FEATURED Building PWM Controller for 4 wires PWM fan

[bing]

Hey Brutal, I don't have any problem with that ! Of course I wouldn't mind if someday you've made enough bucks and buy me the monster fan like yours as a gift he..he...j/k.

Seriously, do it, believe your could have quite plenty of customers, looking at the posts by fan's fanatic out there. Prolly our in house fan fanatic like Mudd will came out as the 1st one.

 

[LennyRhys]

Hi guys,

Great thread! I'm planning to build this PWM circuit for one of these fans, but my first hurdle to overcome is getting one of the fans in the first place

I live in the UK, and the fans cost equivalent to $75 EACH here (roughly $100 with shipping), which is just too much, even for such an amazing fan.

I will keep you all posted regarding my progress and I will post picture and video updates if I manage to get one of the fans and the PWM circuit up and running!

 

[Bobnova]

The basic PWM signal should be fairly similar for all PWM fans, as they all have to work (or should, at least) with motherboard PWM controllers and such.
Which means you can use a stock intel/amd cpu heatsink fan for testing.

 

[I.M.O.G.]

Cool Lenny, keep us posted. If you want to write an article, or upload your videos to the overclockers.com youtube channel, just send an email to matt at overclockers.com and I'll help out.

 

[m0r7if3r]

The basic PWM signal should be fairly similar for all PWM fans, as they all have to work (or should, at least) with motherboard PWM controllers and such.
Which means you can use a stock intel/amd cpu heatsink fan for testing.

I think there's some anomaly with this one to do with 16khz vs 25khz signals...but I could be wrong, just be careful when you build that you use the appropriate caps.

 

[LennyRhys]

I've already sourced the parts and will try to have them all by the end of the week... I have plenty generic PWM fans at home; the real problem is getting the San Ace beast fans from the US to the UK (I will not pay £100/$150+ for two fans LOL).

just be careful when you build that you use the appropriate caps.

I notice that bing's circuit diagram shows C1, C2 and C4 as non-polarized caps whereas C3 is polarized...is this important?

 

[bing]

Hi guys,

Great thread! I'm planning to build this PWM circuit for one of these fans, but my first hurdle to overcome is getting one of the fans in the first place

I live in the UK, and the fans cost equivalent to $75 EACH here (roughly $100 with shipping), which is just too much, even for such an amazing fan.

I will keep you all posted regarding my progress and I will post picture and video updates if I manage to get one of the fans and the PWM circuit up and running!

Hey LennyRhys,

Welcome to OcF !

Great to hear that, looking into to see your work.

I think there's some anomaly with this one to do with 16khz vs 25khz signals...but I could be wrong, just be careful when you build that you use the appropriate caps.

I notice that bing's circuit diagram shows C1, C2 and C4 as non-polarized caps whereas C3 is polarized...is this important?

The 25Khz is the frequency standard, that 16Khz was just an optional for that SanyoDenki beast fan since its stated to use that freq, but apparently 25Khz is working fine, so just ignore that, use 470pF for C1.

Yes, C1,C2 and C4 are non-polarized caps, just any ordinary small cap will be fine. Also I don't think you can easily find a polarized cap for these small value caps, while C3 most of them are polarized.

These components are usually easy to find.

 

[LennyRhys]

Thanks for confirming bing, and thanks for the welcome - glad to be a part of the OC community!

Special thanks to I.M.O.G. for helping me get the fans; I might have them by the end of next week, and I will definitely have the circuit built before then.

 

[LennyRhys]

OK here's the first update - I went to the local components specialist and managed to get everything except the main IC (which they say is "discontinued") so I ordered five of them from ebay and hope to have them later in the week.

Question for bing (or anybody else who knows): the 555 and 556 have - evidently - been replaced by newer ICs, 7555 and 7556 respectively, and they are supposed to have pin-for-pin interchangeability but they run on a fraction of the power. Would it be possible to use a 7556 in this circuit instead of a 556, or would resistor/cap values have to change?

