So, i have this cooling pad, and i want to be able to regulate the fan speed, so if you guys could make a circuit, the cooling pad is the Cooler Master Notepal X-Slim.
Well, telling us the type of electricity it takes, its voltage and its amperage would help us out. Without that information I can only guess. I'm assuming its 12 volts DC and draws under an amp so you can probably get by with a simple rheostat.
>so if you guys could make a circuit
Which bit of Do It YOURSELF confused you?
If you want advice on how to learn enough electronics to design & build your own circuit, check out the /ohm/ thread on here.
Pic related is the circuit inside of my Zalman NC-2000.
The value are in this post
I will be building the circuit myself, just not designing it, and i'm not thinking of taking an eletronics phd just for this, i can definately visit the /ohm thread but i don't know how they will teach me in a way that i will be able to build the circuit by myself...
Thanks for the answers.
The 5v going to the switch is the 5v rail from a USB port, you can omit that switch if you don't want to be able to turn it off and on. The LED is also optional.
MT1 and 2 are the fans, this particular cooler has 2 fans connected in parallel but if your cooler just has one you might need to experiment with the value of R1 if you don't get the adjustability range desired.
Well 2.5 watts (5v 500mA) is the maximum something like this can officially pull from a USB port, so they should be in the same ballpark.
I'm pretty sure this circuit will be suitable, transistor Q1 acts like a variable resistor in series with the fans whilst D2 protects it and C1 helps to "kickstart" the fans when the speed is set low.
This is why R2 is a relatively high value, to prevent the fan from stalling when trying to start up with the speed potentiometer dialed all the way down.
>Those are some tiny little fans
They are small but shift a surprising amount of air, keeps my laptop temperatures below 50C most of the time.
Mind me asking, what sort of hardware are you cooling?
I'll be changing the thermal paste on my laptop (hopefully I'll get the tube this week), and assuming that doesn't solve the slight overheating issue I have, I may have to invest in a cooling pad.
But there's a problem, i'm not counting on opening the cooling pad (it's new so it's under warranty), i was expecting that i could do this just making the circuit and connecting it to the usb port of the cooling pad.
How does your cooling pad get its power? USB port or external power brick?
Here is a speccy cap, laptop is from 2008 but idle the processor is 39c and the GPU about 45c. Under load the CPU really doesn't go above 50c with the cooler, without it easily hits 60C.
I would advise caution when removing heatsinks from laptops as the thermalpads can sometimes rip and they cannot be substituted with paste since the gap is too big (around 1mm).
What kind of heating problems are you having? If you can access the exhaust vents from the inside I would make sure it is free of dust as laptops can build up a thick carpet of dust on the inside of the grill after a few years.
Here's a speccy.
Keep in mind that these are idle temperatures with the laptop in 'Quiet Office' power mode.
If I were to switch it to High Performance mode and start doing something that requires a bit more horsepower I'll be hitting the 70°C mark fairly quickly.
I got the laptop in 2011 and back then the temperatures were around the same range as yours. Maxing out at around 55°C under load.
I do keep the laptop dust clean since it's fairly easy to open up.
The heatpipe design seems fairly simple as well.
I experienced a overheating and shutting down problem a few years back, turned out to be a thick layer of dust compacted against the inside exhaust radiator of the heatsink blocking airflow.
I was able to clean it without needing to remove the heatsink potentially damaging the thermalpads, since the heatsink assembly was shared between multiple IC's such as the processor with its thermal paste and GPU+Vram that all have individual thermal pads.
However if that is not an option I've used these pads before to replace the torn OEM pads on client laptops. http://www.amazon.co.uk/ARCTIC-Thermal-Pad-1-0-Conductivity/dp/B00UYTTDO6
The actual thickness you require will depend on the laptop, take a ruler and measure it to the nearest 0.5mm. I've found 1mm to be the most common thickness.
What laptop is it? Maybe I could find a service manual and check for you.
It's powered by USB, i can connect it to the laptop, to any USB port.
hmm it could be paste then if its doing that at idle, but are you 100% sure that nothing is running in the background? If the cpu and gpu share a heatsink it can transfer heat to the other device.
