PWM to Analog converter circuit

Subliminal Aura · 15 Feb 2013 at 19:12

You know that just flew over my head don't you

Wish I had your skills, I would be building all the time.

Here's one for you that I'm sure you'll enjoy .... You're next project should be to extend this such that the fans illuminate to a colour that indicates how fast they're going !

red > amber > green :eek:

have fun mate

doyll · 15 Feb 2013 at 19:24

I make it a little over half way though that.. After that I would need to start looking things up on the web to understand.

Subliminal Aura · 15 Feb 2013 at 19:41

Yeah I think he's making it easy for us too LOL

I can code but can't solder or design circuits.... I think I've even got pic programming on my CV - better remove that pronto

snips86x · 15 Feb 2013 at 19:45

The Matrix said:

Wish my 600T looked that good

doyll · 15 Feb 2013 at 19:59

LOL. I'll never show the back of mine.. NEVER!

Resident · 15 Feb 2013 at 20:11

doyll said:
LOL. I'll never show the back of mine.. NEVER!

Mine's atrocious. But out of sight, out of mind lol

Subliminal Aura · 15 Feb 2013 at 20:14

I'll show mine if you show yours

Resident · 15 Feb 2013 at 20:29

Subliminal Aura said:
I'll show mine if you show yours

Now now, lets not hijack the thread.

Tealc · 15 Feb 2013 at 21:37

Subliminal Aura said:
You know that just flew over my head don't you Wish I had your skills, I would be building all the time.

Here's one for you that I'm sure you'll enjoy .... You're next project should be to extend this such that the fans illuminate to a colour that indicates how fast they're going !

red > amber > green have fun mate

That's easy.

PWM > low pass filter > comparator > some logic gates > link to transistor > 3 sets of led on fan circumference. I've done 12 LEDs on a fan before so this would be an evolution.

The low pass filter normalises the 0-5v pwm to a steady voltage. The comparator would check that voltage against its reference and when it goes high it would trigger a led. The logic gate would prevent all LEDs lighting up.

Would I do it though? Probably not.

I have created a very small circuit for Panyan that adjusted led brightness based on PWM. Look back through the thread. That was for a led strip. Not sure if he ever used it though. Worked a bewt though

Btw check the led sequencer link in my sig if you like led fans.

Back in topic now I think.

Subliminal Aura · 20 Feb 2013 at 17:22

You Sir are a genius..... THANK YOU

CPU Fan 1 is the PWM connected up to the converter driving 2 Noctuas
Idle (pwm level 1) = 725 RPM
Load (pwm level 10) = 1150 RPM

CPU Fan 2 is 3 pin connected to an SP120PE Fortunately the motherboard allows control so I left it as is
Idle (pwm level 1) = 1100 RPM
Load (pwm level 10) = 2200 RPM (Sounds like a jet but not a distraction when the case is closed)

Only tweaks I made were to loosen the pot - I was surprised that it took quite a few rotations so can only guess that it is very granular. Am I also right in thinking that the current shouldn't exceed 0.5Amps and I measure it via the molex +/- end point using a voltmeter ?

Big thank you and I sincerely hope you keep this project alive

EDIT: Fine tuning - I found that modifying the pot whilst at full rpm best for determining the levels

Tealc · 20 Feb 2013 at 17:43

Subliminal Aura said:
You Sir are a genius..... THANK YOU

Only tweaks I made were to loosen the pot - I was surprised that it took quite a few rotations so can only guess that it is very granular. Am I also right in thinking that the current shouldn't exceed 0.5Amps and I measure it via the molex +/- end point using a voltmeter ?

Big thank you and I sincerely hope you keep this project alive

EDIT: Fine tuning - I found that modifying the pot whilst at full rpm best for determining the levels

Thank you.

Those Pots are 20 turn 50k Ohm 0.5W rather than the 3/4 turn ones you normally get, which are rated at 0.15W and therefore not good for high current use.

Even though the pots are linear while in this circuit the pots work in a logarithmic fashion and at the higher power end you need to turn it only slightly to get a comparitively high change in output power. At the one or two fan end of the spectrum it can take a few turns to get the sweet spot.

