Building a low-power dumb terminal
January 26, 2010 6:19 AM   Subscribe

Suggestions for hardware for a low-power dumb terminal?

I want to put together a kiosk-type computer that will be connected to a server on my LAN. It doesn't need much computing power or memory, as it's only going to be displaying textual data fetched from a remote server, and accepting input from a touch-screen. It will run some variety of Linux with X.

Since it will always be on, I'm looking for something that will use as little power as possible, and that's where I'm a bit confused. Most of the information I've found about low-power computing aims to maximize the CPU power to energy consumption ratio, but my terminal doesn't need much CPU power, so something like a Core 2 Duo LV or VIA C7 would be overkill. On the other hand, I don't know much about the power consumption of older chips. Could, say, an old Athlon XP 1GHz processor be underclocked to save energy? I only need around 200-500MHz and maybe 256MB of RAM. How can I best minimize power consumption with these specs?

Suggestions on low-power, low-muscle display adapters and storage devices would also be welcome. So far, I'm thinking of using a LiveCD-type setup from a USB thumb drive to avoid the need for a hard disk.
posted by Maximian to Computers & Internet (13 answers total) 1 user marked this as a favorite
You might want to look at mini-ITX hardware. Some of the low-power Via chipsets available for that form factor are ideal for this purpose, and not overkill at all.

Don't just repurpose a desktop chipset. There are exceptions, but most will run very hot and are unsuitable for a low-power solution. This is true even for some of the chipsets intended for laptops.

LED displays will be cheapest to run but expensive as heck, though any modern LCD is /usually/ pretty good, but check the various specifications first.

Depending on how much RAM is available for the display, you might need to consider more than 256Mb, especially if you are running a LiveCD. Remember, many LiveCD type systems actually have a root filesystem in memory, so you would not go amiss by providing 2Gb RAM.
posted by clvrmnky at 6:29 AM on January 26, 2010

Something based on this motherboard would work great.. (Low power consumption yet good 3D graphic abilities.)

posted by cowmix at 6:34 AM on January 26, 2010

Oops.. forgot the link.
posted by cowmix at 6:34 AM on January 26, 2010 [1 favorite]

I've been looking for an excuse to pick up one of these for awhile now.
posted by rokusan at 6:46 AM on January 26, 2010

How about a Sun Ray? Or perhaps an old-fashioned X terminal, or even one of those Wyse (and other) Winterms?

There's so much purpose-made equipment out there on EBay for cheap that it's almost a waste of time, and definitely a waste of money to spend more than 20 or 30 bucks on this project.

In a past life, I ran labs of 20 SunRays and a few more XTerminals, so if you end up going this route, feel free to bug me and I'll pass on whatever I know.
posted by Geckwoistmeinauto at 6:49 AM on January 26, 2010

If you do go the 'standard' PC route (yes, that includes mini-itx stuff) get the cheapest possible machine, skimp out on the ram, and run your X session on a remote computer that's got more horsepower. This can all be easily set up over the network.
posted by Geckwoistmeinauto at 6:51 AM on January 26, 2010

We've come a long way with innovating lower power chips in the last few years to the point where I think you'd probably want to look having an Intel Atom or other modern low power alternative as your CPU rather than trying to underclock an older power-wasting CPU. Not that that wouldn't work, it's just a bit like putting a V8 engine in a golf cart and limiting the RPMs to under 1000. Not exactly the most elegant.

I would start looking at the "Motherboard / CPU / VGA Combo" boards on NewEgg.

Some of the Zotec Ion models come with an external power supply like the ones laptops have, which is kinda cool. Then you can eschew the traditional PC power supply, and if you like, perhaps even the case altogether. Just mount the board someone inside your kiosk and go.
posted by BeerFilter at 6:56 AM on January 26, 2010

Further research indicates the HP T5525 (currently going for ~$25 on EBay) will boot and run Linux just fine.
posted by Geckwoistmeinauto at 6:59 AM on January 26, 2010

Unless your power is very expensive, the pay back on your lowest power option vs good enough is going to be quite a while.

I wouldn't screw around with an old chip, unless you have something lying around. Older systems and components are often not as good at idling at low power. Among other things, the power-supplies are typically less efficient, and often oversized, which hurts efficiency even more.

How much messing around do you want to do? If you just want something that works, get an inexpensive VIA based system with an appropriately sized power supply and be done with it. Atom systems with an ION chipset would also work, but are overkill and the cheapest is the ~$200 Acer Aspire Revo. The cheaper atoms with the older intel chipsets aren't so great since the chipset sucks down way more power than the CPU.

Whatever you do, don't use anything but motherboard integrated video. Add-on GPUs generally suck a fair bit of power, even at idle.

Oh, if you want to go hard-disk free, consider booting the thing over the net. I think most ethernet adapters have a basic bios that makes such a thing possible.

Sounds though like a used thin client that runs X might be the best bet.
posted by Good Brain at 9:50 AM on January 26, 2010

Response by poster: I had completely forgotten about the existence of thin X clients. This is almost certainly what I want, provided I can connect a touch screen to it and customize the OS. I had no idea they were so cheap.

Thanks also for the info on old chips not being very "greenable", so to speak; I had suspected this was the case.
posted by Maximian at 10:00 AM on January 26, 2010

Depending on the xterminal, you will either load the 'kernel' (not always the linux kernel) over the network (via tftp) or from local flash, and then point it at an XDMCP server. Some of the thin clients that typically run WinXP embedded on an ARM processor can either be net booted to the linux kernel or booted from local flash which can then be ran like a regular computer with apps running locally, or just used as a terminal with XDMCP. Either will probably work fine for what you want to do, but it's so much cooler to use it as a remote terminal. Or maybe it's cooler to have this teeny tiny low power linux box running. I can't decide. Either way, I need to buy more of those thin clients.
posted by Geckwoistmeinauto at 12:12 PM on January 26, 2010

might also look at ARM boards, such as the Beagleboard or gumstix. They're $150, and ~ $200, resp.
posted by at at 4:40 PM on January 26, 2010

Nthing HP T52XX's in particular, and thin clients in general, for the task you described.

Also nthing the advice that trying to underclock older chips for power-and-heat considerations does not end well - I tried to underclock an Intel chip so that I could run it fanless (or at least quieter), but while the CPU step down did result in an remarkably cooler chip, performance was flaky.
posted by eclectist at 7:48 PM on January 26, 2010

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