Well, there is the chance that I've got some garbage running in the background, but for that exact reason I also dual boot with Ubuntu, which produces identical temperatures.
And yes, the heatpipe is shared.
That would make the circuit nice and simple but bear in mind that it would not likely be able to bring the fan upto full speed what with its minimum 1.25v voltage drop.
The transistor arrangement as shown >>935079 solves this issue as the transistor selected has a very low saturation voltage of about 0.4v. This means the fan will see 4.6v at full tilt rather than just 3.75v with the LM317.
This is knowledge right here.
But if the max will be 4.6v it will never be at full speed because it is 5v?
I still don't understand how i will connect this when in the circuit the fans are in the middle of the circuit, i don't wanna have to open the cooling pad, i have the usb male and female already.
What about this? A simple Rheostat in series + project box and optional capacitor for kick starting the fan (don't go any higher than 10uF as this violates USB specs).
The 25 ohm version will be fine.
I forgot all about those lol, yes they will be perfect for this and make the circuit much more simpler. Here is the lowest dropout regulator I can find on farnell for a relatively cheap price http://uk.farnell.com/linear-technology/lt3080est-pbf/ic-ldo-reg-adj-1-1a-sot223-3/dp/1663553
Add a 1uF capacitor on the input and 2.2uF on the output to keep it stable. You'll want around a 560k potentiometer to get adjustable 0-5v out.
Give the repaste a try then but be careful not to rip the thermalpads.
I recommend this kit if you can source it in your country, comes with all the stuff you need to perform a proper cleanup and repaste. http://www.amazon.co.uk/Arctic-Silver-Ceramique-Arcticlean-Cloth/dp/B003YDUZNC
It's starting to get confusing to me, i know that there's many different ways to do this, so i want one that is capable to put the fan at max speed if necessary and i don't want to open the cooling pad, i already have the USB connectors.
So, what's the best option?
What about the 555 potentiometer?
I'm not just looking for the simplest, for example this circuit >>935079 with time i could easily build this, and i would have fun, if the best option is to have something that is the double of this one, then i don't care i would still do that.
But why is there circuits like the first one, when something like a rheostat does the same?
Thank you for your patience.
I'll keep that in mind.
Unfortunately the kit doesn't ship to my country. I'm getting the thermal paste from a friend anyways, he's replacing a heatsink on his PC and getting a tube of the stuff with it. Hopefully it's some quality stuff.
For cleaning I'll stick with isopropyl alcohol.
The fan being run from a USB port is only going to draw 2.5 watts max, so power dissipation is not an really an issue.
A switching regulator will likely add unnecessary complexity but OP could buy one of those pre-built modules on ebay.
The Rheostat doesn't offer the same amount of control as a regulator but its usually good enough for an application like this.
What about this circuit, you could splice it into an old USB cable. the switch lets you bypass the regulator to obtain the absolute maximum voltage thus speed to the fan.
That sounds great, i just didn't understant what is the switch doing, if i trun on the switch, will it give me the 4.65v right away?
What does the RG1 stand's for?
Do i get max speed with 4.65v even if the specs indicating that the fan is 5v?
Thank you so much anon!
Flipping the switch should give you 5V to the fan, full speed.
The switch is there to bypass the entire regulator circuit and with it, the voltage drop you'd get from the regulator.
RG1 is a location label for the linear voltage regulator (LT3080ET). I'm assuming it means Regulator 1.
The switch bypasses the regulator (RG1) and supply's a full 5v to the fan since the regulator alone can only put out 4.65v because of internal limitations. The switch effectively removes the regulator from the circuit.
Think of it as a "max speed" switch. On the flip side if you decide you don't need max fan speed anymore just flip it into the open position and the fan will go back to being speed controlled by the voltage regulator.
Well any linear regulator will have what is called a dropout voltage, that is the minimum voltage that can exist between the input and output before regulation fails.
Since the USB port already supply's 5V this leaves not enough voltage headroom for a full 0-5v of adjustable voltage.
The only thing that could do it is a buck-boost switching regulator, but it could also potentially over-current the USB port as it draws more than 500mA to compensate http://www.ebay.co.uk/itm/4-30V-to-1-25-35V-Auto-DC-DC-Boost-Buck-Converter-Solar-Voltage-Regulator-/181924112336
Besides those large capacitors could trip the polyfuse protecting the USB port as they are larger than 10uF which is speced as the maximum allowable on a USB device.