Anyway here's what I got; I had no idea specifically what type of component I was buying, only the rating (1KR or 680pF etc.) so bought the prettiest and most robust looking ones I could find in the catalogue

All I need now is the IC and I'll be rocking with some PWM fans! (Special prize to anybody who can tell the difference between the 1K and 10K resistors lol...)

 

[m0r7if3r]

Question for bing (or anybody else who knows): the 555 and 556 have - evidently - been replaced by newer ICs, 7555 and 7556 respectively, and they are supposed to have pin-for-pin interchangeability but they run on a fraction of the power. Would it be possible to use a 7556 in this circuit instead of a 556, or would resistor/cap values have to change?

should be cmos 555/556 vs older one iirc, so no, there would be no difference.

All I need now is the IC and I'll be rocking with some PWM fans! (Special prize to anybody who can tell the difference between the 1K and 10K resistors lol...)

1k is brown, black, black, brown, 10k is brown, black, black, red. Can't see the pic well enough to tell you which is which.

 

[bing]

Question for bing (or anybody else who knows): the 555 and 556 have - evidently - been replaced by newer ICs, 7555 and 7556 respectively, and they are supposed to have pin-for-pin interchangeability but they run on a fraction of the power. Would it be possible to use a 7556 in this circuit instead of a 556, or would resistor/cap values have to change?

7555 or 7556 is fine for this circuit, just a suggestion, if the price is cheap, consider to buy few more as spare since cmos based chip can be easily toasted by static electricity.

 

[bing]

UPDATE !

For those with the 2-98% controller but want a 0% and 100% duty cycle feature, you can mod it with an additional 3 poles switch and a resistor to have a full 0 to 100% range, but in 3 regions -> 0% , 2-98% and 100% with this below pic

View attachment 88561

If you don't have that 100 Ohm resistor available, you can replace it with any resistor with the resistance above 100, about hundreds of ohm is ok.

 

[Seebs]

Hey bing...
I'm thinking this PWM controller would be a good little weekend project for me this holiday season; and a good way of gaining full control over my delta fan (it's on the PWM header of the mobo right now, but I'd like to be able to control speed better)

I was looking at your diagram for the 0% to 100% circuit on page one and see that C5 is a polarized cap at 47uF and 10V...
Am I safe to assume that the other caps are not polarized and at 10V as well?
Would there be any benefit from getting caps other than the regular ceramic ones?
On the Pot... Will any run of the mill linear pot with the 10K ohms rating do? Or should I look for something in particular?

Thanks
Sebastian

 

[bing]

Hey bing...
I'm thinking this PWM controller would be a good little weekend project for me this holiday season; and a good way of gaining full control over my delta fan (it's on the PWM header of the mobo right now, but I'd like to be able to control speed better)

I was looking at your diagram for the 0% to 100% circuit on page one and see that C5 is a polarized cap at 47uF and 10V...
Am I safe to assume that the other caps are not polarized and at 10V as well?
Would there be any benefit from getting caps other than the regular ceramic ones?
On the Pot... Will any run of the mill linear pot with the 10K ohms rating do? Or should I look for something in particular?

Thanks
Sebastian

Great, another participant jumps in !

Yes, that C5 is polarized cap, as you can see at it's symbol compared to other caps, also for common cap that is easily to find, 99% chance you will get a polarized one rather than non polar cap.

With this cap's size and a thru hole component (meaning component with legs), it is unlikely you will find a non polar cap, though they exist but its quite rare and most of them if non polar is smd version (surface mount cap), which is not a requirement in this circuit. Anyway, should you found a non polar version, its fine too, but I doubt it since they're much2 more expensive than the polar type.

Value wise, even its 47uF 10 Volt, any cap above 47 uF (not too large) and working voltage minimum or above 10 V will work fine too, like a 100uF 16 volt cap is ok too.

About the potentiometer, as long they're 10K and linear version, it should work, and that military pot style of yours definitely will add up the "bling" factor , really curious how it looks, if you had a chance, please post the pic of that pot.

 

[Seebs]

Thanks bing... I hope to have the parts and start work on this in a week or so... Gotta pay rent and bills first...

