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Open source COM and carriers become 3D-printable computers

Aug 18, 2016 — by Eric Brown — 958 views

[Updated: Aug. 19] — Rhombus Tech’s Allwinner A20 based, “fully libre” EOMA68 COM and carrier boards can be installed in 3D printed mini-PC or laptop cases.

For the past five years, UK-based Rhombus Tech, led by developer Luke Kenneth Casson Leighton, has been developing a fully open source, removable computer-on-module (COM) in a standardized format known as “EOMA68.” Rhombus has now gone to CrowdSupply to help fund an “EOMA68-A20” module based on Allwinner’s A20 SoC, as well as a mini-PC and a 15.6-inch laptop built around the COM.

EOMA68 basics

The EOMA68 (Embedded Open Modular Standard 68) form-factor is based on the old PCMCIA form-factor, which has a 68-pin interface. Modules built to the standard can easily be moved from one device to another, including among multiple categories of devices. Don’t worry about slipping them into normal PCMCIA slots, though, since the EOMA68 spec wisely defined a slightly larger-than-PCMCIA outer shell dimension to prevent mishaps.

EOMA68 module from two angles
(click images to enlarge)

The developers of the EOMA68 standard made a point of defining its signal interface in a manner that would give the modules longevity. Quoting from the spec…

    Re-purposing of the PCMCIA interface and form-factor has been chosen to create portable mass-volume (100 million units and above) Embedded Computing Modules (Computer on Module). Mass-volume “Lowest Common Denominator” interfaces have been chosen, all of which have existed for over a decade, but are low-power enough to be standard across virtually all mass-produced powerful Embedded CPUs.

As a result of this EOMA68 module standardization, the two “EOMA68 Computing Devices” in Rhombus’s A20-based EOMA68 campaign should be upgradable when more powerful EOMA68 modules become available from Rhombus or others in the future. The systems can also be constructed using 3D-printable parts, thereby reducing landfill and consumption.

PCMCIA-sized EOMA68 COMs can move from device to device
(click image to enlarge)

The EOMA68 specification explains that in contrast to EOMA68, existing COM standards, such as Qseven or various SODIMM-style modules, are “not realistically user-upgradeable (not for the average person) because products require tools, technical knowledge in the selection of technically-compatible replacement parts, and expert knowledge in the handling of electronics for ESD-precautions before even opening the case.”

Rhombus EOMA68-A20 module details

The durably encased 85 x 55mm Rhombus EOMA68-A20 module supports its dual-core, 1.2GHz Cortex-A7-based Allwinner A20 SoC with 2GB RAM and 8GB NAND flash. There is also a micro-SD slot, a micro-HDMI port, and a micro-USB OTG port with bi-directional power. The module’s other onboard interfaces, fulfilling EOMA68 specifications, are listed as follows:

  • SD/MMC 4-bit with multiplexing to SD/MMC and SPI on 6x pins
  • 18-pin RGB/TTL (for LCD Panels and DVI/VGA/HDMI or other display conversion ICs)
  • 2x USB ports with Low/Full Speed and optional Hi Speed, 480Mbit/s (1x supports optional USB 3.0 or USB 3.1)
  • 4-pin GPIO with “External Interrupt” capability for fast hardware interrupt to the SoC
  • 1-pin PWM, multiplexed to GPIO
  • I2C
  • TTL-compatible UART (Tx and Rx only) multiplexed to GPIO
  • SPI up to 4-bit, multiplexed with 6x GPIO pins

Rhombus EOMA68-A20 module PCB front (left) and back
(click images to enlarge)

The EOMA68-A20 COM and systems are claimed to be scrupulously “libre” in both hardware and software, to the point where Rhombus omitted the usual Mali-400 GPU that accompanies the Allwinner A20, due to its lack of accessibility and documentation. So don’t expect much in the way of graphics.

As for software, the Parabola GNU/Linux-libre distribution that’s available preloaded on the EOMA68-A20 module is said to be so purely sourced that this version is expected to receive the Free Software Foundation’s “Respects Your Freedom” (RYF) certification before the first units ship in March 2017. Like this “Libre Tea Computer Card,” other versions equipped with Debian, Devuan, and Fedora 24 are available for $65 each.

EOMA68 enclosure options

You can extend these SBCs with a $20 breakout board that features a surface-mount PCMCIA header. There’s also a $35 pass-through card that inputs HDMI and USB signals and passes them on. The latter is said to turn a “Laptop Housing into a portable, battery-powered dock for your smartphone, USB-HDMI dongle computer, and tablet, or a second screen, keyboard, and mouse for your existing laptop or desktop PC.” There’s also a $14 USB and HDMI cable set.

