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Proposal: A New Standard for Encloseable Small Computers

Monitors are getting big. Computers are getting small. I think I’ve mentioned this idea before: a cavity in a monitor big enough to hold a Raspberry Pi, with the monitor providing power, video display, and a couple of USB ports for connecting peripherals like mice, keyboards, and thumb drives. Several of my Dell monitors have a coaxial power jack intended for speaker bars, and a USB hub as well. I’ve opened up a couple of those monitors to replace bad electrolytics, and as with most computer hardware, a lot of that internal volume is dead space.

The idea of a display with an internal computer has long been realized in TVs, many of which come with Android computers inside. That said, I’ve found them more a nuisance than useful, especially since I can’t inspect and don’t control the software. These days I outsource TV computing to a Windows 10 Intel NUC sitting on the TV cabinet behind the TV.

The top model of the Raspberry Pi 4, with 8 GB RAM, is basically as powerful as a lot of intermediate desktops, with more than enough crunch for typical office work; Web, word processing, spreadsheets, etc. With the Debian-based Raspberry Pi OS (formerly Raspbian) and its suite of open-source applications, you’ve got a desktop PC. More recently, the company has released the Raspberry Pi 400, which is a custom 4GB RPi 4 built into a keyboard, with I/O brought out the back edge. (In truth, I’d rather have it built into a display, as I am extremely fussy about my keyboards.) Computers within keyboards have a long history, going back to (I think) the now-forgotten Sol-20 or perhaps the Exidy Sorcerer. (Both appeared in 1978.)

What I want is breadth, which means the ability to install any of the modern small single-board computers, like the Beaglebone and its many peers. Breadth requires standardization, both in the monitor and in the computer. And if a standard existed, it could be implemented in monitors, keyboards, printers, standalone cases, robot chassis, and anything else that might be useful with a tiny computer in its tummy.

A standard would require both physical and electrical elements. Electrical design would be necessary to bring video, networking, and USB outside the enclosure, whatever the enclosure is. (I reject the bottom-feeder option of just leaving a hole in the back of the enclosure to bring out conventional cables.) This means the boards themselves would have to be designed to mate with the enclosure. What I’m envisioning is something with a card slot in it, and a slot spec for video, network, i2s, and USB connections. (GPIO might not be available through the slot.) The boards themselves would have slot connectors along one edge, designed to the standard. The redesigned boards could be smaller and thinner (and cheaper) without the need for conventional video, network, audio, and USB jacks. (Network connectors are increasingly unnecessary now that many boards have on-board WiFi and Bluetooth antennas.) Picture something like the Raspberry Pi Zero with edge connectors for I/O.

Defining such a standard would be a minor exercise in electrical engineering. The big challenge would be getting a standards body like ANSI interested in adopting it. The Raspberry Pi Foundation has the engineering chops, obviously, and once a standard has been created and proven out, groups like IEEE or ANSI might be more inclined to adopt it and make it “official.”

I understand that this might “fork” the small-board computing market between GPIO boards and non-GPIO boards. Leaving the GPIO pads on the opposite edge of the board is of course possible, and would allow the board to be enclosed or out in the open, or inside some other sort of enclosure that leaves room for GPIO connections. A big part of the draw of the small boards is the ability to add hardware functionality in a “hat” that plugs into the GPIO bus, and I don’t want to minimize that. I think that there’s a market for non-GPIO boards that vanish inside some larger device or enclosure that provides jacks for connections to the outside world. The Raspberry Pi 400 is an excellent example of this, with GPIO header access as well. What I’m proposing is a standard that would allow a single enclosure device to be available to any board designed to the standard.

Ok, it would be hard–for small values of hard. That doesn’t mean it wouldn’t be well worth doing.


  1. Jason Bucata says:

    I think a de facto or industry-consortium standard would be better than trying to get ANSI involved. That’s what we’ve got with ATX and ITX. Also USB doesn’t appear to be an ANSI/ISO standard. Wifi is managed by IEEE. VESA mounts are specified by… VESA. Really, unlike the old days of language development, it appears that ANSI and ISO are much less relevant to tech these days.

    You might like the ETA Prime YouTube channel; he covers a lot of Pi-style single board computers and innovative chassis form factors for them.

    I’m picky about keyboards too but what I’m wishing for is an RPi 400 with M.2 support built in. So far many people seem to feel that SD cards are just fine for storage.

  2. Michael Black says:

    The Sol was in Popular Electronics for July 1976, and was at a comouter show in August.

    Computers are already in monitors. I’m not talking about my tv set (which runs Linux), but those all in ones, that include some Macs, and even laptops.

    Limits to expansion, limits to how much upgrade. Space limits and lack of compatibility.

    So better to define specs, and let companies fikl it, than picking a Pi and hoping others follow.

    Maybe better to work on more computers that mount on the back of monitors.

