Picture of El-cheapo (very) basic active laptop cooler pad
I recently received a used dell inspiron 5100 laptop. now for those of you who dont know - this is the laptop that heats up like there's no tomorrow due to some design flaw (i think i read somewhere there's a class action against dell). anyway free is free so i wouldnt go out an buy a $50 cooler for that!

instead i decided to spend some time and build one preferably as easily and cheap as possible!

note that you will need some minor electrical experience (if you ever added a light switch or outlet you should be OK)

EDIT(dec07): the laptop finally died this week. the hdd is dead by overheating. i may replace it but it's probably a question of time until it dies completely.

EDIT(xmas07): i replaced the dead hdd with one i had around and now i'm running the internal fan at high speed all the time to keep it cool. i also got a clearance fanless logitech laptop pad for less than $10 and dremel'd a hole into it to allow air intake for cooling. hopefully it will last longer this time :)

Step 1: What you need

Picture of what you need
  • some acrylic (11"x14"x0.093" ) or other type of material that you can use as a base. i got mine from the door & windows section of home depot
  • a USB cable from your dollar store (i used male to female cable)
  • electrical tape to insulate the cables
  • a fan - bigger is better but you need to test it first and make sure it works at 5 Volt. i got mine from a PC power source.
  • fan screws or glue
  • felt (the ones you put on the feet of chairs & tables to protect against floor scratches)
  • dremel tool or some other tool that you can use to cut holes
  • SAFETY gear (glasses)

note that i only need 1 fan for my laptop. you can add multiple fans however that will complicate the wiring of the project.

Step 2: Mark & cut the acrylic

Picture of mark & cut the acrylic
you need to mark and cut the base (acrylic) depending where your bottom fan(s) is located on your laptop. make sure your hole is big enough to fit your fan.

if your laptop has multiple fans on the bottom you need to have a hole in the acrylic for each of them! if you dont you risk overheating it. you can however just add a single fan (preferably under the bigger laptop fan)

Step 3: Cut the cable & add the fan

Picture of cut the cable & add the fan
cut the USB cable making sure you have enough length from the "normal" USB connector (which will power the fan). the USB cable will have 4 wires inside. you need to use the RED (+5 volt) and black (ground) to connect to same color cables of your fan. ignore the green and white wires. test before you make the final setup to confirm the fan is spinning. add the electrical tape over the connections.

make a note of the direction of the airflow! then check your laptop's fan. the cooler needs to drive air in the same direction as the laptop's fan. this is very important!

mount the fan in the appropriate direction (inlet or outlet).

Important note about the fan: USB ports can support up to 500mA (0.5A). your fan needs to be below this limit or it could damage your computer. most fans are rated 100-150mA (0.1-0.15A) which should be fine. fans that include LEDs may have higher power requirements however.

Step 4: Verify your work

Picture of verify your work
do a visual check and be proud of the result! unless you really messed up your measurements you should be all set on this step :)

Step 5: Final touches

Picture of final touches
now remove the protective plastic foil off the acrylic. you can add some felt to assure some spacing between the hot laptop and the plastic. this will allow some of the air blown by the fan to cool the rest of the laptop's bottom.

the book you see in the picture is the final touch. it's giving you the inclined surface you need to type comfortably and allows the fan to pull/blow air. i know you can add another piece of acrylic instead of the book but this is really meant to be cheap and fast :)

Step 6: Start using your laptop!