Rhombus EOMA68 mini-PC baseboard prototype with EOMA68-A20 card installed, and its optional laser-cut plywood mini-PC enclosure
(click images to enlarge)

A $55, laser-cut plywood constructed Micro Desktop Housing can be used to turn the EOMA68-A20 COM into a mini-PC. The 4.5 x 4.5 x 0.5-inch case includes a user-upgradable slot for the EOMA68-A20, and adds two USB 2.0 ports, a VGA port, a 5.5mm DC jack supporting 7V to 21V, and a 20-pin internal GPIO expansion header. This gives you a full mini-PC for $120 plus any of the above add-ons you might desire.

EOM68 laptop case (left) and 3D-printable case design
(click images to enlarge)

There are three laptop kit options. You can choose a $450 Print-It-Yourself package, which gives you parts including cabling, boards (main, power, and controller, assembled and tested), as well as a battery, charger, keyboard, LCD, and CTP-LCD for trackpad. You will need to 3D-print the case yourself. A $500 option adds the 3D printed casing parts, including bamboo plywood panels, tested and assembled. For $1,200 you get the laptop pre-assembled, including the EOMA68-A20 module. One example of a free, 3D-printable EOMA68 compliant laptop case design is this YouMagine one by Leighton.

The laptop is unusual in that it offers both a 15.6-inch LCD display and a 4.3-inch backlit capacitive touchscreen built into the QWERTY keyboard assembly. The device uses plywood panels, and is available with full schematics and 3D-printed casework design files under GPLv3 license.

Full specs for the laptop extend the EOMA68-20 COM with features including:

  • EOMA68 slot (user upgradable)
  • STM32F072 MCU with firmware under GPLv3 license
  • 15.6-inch, 1366 x 768 LCD
  • 4.3-inch capacitive backlit touchscreen (instead of mouse trackpad)
  • Full-sized QWERTY keyboard including number-pad
  • 3x USB 2.0 ports (2x internal) in addition to EOMA68-A20’s USB-OTG port
  • 1W stereo speakers, built-in mic
  • CM108AH USB audio with stereo headphone socket
  • 90 x 60 x 8mm “special internal compartment”
  • Triple cable set for USB, HDMI and EOMA68
  • 10mAh battery (approximately 6-8 hours running time)
  • 1.1 kg weight

The EOMA68 form-factor was previously used in Make Play Live’s fully open source, Allwinner A20 based Improv SBC. The Improv was developed by Aaron Seigo and the KDE Plasma Active community, the apparently defunct group that also tried and failed to finish the open source Spark and Vivaldi tablets.

“Future designs on the roadmap over the next decade include tablets, set-top boxes, video camcorders on the one hand, and EOMA68-compliant COM upgrades ranging from ultra-low-cost single core to quad-core, octal-core, and beyond as newer SoCs become readily available,” wrote Leighton in an email to HackerBoards. “The well-known advantages of the COM strategy are brought to mass market levels.”

Further information

The EOMA68-A20 COM, mini-PC, and laptop are available for funding now on Crowd Supply, starting at $65 for the COM, with shipments due in March 2017. More information may be found at the EOMA68 Crowd Supply page and the Rhombus Tech website. The latest Crowd Supply campaign update may be found here.

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15 responses to “Open source COM and carriers become 3D-printable computers”

  1. Matthieu Gallien says:

    Is this Open Source Hardware with up to date published design files ?

      • Matthieu Gallien says:

        I read again comment from lkcl. The computer cards (the one with A20) is not free nor published. I believe he made my point, better support COM with published design documents than this.

        • lkcl says:

          hiya matthew. right. first thing: please read the page clearly, starting at the section “A Libre Approach”. secondly, are you volunteering to help provide, work on, or clean up the documentation? because, as i am literally the only person who has been working on this LIBRE project full-time for five years, i could use the help. if you’re not offering to help, please don’t expect me to accept your comments as being useful in any way. another way to put it would be: if you’re not prepared to help, perhaps you would like to offer some sponsorship funding so that i can pay someone professionally to provide the sort of look and/or documentation that you’re expecting, or perhaps recoup the personal investment of funds so that i can release the documentation that you’re expecting to see. if you’re not prepared to do that, then, again, please do not complain. deal?

          • Matthieu Gallien says:

            Luke, my comment is about whether EOMA matches my criteria for hardware to buy. As such, this is relevant to the discussion.

