Case with fan


19 posts
by Buggington » Sat Aug 11, 2012 9:02 pm
Hello :)

Having installed RaspBMC on my Pi I've noticed it's getting particularly hot (constantly using around 60-100% CPU) when it's been on for a while, so much so that I can feel it through the plastic case. I want to find a case where I can mount a small CPU fan on top, but I haven't really seen anyone do it yet. Has anyone managed to do it here, or can they recommend a way to do this?

Thanks :D
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by fredjam » Sun Aug 12, 2012 1:22 am
You don't need to do this. This is a mobile phone chip and will operate for many years
inside a mobile phone without a fan of any sort of cooling. If you are over clocking
your cpu then you could buy one of the small stick on heat sinks available for a few
pounds (on ebay.) but apparently this isn't really necessary either.
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by Buggington » Sun Aug 12, 2012 1:48 pm
You're right, I don't need to do it, but it would mean it'll last longer. I might be wrong here but it strikes me that a phone's chipset wouldn't be running at 60% usage the whole time (mine certainly doesn't).

I've been planning on getting the heatsinks below - obviously these are the first step towards cooling, otherwise I could have a fan but still not dissipate any heat.

http://www.ebay.co.uk/itm/330758220781? ... 890wt_1140
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by zulucat » Sun Aug 12, 2012 4:38 pm
One solution would be to use a Bud RPI Case. Drill some holes in the top & attach a 5v DC fan. I have one of the Bud cases & I think there would be enough room inside to mount short heat sinks. Here are a couple of links so you can see what the case looks like.

http://www.budind.com/view/Plastic+Boxes/Microcomputer+Enclosures

http://www.alliedelec.com/Search/ProductDetail.aspx?SKU=70231926


I also found a 5v DC fan that draws less than 100ma of current so that you could hook it up to the 5v pin on the GPIO connector.

http://www.alliedelec.com/search/productdetail.aspx?SKU=70226137

Good luck on your project - Doug
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by Buggington » Sun Aug 12, 2012 6:01 pm
That looks like exactly what I'm looking for - thanks! Unfortunately, it seems to be in the wrong country- I'm in the UK!

Any idea how I would connect to the GPIOs? It's an entirely new thing for me :oops:
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by zulucat » Sun Aug 12, 2012 8:15 pm
Buggington wrote:That looks like exactly what I'm looking for - thanks! Unfortunately, it seems to be in the wrong country- I'm in the UK!


Mouser UK carries both the case and 5v DC fans. Here's a link to their web site:

http://uk.mouser.com/

Do a search for Bud PS-11591 and for 5v dc fans.

Any idea how I would connect to the GPIOs? It's an entirely new thing for me :oops:


Any way I can think of to provide power to the fan involves, at some point, soldering a couple of wires. Do you have the tools and experience do do that?
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by Buggington » Sun Aug 12, 2012 8:20 pm
Cool, thanks. I've had to solder quite a few wires before, so shouldn't be a problem. I shall google for a wiring diagram. Thanks for the help :D
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by zulucat » Sun Aug 12, 2012 10:16 pm
Buggington wrote:Cool, thanks. I've had to solder quite a few wires before, so shouldn't be a problem. I shall google for a wiring diagram. Thanks for the help :D


Here's a link to information on the GPIO pins on the RPI.

http://www.elinux.org/RPi_Low-level_peripherals

Location of the GPIO pins is shown here:

http://www.raspberrypi.org/faqs


I can think of a number of ways to get power to the fan --

1. Solder directly to the +5v & GND pins on the connector. I would not do this as you might make
the connector unusable for future projects.

2. Use jumper wires that mate with pins on the GPIO. Solder to the jumper wires.

https://www.adafruit.com/products/266

(I know, I know. ;) It's a US company but it illustrates the kind of jumper I'm talking about).

