Handling Systems Exposed to Extreme Temperatures?

NeoMagick asks: "I live in a rural town in the Pacific Northwest, and I'll soon be picking up a Shuttle system which will get mounted in the trunk of my car, and patched into probably an Alpine or Pyle in-dash LCD panel. This last week temperatures have gotten up to 105degF, and have been known to get to -10degF in the winters. I'm wondering if any /.ers have had issues with computers in cars in such extreme temperatures (overheating? freezing?), and if so what they did to solve such problems."

Comments

Hard drives

[adolf]

The component most likely to complain about temperature and vibration is the hard drive.

While your car's suspension will work rather well at isolating things from bumps in the road, it wouldn't hurt to get a little creative with mounting the drive. Suspending it between rubber straps might be a good idea, but watch out for things which are bouncy (resonant) -- it almost doesn't matter how much of the initial impact that your suspension absorbs, if it continues to shake the hell out of the thing several seconds after stuff should've come to a rest.

Hard drives come packed in open-cell foam, like a mattress pad, and seem to survive UPS Ground pretty well in such an arrangement. It wouldn't take too much creative engineering to fabricate an enclosure made predominately out of foam, but with a fan and enough room for air to circulate.

Temperature doesn't look like it's too much of a hassle, these days. I'm looking at the specs on an IBM 120GXP, which show it to be happy from -40 to 55 degrees celsius (-40 to 131 F). Since these are ambient temperatures, the drive is thus designed to withstand a trunk at 131 degrees with moderate airflow.

Since you'll be opening your windows and/or turning on the air conditioning Right Away on such blazing hot days, the hard drive should start recieving cooler ambient air at about the same time it starts generating appreciable heat of its own.

And in the winter, at -40, the last thing you're worried about is whether your hard drive will spin up. More important is whether or not the engine will, and if you'll be able to get the tires un-frozen from the ground. If you've got half a brain about you, you'll have the computer and stereo off, anyway, until the car is well under its own power...and, by that point, generating heat to warm up the electronics.

I'd avoid connecting the enclosure directly to the car's ductwork. Ever see a windshield fog up on the inside on a cold morning, just after you turn on the defroster? Imagine that happening to your in-car PC. Bad news. :-/

Since the motherboard you've chosen is so bloody small, have you considered putting it under the front seat? Things would get impossibly tight in a sports car with power seats, but should be do-able in almost anything else. There's no reason for the box to be more than an inch or three high. Sescom is a company who makes a large variety of metal boxes for do-it-yourself projects - chances are, one of them would fit your motherboard, hard drive, and some manner of DC power supply justabout perfectly, while remaining small enough to slide under the seat.

Drill or punch holes in the sides of the box, and mount the biggest, lowest-RPM fan you can find on the top of the box, blowing down. You might even be able to do away with having a dedicated CPU fan, and get by with a just large heatsink.

There's a few other things you might want to look into, with software. There's a way to poll hard drive temperature using a protocol called SMART - if the drive is cold, keep it spun up to reduce the viscosity of the grease in its bearings. Likewise, if the drive is fairly warm, spin it down when not needed to reduce wear and help ward off data loss (they are, of course, -much- more durable with not spinning).

Do the same with the CPU, if it suits you. If it's cold out, run the CPU full-tilt (seti@home, some random busyloop, cat /dev/zero > /dev/null, or whatever) to keep the motherboard components warm and well within design spec, which will help reduce condensation. Do the opposite on hot days - HLT the CPU when idle, so as not to make things any warmer than needed to get the job done, and take whatever other power-saving measures you can.

The goal here is to bring the board to some desired operating temperature, and keep it there until the car turns off.

All that said, you'll probably find that the most sensitive component of your system is the LCD display, which will be painfully slow/frozen on cold mornings, and either solid white or black after a hot day of sitting in the sun...and there's really not much to be done about it, unfortunately.

good luck!