Subliminal Aura · 20 Feb 2013 at 18:00

Cool, thanks for the update - Loving this

Resident · 20 Feb 2013 at 18:26

Just because Tealc likes to see these in place, I give you my Mk1.

Which is currently running 2 SP120PE fans attached to the H100i rad.

I've chosen to wrap mine in black vinyl just to aid blending in.

Subliminal Aura · 20 Feb 2013 at 18:43

Resident said:
Which is currently running 2 SP120PE fans attached to the H100i rad.

Nice.... What speed have you got your SP120s down to ? I'm thinking of putting a reducer on mine as my load temps are a mere 65C :cool:

Resident said:
I've chosen to wrap mine in black vinyl just to aid blending in.

Heh... and there was me getting jealous because I thought you got the 'special' edition

Resident · 20 Feb 2013 at 19:12

Subliminal Aura said:
Nice.... What speed have you got your SP120s down to ? I'm thinking of putting a reducer on mine as my load temps are a mere 65C

I've got mine set to a 20% minimum in ET6 (PWM control) which equates to ~1000rpm. If I take ET6 down to the absolute minimum (10%) then they'll slow to 580-600rpm. I can further drop this by changing my switch position on the converter. Mine has a 3 position switch rather than the POT on yours.

Subliminal Aura said:
Heh... and there was me getting jealous because I thought you got the 'special' edition

I suppose I have really, technically you could call it the first production model.

Tealc · 20 Feb 2013 at 19:22

Maybe I should get some black heatshrink

Subliminal Aura · 20 Feb 2013 at 20:27

Resident said:
I've got mine set to a 20% minimum in ET6 (PWM control) which equates to ~1000rpm. If I take ET6 down to the absolute minimum (10%) then they'll slow to 580-600rpm. I can further drop this by changing my switch position on the converter. Mine has a 3 position switch rather than the POT on yours.

Yeah I think 600rpm is possible... My mobo doesn't see rpms under 700 so I can't tell but when I put the reducer on the fan I could see it spinning slowly. Peak on load is ~1800 which is a hell of a lot nicer than 2200

Tealc said:
Maybe I should get some black heatshrink

+1

I was even tempted to ask you to make it all black cabling but knew that as an electronics purist loving your colour coded cables you would shout LOL !!! So I thought I better not ask

All the best guys ... Back to the machine as I had to replace the front panel as part of the job that I've been putting off for more than a week :eek:

Tealc · 20 Feb 2013 at 20:57

Subliminal Aura said:
I was even tempted to ask you to make it all black cabling but knew that as an electronics purist loving your colour coded cables you would shout LOL !!! So I thought I better not ask

Quite right too. A shiver just went down my spine even thinking about it.

Subliminal Aura · 20 Feb 2013 at 21:24

Tealc said:
Quite right too. A shiver just went down my spine even thinking about it.

ROFL

Rear shot for the booty lovers

I hid the converter in the 3.5" bay... I've now got a new problem though.... machine is so quiet that I can now hear the PSU :rolleyes:

Silence the never ending story !

Resident · 20 Feb 2013 at 21:55

Subliminal Aura said:
Yeah I think 600rpm is possible... My mobo doesn't see rpms under 700 so I can't tell but when I put the reducer on the fan I could see it spinning slowly. Peak on load is ~1800 which is a hell of a lot nicer than 2200

Mine will go upto 2200 if I disable control and stick it at full. However with the temps I get the PWM curve during OCCT testing doesn't push them over 1700rpm.

Subliminal Aura said:
ROFL

Rear shot for the booty lovers

http://i965.photobucket.com/albums/ae138/subliminalaura1/20130220_204548_zpsb10dff9c.jpg[/ IMG][/quote]

LOL! I wish my rear was that tidy. I think you'd **** the bed lol.

In fact, here's a pic:

[IMG]http://i.imgur.com/ODVbDnL.jpg

I hid the converter in the 3.5" bay... I've now got a new problem though.... machine is so quiet that I can now hear the PSU Silence the never ending story !

Click to expand...

I love my TX650M tbh. The fan rarely starts as the unit is semi-passive cooling. Until it gets to a certain load the fan isn't required so it doesn't run.