            People are really free to ignore them, but frankly speaking, EOMA is really not much more about freedom for users to modify and reuse than any other hardware out there (and less than some hardware easy to buy, (BBB for example)). Your comments are the only reason why I say this, nothing else (and even not your past endeavor).

  2. lkcl says:

    it’s libre hardware with 99% up to date published design files, to be 100% after i’ve recouped the financial investment of the past 5 years. “open source” is an infiltration and subversion strategy onto ethical business practices – dr stallman explained as “the reaaallly nice guy who just can’t say no”.

    a full write-up is available here on what’s available –

  3. Visitor says:

    Thank you for the article. Any offer of RYF hardware is worth publishing, since there’s so little available and the mainstream market seems to be going the wrong way.

    Now some small corrections about the article, based on the crowdsupply page:
    – For some reasons it lists the cable set for 14$ instead of 15$,
    – It says the 450$ PIY kit includes a “EOMA-68 COM”. I’m not sure if COM mean
    computer card (computer on module?) but other uses later in the article
    seem so. But as I understand 450$ PIY kit does _not_ include any coputer card.

    Also I recommend everydoby reviewing the updates in the crowdfunding page and the mailing list archive, there are lots of additional information there.

    Thank you again.

    • lkcl says:

      really appreciated the corrections, yes you’re right, PFY kit doesn’t include an EOMA68-A20 C.O.M. because you could get several (spares, one per family member, one for work one for home, one per student in a school all shared), or get the “passthrough” card to turn the laptop housing into something exactly like the NexDock or Superbook.

  4. Jerry says:

    I have to say, this is impressive design and the best luck with their system. OTOH, wth allwinner and ARM holdings. 😀 Your closed source crap GPU had to be cut off the chip ?! How lame is that? Does Allwinner have any statistics about how large a proportion of their users is able to display any graphics. It’s like 50% of the chip is defective. A mighty SoC with a fancy GPU but an external USB/HDMI dongle needed for graphics.. mkay. When is the time you start admitting the level of pee inside the brain is quite high?

  5. lkcl says:

    hiya matthew, i understand where you’re coming from. yes the Beaglebone Black and other hardware are of course easily available: in the case of the Beaglebone Black that’s sponsored by Texas Instruments, a billion-dollar company that would like to present their product in the best possible light. they would have paid something like $100,000 to $250,000 to have it developed by a third party Embedded Hardware Design company (or possibly paid employees in-house, end result same sort of cost). in the case of the Dragonboard 410c, Qualcomm paid Arrow Electronics, on Linaro’s recommendation (Linaro’s membership is $USD 1m per year btw) – estimated similar amount. in the case of the Efika MX “Smartbook”, Freescale would have paid around $250,000 to have that laptop custom-designed around the iMX5 SoC.

    so the general conclusion we can draw from these and many other examples is:

    (1) they’re multi-million to multi-billion dollar companies
    (2) they’re established companies contracting OTHER established companies
    (3) they’re paying a LOT of money to get the job done
    (4) theyre paying them to develop totally non-standard SBCs with an extremely limited lifespan
    (5) they’re “showcasing”.

    the implications should be clear, that this effort is, by total contrast, self-funded, designed to be long-term, is *from scratch* – there’s not been anything like it previously attempted – but most importantly you have to appreciate i am sure that for having worked on this for five *years* without any kind of VC funding and without *ANY* formal training in Electronics Design i’ve managed to achieve one hell of a lot!

    as it’s self-funded and run along software libre project lines, you’re either welcome to help, or, if you don’t wish to help, to wait until it reaches the kind of level that you’re expecting, or better, to back the project so that it can *get* to the kind of level that you’re expecting.

    please remember that you are not buying a “boxed product”. you’re not placing an “order”. this is not a “shop”. there is no “contract of sale”. it’s a *crowdfunding* campaign. you’re backing *ideas*. by focussing on comparing this to a BBB or other SBC, which is perfectly understandable (it’s a variant of a theme that i’ve seen countless times), you’ve completely missed the point.

    the point of the exercise is to reach mass-volume, save people money long-term on their computing devices, put *them* back in control of their own hardware, and incidentally keep stuff out of landfill as an indirect consequence…. oh: and do all of that in an eco-conscious way (so no massive VC funding which then results in accelerated timeframes, short-cuts taken due to having more money than sense, and so on).

    what you’re seeing with this crowd-funding campaign is the “bare minimum” required to reach that goal. by backing the project with a GIFT you’re helping to jump-start that…. oh and incidentally we will GIFT you with a reward. that’s crowdfunding: many many people forget that.

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