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Ask Slashdot: How Do I Make a High-Spec PC Waterproof?
jimwormold writes: I need to build a system for outdoor use, capable of withstanding a high pressure water jet! "Embedded PC," I hear you cry. Well, ideally yes. However, the system does a fair bit of number crunching on a GPU (GTX970) and there don't appear to be any such embedded systems available. The perfect solution will be as small as possible (ideally about 1.5x the size of a motherboard, and the height will be limited to accommodate the graphics card). I'm U.K.- based, so the ambient temperature will range from -5C to 30C, so I presume some sort of active temperature control would be useful.
I found this helpful discussion, but it's 14 years old. Thus, I thought I'd post my question here. Do any of you enlightened Slashdotters have insights to this problem, or know of any products that will help me achieve my goals?
I found this helpful discussion, but it's 14 years old. Thus, I thought I'd post my question here. Do any of you enlightened Slashdotters have insights to this problem, or know of any products that will help me achieve my goals?
Make it water-cooled! Duh.
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NEMA rates enclosures for their ability to withstand harsh environments. Search for NEMA enclosures and pick the one that fits your machine.
John
Can you give us curious folk a hint as to what you're doing?
http://www.skbspecialtycases.com/
I deal with this kind of thing once in a while when deploying hardware in freezing conditions (down to about -60F), and the truth is there aren't many options that are as small as you want.
This is the big question. Because, to riff off the 14 years old discussion, wireless has progressed leaps and bounds since then. So simply putting the PC inside a waterproof chest and using a combination of WiFi, Bluetooth, and a few wireless display technologies. This is what is presently on Intel's product roadmap anyway.
Your biggest problem is likely to be the monitor. Every means we have to produce significant amount of light (especially required for outdoor viewing), requires dissipation of heat. That means venting. Which means air holes. Which can get spray in it.
So really the question can't be answered unless you explain the purpose of the PC. Is it there to do things like take measurements? Can it be controlled from a mobile phone? (they're much easier to seal) This is what is needed to know how to give further advice.
Yes, you can find off the shelf computers which will do this and which have real GPUs.
http://lmgtfy.com/?q=ruggedized+pc
That's not going to help him. Apparently where he is at, the google is broken.
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Another idea which I like even better is to immerse the whole machine in mineral oil.
This is actually not that good of an idea. I ran a mineral oil rig back when I was in school, and the mineral oil dissolves the dielectric used in the "can" style capacitors used on almost all electronics. Over the space of about 3 years, the oil will destroy the exposed caps, and the machine will become flaky and ultimately stop working altogether. Also of note, the oil permeates and partially dissolves most silicone caulk and the plastics used for hot glue. Ultimately, its pretty nasty stuff in spite of appearing to be relatively inert.
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Double enclosed is best, but you probably don't have room for that. I've been putting stuff in food processing plants for 20+ years though where the conditions (especially during cleanup) are comparable. Find the smallest Pelican case (there are generic knockoffs, if you go with one check it thoroughly before trusting it) and equip it with a thermostatic heater to keep the temperature above 70F or so all the time to limit condensation. Pack in a big bag of dessicant because without double enclosure that still won't be perfect.
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I'm used to IP67-IP68+(IE. IP69K) for my work in designing autonomous subs(although I have other experience from GPU mining bitcoins), but NEMA 4X is specifically designed for the high pressure water jet conditions you're describing.
Although I'm curious WTF you're doing in a mobile/stationary weatherized application that requires a GTX970(A Jetson TK1 is easier to cool and good enough for most computer vision problems)? I'll answer your question directly instead of asking you how I can back out of your difficult design requirements:
First off: Lets assume IP55 is good enough:
http://cosmotec.stulz.com/en/products/ventilation/kryos-filter-fans/
These are the most cost effective IP55 ventilation fans I've been able to find.
If that's good enough for you: get on McMaster and order a NEMA 4X enclosure and consider yourself lucky that was all you needed. You have an industrial cooling problem, they have industrial cooling solutions. If you want some a little closer to your side of the pond: request a catalog from Rittal or get on their website and see if they have anything that meets your needs.
If IP55 is not good enough, and nothing as generic as a cosmotec fan or a cooled Rittal enclosure can get the job done: you can start by reading all the other responses and see if anyone has a better suggestion I'm unfamiliar with. If not, your job is either impossible, no one here knows what the solution is(or isn't saying if they do), or you have to go custom. That means in house or out of house design.
First off lets make something clear: you have a thermal management problem, not a water ingress problem. It becomes a water ingress problem when you are unable to adequately manage your thermal output without circulating air from the outside of the enclosure.
Shedding the heat of a 500-1000W PC using nothing but convection cooling with the enclosure skin/fins is difficult in the size you've described so the easiest thing to do would be to cheat and exceed your volume constraints via an external radiator in a location where your volume constraints are less of a problem. Supposing that is not possible: in a stationary application the ground becomes a pretty good heat sink if you dig down far enough. An alluminum water block burried beneath your computer circulating water through a NEMA 4X enclosure on the surface with the CPU and GPU pimped out with watercooling blocks. Excluding that as a possibility(mobile application?): pumping the heat in to a thermally conductive chunk of material large enough to dissipate it is still your preferred solution.
If there is no way around self-contained: you're either going to have to spend a lot of time and energy maximizing the thermally conductive surface area(doing analysis to determine it is adequate to meet your use case a high enough percentage of the time to matter), make the system fail gracefully under the conditions where it exceeds it's thermal management capabilities, optimize system thermal efficiency to the greatest extent possible by doing things like underclocking the CPU and using more CUDA/OpenCL for your code, redesigning your system(using a wireless modem to offload the processing requirements to a datacenter like Amazon AWS or even a closet at a nearby facility), or some crazy combination of all of the above in appropriate proportions to maximize the value to the customer(whoever that is) on the time frame/capital investment scale they are willing to pay for, and/or manage their expectations appropriately to where you can redefine your requirements, and/or claim it's impossible and hope a smarter/more ambitious engineer doesn't prove you wrong.
The correct answer is so situation specific it is difficult to tell you what to do without more information. These are some of the questions I would ask. Good luck with your bizarre requirements definition. I'm sure you've been painted in to a corner for good reasons and not because of an unwillingness to compromise on the "I want everything" mentality that makes programs like the F35 and F22 so fucking expensive.
Joking aside, I wonder why the OP is putting the number crunching in the outdoor box rather then splitting the work between an embedded system for data gathering (or whatever) and off the shelf desktop for processing.
I expect all of the number crunching is being done by an on-board AI trying to figure out how the heck to get away from the high pressure water jet...
I used to build cabinets for farm use, while I didn't go the immersion route I went with "the box" solution. Basically it meant that air intakes had double bends, sometimes triple bends with a drain hole at the bottom. Doors used a foam sealer, and exhaust was placed wall side. Farms are dirty places, if you're not dealing with feed dust, you're dealing with hay dust, or chemicals for plants, sprayers or livestock. There's always something that would ruin a machine quick.
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