Picture of start using your laptop!
you're pretty much done. plug in the USB cable into the USB port of your laptop, power up and enjoy! assuming you tested your electric connections before you should be all set.
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alterator4 years ago
what´s the point of this, if your fan is blocked on the bottom... there is no sufficient air flow. :D
DIYSlacker (author)  alterator4 years ago
well since Dell decided to put the air intake fan at the bottom of the laptop, i've put my stronger fan just below it to blow air into that intake and help out the internal fan. i don't quite understand what your point is...
The fan you added is providing little to no airflow since the intake is blocked. If you did see significant temp changes it was because you gave more space for the stock fan to intake air.
Your right DIYSlacker that the fan would help cool it but Alternator is right about the fact that the additional fan is not going to work well (at least if it's set up like you have it in the picture) because there is hardly any space under the "new" fan for it to draw air in... There needs to be more space for proper air flow between the fan and the table/lap/floor/whatever...
Did you now that this 'ible has been linked to from here?
I built two ( one for wife ) out of scrap 1/4" plywood, copying the computer bottom air vents, and drilling out that pattern with a 1/2" drill. Different patterns for different models. Now we can both hold our laptops without overheating the machine or our legs. Mine also holds a pad and pen. Blowing out the computer with compressed CO2 is a good idea. One other trouble spot is the cooling fan itself. With a light , toothpick and CO2, you can check your fan for dust and lent build up. Stick the toothpick in to brace the fan and then use the CO2 to blow away the build up. Take care not to spin the fan with compressed air, you could damage the fan or the drive motor by over reving them. Thanks to all you guy's, every answer is part of the puzzle.
Brushless motors are awesomeley better
jakupl6 years ago
I just did this using only a box of pringles (cut up and used for elevation), a piece of cardboard, a nice and powerful fan that I found in the dumpster, an old telephone adapter (I don't want to use up usb ports, so I attached it to a wall plug.), and some string. It works great. Thanks for the inspiration.
shooby jakupl5 years ago
Using the telephone adapter is pretty brilliant...never seen or heard of a peripheral powered by it, good job.
ballack5 years ago
 how do u make the fan cable to usb input?
Mr. Thirty65 years ago
I made this out of an old laptop that I had been given.  I still need to find a protector for my fan, and I need something to give it some angle, but it's kinda cool. I like being a nerd, and most of my friends are nerds, so all of my friends liked it. Thanks for the idea!
nabeel186 years ago
i have a fan with rating 12 v Dc and 0.5A. but the USB port gives only 5 v. wont the fan damage the laptop
ATG nabeel186 years ago
fan wont run at its full capacity
DIYSlacker (author)  nabeel186 years ago
it should be OK. the fan can't draw more power than is available.
Nice ible my friend. Maybe a suggestion would be a a back rest for it as in for the placement of the laptop to insure the fan lines up correctly and that it wont slide off.
The Freeman6 years ago
You might also want to look into making some feet for you cooler. I don't quite think a book will cut it. It shouldn't be that hard to do.
tarzioo6 years ago
ugh! I wish i found this sooner! I just bought a laptop stand/cooler. Although i doubt mine would have turned out. My luck, I would severly hurt myself making it lol _
DIYSlacker (author)  tarzioo6 years ago
safety always comes first ;)
ya got that all wrong. it's safety third, after having fun and looking cool
haha exactly!!
Great Idea - Ive been wanting to build a cooler , since the cheapo ( $15 target) i purchased croaked! It was a plastic POS that sucked air instead of blew onto not good! I used to sell some awesome aluminium coolers but they are upwards of 100$ .. This simple quickie method, im sure outperforms the plastic "air sucker". I am concerned , however of the electronics .. using the wrong fan will result in overloading your laptops USB hardware and might cause PSU failure because of voltage spikes... be careful not to draw too much current from your usb port! use ohms law (http://en.wikipedia.org/wiki/Ohm%27s_law) to figure how much current your fan will draw.. any ??s email me at schicanoloco@sctechnm.com
DIYSlacker (author)  schicanoloco6 years ago
don't worry about the current draw. most fans have low current draw in the first place so it's quite safe to use USB. they even make USB fridges nowadays that use a fan and a special heat exchanger, all from one USB port. this one uses even less power.
Vixen83876 years ago
Nice work =)
I have one of these laptops too, but all i do is keep it on a hard flat surface with the back held up with bobbins to let more air flow through.(since it travels alot!) Your idea sounds good if it wasnt used regulary as a portable computer. Good work!
DIYSlacker (author)  Vixen83876 years ago
Thanks! i use mine as a desktop replacement so it's pretty much stuck in one place :)
bmlbytes6 years ago
You should <a rel="nofollow" href="http://www.instructables.com/id/Build-your-own-laptop/">build your own laptop</a>, then use this to keep it cool!<br/><br/>Great work, I need something like this.<br/>
ShadowJesus6 years ago
soo.. is the book included? ;p good instructable!
Calaad6 years ago
I have that book in step 5!
if you had time drilling some holes in the plastic wouldnt hurt
scob896 years ago
The overall design is a great idea, very easy to make, the base can be made of many different materials, but running a 12V fan off only 5V is not even worthwhile, due to the fact that the fan, if it even spins, won't spin very fast. I know the fan was free and all, but it would be worth it to find/buy a fan that was deigned to run off 5V
robotguy46 years ago
I think I have a way to make it even cooler: Ditch the acrylic for an aluminum cookie sheet.
mman15066 years ago
inspirons run very hot,im using a 1720 ,core 2 du,nividia graphics card with 256 dedcated video memory and 20" windscreen. it gets HOT specially when playing flight simulator x
drats6666 years ago
Another thing you can use instead of the felt(which don't give much clearance) is those small rubber feet stabalizers from radio shack. one side (top) is flat and has sticky thing on it to stick it to something(like the top and bottom of the cooling pad). Also I'd recommend adding a second piece of acrylic below the fan(or above depending on how you planed on using this). of course you'd then have to stablize the corners which can be done with a bolt and nut(dont tighten to much as it will crack the acrylic). if you want the entire thing to be slanted (like the book effect) you can use the second acrylic and bolt method and just use nuts on each bolt. You raise the back and put a nut on it, then put a second bolt below the bottom piece of acrylic. basically same for the front but you lower that end. If you want you can use a dreble to carve out small flat notchs for the bot and nut to rest on (gives it a little more stability and professional look)
NealCrosby7 years ago
I've been looking for instructions on how to do this! thanks for posting! So my laptop is going to need at least 2 fans, she's big and runs HOT. Will I be safe wiring both fans on a single USB cable?
that would depend on the power used by both fans? also another thing you'd have to take note of is not all laptops provide 500ma to a single usb, some provide to the set of usbs. example my laptop has 4 usbs total. 2 on left 2 on right. the 2 on the left have 5ma combined, the 2 on right have 5ma combined. Therefore I'd have to run 2 250 or lesser ma on fans. I hope this helps
hellstudios6 years ago
why don't the manufacturers smarten up and put the fan vents on the side!?!?
hifi-diy6 years ago
do not run your fans off usb,only if u have like four usb port to spare,usb is only capable of running 5 volts,and the standard fan is 12 volts,imagine the performance downgrade,it wouldn't be worth it. and some people here are going to run two fans off usb,just find a power adapter i found a perfect one from our Christmas decorative lights (broken) and it was perfect 24v,enough two run two fans fine.
hifi-diy6 years ago
Ive got a Sony vaio,it heats up quite a lot,so im doing similar do this project,i did not use led fans cause the power adapter i found was 24v,and i was running two 12v fans,and if they were led,the would presumably take up more voltage,therefore under powering the fans =(,i got normal fans and use simple bulb leds in the circuit,
Durrandi6 years ago
I wrote my senior theses on that book...
shooby7 years ago
Considering it's a free laptop, I would take it apart, and drill lots of holes in the paneling, the palm rests in particular.
hakkafusion7 years ago
nice~ but it'll be a lot more effective if you used a metal sheet instead of acrylic, the metal will dissipate heat a lot better than the plastic that insulates it.
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