Slashdot Mirror

← Back to Stories (view on slashdot.org)

Ask Slashdot: How Would You Suggest Making Rugged, Weather-Resistant ARM Systems?

Posted by BeauHD on from the open-for-suggestions dept.

New submitter pecosdave writes: I need suggestions for commercially-made ARM systems that will work in temperature ranges from -35F to 140F (-37C to 60C) for an engineering project. These things are going to be in metal boxes on the side of Texas Highways. The existing Intel systems we're using in other areas are all fan-less, but I'm not going to rule out systems with fans. Considering the extremes of Texas temperatures I'm actually contemplating putting fans on top of our fan-less systems anyways. Almost everything I can find pre-made with ARM is a bare board, or something not nearly as temperature tolerant as some Intel systems I can find. The very nature of an ARM processor should be more tolerant simply because they produce less heat, but I can't seem to find any manufacturers exploiting that fact. Slashdot reader pecosdave added more details in a comment: "It's more closely related to speed cameras, but it's not a speed camera. It's for a toll road, and its main job is to take pictures of a sign at about 10 FPS, though less is probably fine, with a time-stamp so if someone runs the toll we have a separate picture of the current price. If there's a problem with the sign it shows up as well. They just want something local to store it I guess in case the fiber link goes down. We're going to run it rather low-res too to keep the CPU and storage overhead low. I figure 640x480@10FPS is reasonable, but that's not set in stone."

6 of 194 comments (clear)

  1. Talk to an engineer by guruevi · · Score: 5, Insightful

    There are plenty of industrial manufacturers that will get you a custom chip in an IP65 enclosure. My company does these things all the time, but it's a bit more complicated than just putting something in a box. You have to spec the comms, peripherals, serviceability, lifetime, support, software, updates, ...

    Fans on top of fan-less design is a bit weird partially because you're going to sacrifice your IP rating and your fan shorting out or seizing up could bring the power and thus the system down. Also a fan is for moving hot air out and cooler air in. An ARM chip in most data collection circumstances won't get as hot as an asphalt highway in summer so you're just exchanging hot air for hot(ter) air, what's the point of a fan?

    --
    Custom electronics and digital signage for your business: www.evcircuits.com
  2. paint it white by arsenix · · Score: 3, Insightful

    A lot of ARM systems (even raspberry PI) will live life fine at 60C. You will need a nice passive heatsink inside your box (if it is large) or thermally couple the device to the box wall and put a passive heatsink on the outside. You'll need an active heater of some kind in order to operate reliably below 0C, but that is easy. Paint your box white too... that will help keep it cool in the sun. Good luck! Also post to an appropriate reddit rather than slashdot!

    --
    (this is offended to the end of comments you post, 120 chars)
    1. Re:paint it white by AmiMoJo · · Score: 3, Informative

      Posted something similar in the firehose. A bit of heating would also help with the camera and is probably the easiest option.

      60C isn't a problem, most ARM hardware is at least "industrial" temperature range which is up to 85C.

      Seal it up to keep dust and moisture out.

      There is probably an off-the-shelf CCTV option for this. They have CCTV in cold countries.

      --
      const int one = 65536; (Silvermoon, Texture.cs)
      SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
    2. Re:paint it white by bob4u2c · · Score: 3, Informative

      Think outside the box. Mount your camera at the top of a simple pole mount, then run the wires down to a box at the bottom where the cpu and guts are. Then dig a hole in the ground a few feet deep and bury the box. A few feet down it should stay cool/warm year round with no active cooling/heating.

      That is what we use to do with water pipes to keep them from freezing over in winter in the colder climates.

    3. Re:paint it white by Darinbob · · Score: 3, Informative

      But now the box will possibly be wet or moist all year round which has its own problems. By the side of a road means you'll get some odd toxic stuff there too so you need to make sure things are resistant to corrosion. Even if above ground you can often get a lot of salt corrosion if you're closer to the ocean.

      Beware of people intent on tampering. And animals. We had one product where we were considering a more expensive armored cable just to avoid problems with rodents.

  3. Re:my raspberry pi & 3D printer says by thegarbz · · Score: 3, Informative

    What a silly suggestion. The raspberry pi 3 is thermally challenged at room temperature. Adding 40C to that would put it well above Tjmax