So let me see if I understood you correctly...
On the caps:
- I may be misunderstanding you... Are you saying C1 through C4 could be polarized as well? Or do I have to get non-polarized? I ask because you say that finding non-polarized caps would be more of a challenge, but you do list them on the diagram as non-polarized.

On the Pot:
- What "military" style pot are you referring to?

thanks
Sebastian

 

[bing]

Thanks bing... I hope to have the parts and start work on this in a week or so... Gotta pay rent and bills first...

So let me see if I understood you correctly...
On the caps:
- I may be misunderstanding you... Are you saying C1 through C4 could be polarized as well? Or do I have to get non-polarized? I ask because you say that finding non-polarized caps would be more of a challenge, but you do list them on the diagram as non-polarized.

On the Pot:
- What "military" style pot are you referring to?

thanks
Sebastian

C1 to C4 are non polar, you should not worry about this and their voltage rating since most of them are way far above 10 volt for thru hole component and 99.99% you will find they're all non polar type, also you might get the 50 volt rated cap or above, so its safe. These are easy to find common cap and any types like ceramic, polyester etc will fine too.

Forget bout the military pot , I misread you, just any pot with 100 K value , linear version will work.

 

[LennyRhys]

OK I grew impatient waiting for my 556 ICs to arrive, so I took another (unnecessary but wholly rewarding) trip to the component shop and picked up four NE555 ICs.

I put this together very quickly tonight. It works fine, but not without glitches - sometimes when I pick up the pot to turn it, the fan just speeds up; and sometimes when I turn the pot all the way up, the fan stays at the lowest speed. It depends on the orientation of the pot...I'm thinking maybe a bad solder joint/connection.

Anyway I'll put a video together tomorrow (nearly 1am here and I need my bed!); for now, here are a couple of pics of the circuit and the fan from my--now redundant--Dark Knight:

 

[bing]

Hey LennyRhys,

Congratulation, it nice to hear it just works right from the 1st time you powered that circuit.

Btw, just curious, how much that ne555 cost you there ?

I put this together very quickly tonight. It works fine, but not without glitches - sometimes when I pick up the pot to turn it, the fan just speeds up; and sometimes when I turn the pot all the way up, the fan stays at the lowest speed. It depends on the orientation of the pot...I'm thinking maybe a bad solder joint/connection.

Although I can't see clearly the solder joins at the pot's pins, but from the 2nd pic, you're using stranded wires instead of solid one for the breadboard wires connections.

Suggesting to replace those stranded wires with the solid one, from my experience, the cable for telephone installation is the best for this job, they're solid and stiff enough to work with when inserting to the breadboard's holes, also the wire's diameter fits very well.

For examples, these are the old shots of my board works at other circuits, watch at those solid jumper wires :

If the solder joins at the pot is ok, there is a possibility that it's wire connection at the board is loose, because the holes might be not holding the stranded wires firmly and making poor contact points.

Thanks for sharing, can't wait to see your fans in action, and if you have more than one PWM fans, you could try hook them up to see this circuit in action controlling multiple fans.

 

[LennyRhys]

Hey bing,

yeah my brother supervised the process and helped me with the components (he's an electronic engineer ) and he told me that these things never work first time round!

He also said I should get single core wire, so as per your recommendation I will use telephone cable next time!

NE555 cost me £0.60 each, which I believe is equivalent to just under $1.

Also I figured out what the bad connection was - one of the wires soldered to the pot broke off haha, so the braided wire is useless, especially such a thin gauge of wire.

It's -6C outside just now...I hope the temperature holds for when I get the San Ace monster fans, and that will be 260CFM of sub-zero air into my copper TRUE

Here's a really quick video with the Xigmatek fan. It's really hard to hear the increase in speed, so I connected the speed sensor and you can see that it goes from roughly 950rpm up to 2000rpm. Cant wait to get the San Ace fans!!

 

[LennyRhys]

Well I put it together on stripboard so that I could rule out bad connections, and right enough it worked flawlessly... untill I accidentally shorted the 12v against the ground. There was fire (no joke) so most if not all the components are likely fried...

I think I'm gonna take a break over the weekend and get more components at the start of next week (this time more than one of each) and put it together very carefully.