3. Get a prototyping board that plugs onto the GPIO pins. Connect to the protoboard.

http://shop.ciseco.co.uk/slice-of-pi-add-on-for-raspberry-pi/

4. Get a USB y-cable. Cut off one of connectors and solder to the +5v & GND leads of the cable.
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by stevech » Mon Aug 13, 2012 1:31 am
much better to use a conductive heat radiator than a fan for such a board.
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by Buggington » Mon Aug 13, 2012 9:57 am
Zulucat: I've been having a look at some of the fans on the Mouser site and this seems to fit the bill

http://uk.mouser.com/ProductDetail/ADDA ... jxUmypo%3d

Also, do you think these heatsinks would fit in that case? They're 10mm high apparently. It's a little touch and go on whether they'd fit in my Mod My Pi case, that's for sure.

http://www.ebay.co.uk/itm/330758220781? ... 890wt_1140

Stevech: I am doing that too - you can't have a fan with no heatsink.
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by robwriter » Mon Aug 13, 2012 11:39 am
Buggington wrote:You're right, I don't need to do it, but it would mean it'll last longer. I might be wrong here but it strikes me that a phone's chipset wouldn't be running at 60% usage the whole time (mine certainly doesn't).

I've been planning on getting the heatsinks below - obviously these are the first step towards cooling, otherwise I could have a fan but still not dissipate any heat.

http://www.ebay.co.uk/itm/330758220781? ... 890wt_1140


I don't we know for usre that cooling the Pi by a few degrees makes it last longer. It's common sense that it probably will, but we don't know which component will tend to fail first.

Considering the Pi is cheap, cases/fans cost money and fans have limited lifetimes (less than the Pi if it's permanently spinning) then it's not a given that this is actually going to save money in the long run. Especially as it's likely that if your Pi does fail in 5 years due to heat, you can probably get a second hand one on eBay cheap.
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by bredman » Mon Aug 13, 2012 11:54 am
Before you invest your time and money, please keep the following in mind...

1. The chips in the RPi are supposed to run hot, they are designed to operate safely to 120 degrees C.

2. The fact that the case feels warm means that heat is exiting the system. The heat is dissipating through the box. If the box didn't feel warm I would be more worried.

If you proceed with this project you may learn something about electrics and mechanical design, so it may be educational for you. But it will not affect the performance or lifespan of the RPi.
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by Buggington » Mon Aug 13, 2012 12:25 pm
True, thanks for all the input. I'm going to continue anyway, partly because it would be quite a cool thing to have sat on my desk. I had no idea that they would be able to run up to that temperature - my logic was if an nVidia graphics card couldn't handle 130 degrees then a £30 computer certainly couldn't.
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by RaTTuS » Mon Aug 13, 2012 12:30 pm
I think he main chip is rated do 70deg C not 130
I've never seen mine go above 51deg C, normally 44
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by bredman » Mon Aug 13, 2012 12:32 pm
The main chip is rated to 120C in a still air temperature of 85C.

The hottest part of the board will be the ethernet chip, this has been measured at over 60C in normal operation, but this is well within the design limits.
Last edited by bredman on Mon Aug 13, 2012 12:33 pm, edited 1 time in total.
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by Buggington » Mon Aug 13, 2012 12:32 pm
How do you guys know the temperature then?
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by cashaw » Mon Aug 13, 2012 12:34 pm
As a side, I have an ARM based NAS (Excito Bubba) which runs 24/7 and consumes around 8 watts of power. It's temperature is always around 60-70 degrees and has been running perfectly happy for 2+ years without issues.

As said in the previous reply, if the Pi is able to disipate heat then a fan is not needed. In fact one of the things I love about the Pi is that it runs silently in my living room or bedroom, no fan or HD noise and all my NFS drives (which the Pi's are connected to) are stored away where the noise does not disturb me.

My HiFi / TV and many other fan-less systems contain microprocessors which get much, much hotter than my Pi and they have been running for literally decades without failure, so I wouldn't expect my Pi to have issues.
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by Buggington » Mon Aug 13, 2012 12:40 pm
cashaw wrote:It's temperature is always around 60-70 degrees and has been running perfectly happy for 2+ years without issues.


Hmmm... That's starting to change my mind a little.
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by zulucat » Tue Aug 14, 2012 3:45 am
Buggington wrote:Zulucat: I've been having a look at some of the fans on the Mouser site and this seems to fit the bill

http://uk.mouser.com/ProductDetail/ADDA ... jxUmypo%3d

Also, do you think these heatsinks would fit in that case? They're 10mm high apparently. It's a little touch and go on whether they'd fit in my Mod My Pi case, that's for sure.

http://www.ebay.co.uk/itm/330758220781? ... 890wt_1140


FAN - Looks OK. It's small enough to fit nicely on the Bud case. Make sure that your power supply can handle the additional load of the fan (100ma).

HEATSINKS - They only stick up 10mm which is less than that of the dual USB connector. That means that any case that clears the USB connector will work. The Bud case will work with room to spare.
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