>What's the 50% on the VR?
Ignore that, its just what it's currently adjusted to in the schematic and simulation program I use.
>And the 10v in the capacitor's?
That is the max voltage rating of the capacitor, it should always be rated higher than the voltage you intend to use it with. 6.3v capacitors exist too but that is a bit too close to 5v for my liking.
>And what's the function of the diode?
This prevents the output pin from ever being at a higher voltage than the input pin and back feeding into it, this can sometimes happen briefly if you suddenly remove power (turning the computer off for example).
The diode bypasses the regulator in the reverse direction but doesn't do anything in normal circuit operation.
Thank's, i'm already searching to buy te components, witch one of these is the regulator? http://www.digikey.com/product-search/en?keywords=lt3080et
I can see that it has 5 pins, the ref in the diagram that you made is the vcontrol on the pin config right?
Im looking in Ebay too, i have a store here in town where i can try but i doubt that is cheaper...
Both of those are correct, they are just in different lead formations. One stands upright whilst the other is at an angle, I'd personally just choose the cheapest.
YMMV when sourcing parts on ebay, fakes are commonplace on there. You could end up with a regular LM317 that some chink has remarked as LT3080.
Here you go. Pin 1 of the IC is left unconnected and that small orange capacitor labeled "104" is a 100nF ceramic, it is optional and I highly doubt you'll need it since a computer already supply's a stable 5V.
Keep those electrolytic capacitors close to the IC as they are for keeping the regulator stable.
>it is optional and I highly doubt you'll need it since a computer already supply's a stable 5V.
Is it not for eating the ESD emitted by the pot's wiper scratching across its resistance material?
BTW those capacitors don't have to be exactly 2.2uF and 1uF, that is just the minimum the datasheet recommends.
For example if you can get 2x 2.2uF for less cost than buying two separate values then just go with that, as long as the total combined capacitance is under 10uF since this is a USB device.
I've always found that if it's worth going to the bother of getting at the cooling, you might as well replace the pads, paste, and fan while you're in there. Fans are cheap, tearing down laptops is a PITA, and a brand-new fan will usually be quieter than a worn one.
You're on the right track, its more of a problem when the input ripple is high but doesn't do any harm adding it anyway.
If using a metal potentiometer OP should solder a wire from the metal case to the negative rail, this shorts any noise pickup to ground and prevents any output voltage "jumping" as the initial hand contact charges up a small amount of stray capacitance.
I had to do this on an audio amp volume pot as every time I touched it there was a slight "pop" from the speakers.
This along with the extra capacitor should prevent any non-ideal real world influences from coupling into the adjust pin.
Since the shaft of the potentiometer is going to be exposed to the outside world I recommenced connecting the case through a resistor to prevent any accidental shorts or current loops.
>What's that 104?
>>935658 that small orange thing labeled "104" is a 100nF ceramic capacitor
>Does this two make the same effect? Wich one is better?
Same circuit as >>935658 but is just a way of preventing external noise from coupling into the adjust pin, it will still work without that extra mod.
>This last one, i have solder the resistor to the side of the Pot? What if it only has plastic covering it?
They are both the same circuit. The resistor on the pot is an optional extra you can apply to >>935658 to help with preventing external noise pickup.
If the pot has a plastic cover then the resistor to pot body mod becomes redundant.
Sure, that i already knew, as well as circuit wizard, i knew i have seen this type of diagram somewhere, i asked just to find a standard in this type of software.
Just for learning i tried to recreate the circuit, when i pull the switch it's all ok, but without the switch the motor doesn't get lower rpm's, the pot doesn't seem to work.
OP is back
Will this potentiometer work? http://www.ebay.com/itm/2PCS-WTH118-1A-2W-560K-ohm-Rotary-Taper-Potentiometer-/291605999651?hash=item43e5127023:g:4IcAAOSwo6lWN5rE
It has that 4th pin, is it there to make this >>935668 ?
The lady in the store didn't have 1uF 10v capacitor, i brought one that's 50v?