  3. TRX says:

    Dell has been selling monitor/computers for almost as long as they’ve been selling LCDs. They look like laptop motherboards; no slots. I’ve kept an eye out for refurbs, but I’ve never seen any used ones come on the market; maybe I just missed them every time.

    I have a client that has two computers on every desk; one hooked to a general purpose network with an internet connection, the others hooked to a secure internal network with its own wiring; completely air-gapped from the outside world. Their office A/C system struggles with the heat load, so I’ve been buying low-power equipment when practical. The internal network is just a server and PCs running terminal emulation; I’ve been moving those to Raspberry Pis as their old monitors fail and are replaced with new ones with HDMI ports. I haven’t had much luck with HDMI-to-VGA adapters. I stick a Pi to the back with Velcro tape, plug in all the cables – I have a pack of sticky-back cable holder thingamabobs to make it look neat – and away they go.

    Velcro tape isn’t as fancy as a new monitor back, but it’s working for me…

    As an intermediate step, if someone were to make Pi cases with ears to let you screw them to the VESA mounting holes on the back of the monitor, it would probably look neater than a red-and-white box stuck on with Velco.

    I’ve been watching some of the x86/Windows compatible boards. The outward-facing machines, by edict, must be running Windows, even though most of them do nothing more than word processing. Something that’s reasonably responsive under that sort of load, that doesn’t have any weird driver dependencies, it definitely on the to-try list.

    1. There are definitely VESA cases with “ears.” I have a couple of them, and a link below to the one my RPi3 lives in. I found it by searching for “VESA Raspberry Pi case.” It’s on Amazon for $20:

      Carol and I used Dell USFF machines for a lot of years. And I think you’re right: Those look like laptop mobos to me. I’m about to replace the last one in regular service with an Intel NUC. I’ve seen used PC-in-a-monitor machines, but they must be popular, as they’re scarce and when I see them, the prices are nuts for old machines sometimes running Vista. If I could get a dead one cheap, I would tear out the mobo and “stuff” it (ha!) with a Raspberry Pi 4 with 8GB.

  4. Jason Kaczor says:

    *In theory*, this is one of those actual areas where a 3d-printer might be useful.

    Print a VESA-compatible extension/bridge that will then have decent mount points for arbitrary SBC’s or other components. (A SBC is likely light enough that the PLA wouldn’t be a problem from a structural perspective.

    For a NUC, the following is something I have looked:

    But, I have been holding off, because that is not a hobby I have time to get into right now…

    1. I feel the same way about 3-D printing: I have enough projects in play to keep me busy all the time and then some. Learning an entirely new technology doesn’t call to me right now. We have two NUCs here, and they take up so little space that I don’t feel any strong need to bolt them to the back of the monitor. Of course, if I wanted to I could; two years ago I put a dual-arm monitor stand on my steampunk computer table and mounted a Dell monitor on one arm and an HP dc7900 USFF on the other arm. It worked out very well, and I described it here on Contra:

      A NUC would work just as well, as there’s a VESA bracket on the end of both arms. The dc7900 has VESA threaded holes on its two case panels. The dc7900 is…ok. It’s getting old. Carol’s using one, and I’m about to move her over to the new NUC I bought late last year. Her dc7900 has some quirks that may cook down to an intermittent in the front-panel USB circuit board. I’m tempted to pull out the mobo, scrap it, and see if the power supply could make an RPi go. On the other hand, I have a sketch of a sort of VESA-mountable breadboard for the steampunk lashup, to take the place of the dc7900. It’s a live project and I hope to get some real work done on it this winter. The idea is to put an RPi 4 on a piece of perforated metal like those they sell at the robot parts places, put a breadboard block beside it, plus brackets to hold stepper motors or other mechanical gimcrackery. I’ll put a photo here once I have something complete enough to warrant a photo.

  5. TRX says:

    Most newer LCD monitors seem to shape the back panel around the power supply and control board, but the Acer monitor I took apart last week has *almost* enough room for a Pi back there… actually, with some right-angle connectors, it would probably fit.

    On the other hand, just sticking a Pi on the outside means you don’t have to dink around with running cables or mounting sockets.

  6. Spencer Arnold says:

    “once a standard has been created and proven out”

    from my memory of the 80s and 90s once this happens, Microsoft or Sun will join in then try and insert their own additional standards over top to try and co-opt the movement. Better to stay off their radar.

    1. True to an extent, but I think most of what MS did with standards involved software more than hardware. What I’m proposing is kind of mundane: a mechanical mounting standard (a la VESA) and an interface standard allowing many different boards to connect via a single or perhaps two connectors. Software really doesn’t come into play beyond the fundamentals like SATA, USB and the network stack.

      We’re already seeing an emerging de facto standard in the Raspberry Pi. I’d love to see a board connector standard something like S100. That would be a huge win, but simply getting a mounting standard in place would be useful.

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