 13:23

Tealc

The PWM adapter arrived safely, it looks far better in the flesh and a lot better than the Phanteks one. Ive left it on the settings you posted it with, my push/pull PWM fans are spinning at 800rpm - 825rpm on average which is higher than the Phanteks which i think was around 725rpm on average, ive notived no obvious increase in noise at the higher fan speeds.

Mines basically the same as the above one without the molex power adapter but 3 pin PWM.

Thanks again.

Subliminal Aura · 13 Feb 2013 at 13:29

Oh man ! this is too cool to believe .... I've been looking for one for ages ?

Where do I sign, pretty please ?

doyll · 13 Feb 2013 at 14:03

Subliminal Aura said:
Oh man ! this is too cool to believe .... I've been looking for one for ages ?

Where do I sign, pretty please ?

Control yourself mate! Don't what you to have a heart attack!

Tealc does great work.
Now that I have 7 phanteks fans I might have to get one of his adapter/controllers myself.

Tealc · 14 Feb 2013 at 00:42

Subliminal Aura said:
Oh man ! this is too cool to believe .... I've been looking for one for ages ?

Where do I sign, pretty please ?

Trust.

doyll said:
Control yourself mate! Don't what you to have a heart attack!

Tealc does great work.
Now that I have 7 phanteks fans I might have to get one of his adapter/controllers myself.

Thanks mate.

I thought you were a Thermalright TY fan man?

7 might be pushing it a little far

I'd probably look to split that load across either 2 boards or at least a board with 2 circuits, something like I made for someone else to control twin GPU coolers.

doyll · 14 Feb 2013 at 01:23

I... well.. I was just given a nice black Phanteks TC14PE for my birthday. So if I want to use their new 3 PH-F140 fans I'll need something that can control them.. I'm not sure what I want to do. I do prefer real PWM fans.

Oh, the GPU adapter/splitter works beautifully. Only problem was with it running a case fan and the CPU fan socket running the other case fans the stock GPU fans sounded horrible.

I noticed the GPU cooler behind the cover was 75x240mm so took the cover off (stock fans mounted in cover) and tried strapping a couple of cheap Arctic F12 TC fans on. As crazy as it sounds slipped the temp sensors between cooler and GPU board and fans idle 600rpm and max 1350rpm with your adapter still running the case fan off of GPU PWM. Crazy thing is even with no fans plugged into GPU the GPU still show their rpm going up and down with GPU heat.

The Matrix · 14 Feb 2013 at 12:14

Subliminal Aura · 15 Feb 2013 at 11:54

Tealc said:
Trust.

Replied back to your mail - Not sure if you've received it or are busy but I can wait

Cheers

Tealc · 15 Feb 2013 at 17:17

Was out last night and in work today.

Subliminal Aura · 15 Feb 2013 at 18:47

Many thanks

.... btw one thing that I was wondering was whether or not it's possible to monitor the fan speeds of the remaining 2 channels ?

Tealc · 15 Feb 2013 at 19:01

Possible...yes....provided you run several RPM outputs.

So as well as the PWM connector you'd also have two other connectors coming off the converter for plugging into your motherboard. Bit of a spider thing going on.

or, now that I think about it...

Another alternative would be to have the RPM line connected via a multi-position switch (and I do have some) then switch manually between 1, 2 and 3 so you could at least get an idea of each individual fan is running at that particular time, but only ever one at a time.

You could also use a microcontroller and output each fan's output to the motherboard in sequence and a LED indicator next to each fan output to tell you which is reporting.

Far cheaper but along a similar thought process you could use a 4017 CMOS IC triggered by a 555 timer to count each part of the circuit, opening a transistor to act as a switch. Or use a SPST momentary switch to trigger the 4017 CMOS IC to go to it's next count. Again a LED could indicate the fan outputting.

So yes it's possible. Just a bit of a fiddle and you'd have to consider the value of going down this router, besides the fun of designing the circuit of course.

I have thought of adding LED indicators to the board for fun but again is just a thought.