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How small could you make a working computer? Answered

I originally wrote this as a reply to rimar2000 in another forum.  It seems sufficiently interesting to warrant a separate discussion thread.

How small could you make a fully-operational personal computer (say, something with the capability of a Netbook).  I think the technology already exists to make one the size of a deck of playing cards:
  • Hundreds of GB of storage in something the size of a little MP3 player
  • WiFi transceivers fit inside a standard USB "thumbdrive" casing
  • Projected keyboards could be integrated (not a separate box)
  • The same technology could make an RGB projected display
  • A small footprint CPU (maybe with "embedded Linux") ought to be practical
Without a big display, hard drive, etc., you don't need much power at 5V to drive everything.  A standard cellphone battery (say 3.7V, 1000 mAh) ought to be enough to run such a machine for a couple of days between charges.

I'm not competent enough as an electronics engineer to prototype something like this, but it seems like a really great challenge for the DIY experts out there.  How small could you make a working PC using existing current technology?


<a href="http://www.linuxfordevices.com/c/a/News/Linux-Space-Cube-ready-for-blastoff/">Pretty darned small.</a><br />

Thank you, Cameron! I was both rolling on the floor and rather uncomfortable with the quote from a review towards the end of the article,<blockquote><div><em><span class="txt">The review tested the system as drawing a low 5 Watts</span></em><span class="txt">[sic]</span><em><span class="txt"> of power, and reports that "for such a small and low-powered PC, the Space Cube is actually pretty nippy."<br /></span></em></div></blockquote>A bit anachronistic to be sure, but still, referring to a Japanese product as "nippy"?!? How did the copy editors let that one through?<br />

sorry this is off topic but does anyone know why i am seeing html code above instead of seeing what the html actually does?


I got the Space Cube link via Hackaday, but I see <a href="http://www.linuxfordevices.com/c/a/News/Tiny-tactical-mission-computer-runs-Linux/">another computer in the links at the bottom</a> that appears to be much more of a functional computer, albeit somewhat larger (3"x4.3"x7" instead of 2"x2"x2.1"). While the Space Cube only has 64MB of RAM and a 200MHz-300MHz processor, the DuraCor has 1GB RAM and a 1.4MHz processor, which is better than most netbooks. It doesn't have a connection awesomely labeled "<a href="http://en.wikipedia.org/wiki/SpaceWire">SpaceWire</a>", but it all of its connections are MIL-spec screw-on connectors, which are also cool, and the thing could keep running after it got run over by a dump truck.<br /><br />I saw one of those handheld projectors at Office Depot today...it was a non-working display model, I was really hoping to see one in action.<br />

Were there any editors that looked at it? There's a lot fewer of them about these days...



8 years ago

As many people have pointed out, the average smartphone has more processing power than my desktop from ten years ago, and I did publishing and spreadsheets and played 3D games on that.

If you are looking for a "proper" computer, I think your playing cards estimate is about right.

Computer: Gumstix
Tiny, 600MHz processor, integrated 802.11 WiFi, add-on boards to interface with peripherals and add network connections etc- everything you need for the core of the system.

Keyboard/mouse: Gumstix computers can use USB through a breakout board, or a microcontroller can be used to interface with a keyboard.

Display: this is where problems arise. Projected displays aren't quite mature enough to be a proper solution in this much space, but there are pico projectors emerging which could project the display onto a nearby wall.

Power supply: a couple of Li-Ion phone batteries could power the device for a few hours, or you could give up trying to make it entirely self-contained and plug it into a wall-wart, or use inductive charging (a bit of a cheat).

If you don't mind not having a keyboard, mouse or display, the Sheevaplug is a decent existing product, and I'm sure it wouldn't take too much to add a couple of USB sockets for mouse/keyboard and a video output for a monitor or pico projector to one of those.

Thanks, PKM!  I knew about smartphones when I posted this; that was kind of my point.  These devices have crappy keyboards and displays for anything like real work -- try doing a multipage accounting spreadsheet for a corporation, or a CAD design, on an iPhone.  You won't be doing it for very long.

If you have to plug an external mechanical keyboard into the device, then the size of that keyboard counts toward the total size of the system.  Same goes for external displays.

My point was, how much of all this separate modular tehnology (including pico projectors) could be stripped of their casings and independent power supplies and company logos, and all put into one single box?  And how big or small would that box be?

Tethering to a wall-wart isn't completely unreasonable if you're doing fixed-site work, but portability and chargeableness :-) are obvious consequences of making a fully-powerful "desktop" computer fit in your pocket.

In that case, I think about the size of a Psion is a sensible minimum.  It has space for the components mentioned above, a decent-sized battery (at a draw of several watts, a phone battery wouldn't last long) and a usable keyboard.  Those laser keyboards are cool but I refuse to believe using one with no touch feedback at all is going to be pleasant.

Here's an idea- my current computer keyboard has at least four iPhones-worth of spare space at the top taken up by 8 mostly-useless media keys.

Why not go the route of the BBC micro et al, and have a full-size keyboard with the computer built into it?  You could easily fit a pico projector, small laptop battery, Gumstix board and so on into a PC keyboard.  I realise that what I have just described is quite similar to a crazy device called a "laptop", but if you want a really usable keyboard you need a keyboard.

That would be quite a fun project- find a keyboard with enough spare space in it and build a computer entirely inside it. Maybe a job for Ben Heckendorm?


Reply 8 years ago

OK, last post.  What about the size of a tangerine?

That includes a CF card reader, sound output, wired ethernet and even a VGA monitor port.  That is exactly the hardware I'd want for my hypothetical keyboardputer.

The LinuxStamp and CherryPal linked from that article might also interest you.  Getting the display out seems to be the hardest part- the "silver bullet" for this application would be a chip that can take character or pixel blitting input and generate the monitor signal on the fly.


Reply 8 years ago

Yes, I know I promised last post, but it seems these are more ubiquitous than you might think.  How about one you can wear on your face?

It doesn't go into the details of how the video output works, but it seems it's not overly difficult to output VGA from the Gumstix moard they are using.  Maybe my computer-in-a-keyboard idea isn't so crazy?  It also states a power consumption of about 4W, so a few phone batteries could legitimately power one.  Maybe take a 3G dongle and blog while up a mountain?

I recall seeing a commercial version of that very thing 5 or 6 years ago. I don't recall the company...

But here's one, and Asus also is launching a similar line (with a built-in screen.)

Very similar to the old Tandy Color Computer, or the Commodore, the TI99, the Sinclair ZX80, and many others from the past.

nvideas ion platform will soon be embedded into phones. id say 2 years for it to become mainstream, these phones will be capable of playing 1080P HD dvds flawlessly! and this is comming from someone who dont like nvidea :P the ion platform will revolutionise phones. although nokia have a new phone comming, the nokia N900 and it will have a 1GHz processor, 512 ram expandabe to 1GB using shared memory from the 32GB flash memory bank and will have a 720p screen and a dedicated graphics processor

The company OQO has had it's model 2+ out for years now, with more computing power than the average home desktop, this thing really packs a punch! It has 2 GB of RAM, 300 GB hard drive, 7 hour battery, latest processor, and it all fits in the chest pocket of your shirt.

Could you provide a link?  At some point soon, I'll edit the topic text to include the pointers that have been provided in these comments.  Thanks!


This is the most awesome UMPC (Ultra Mobile Personal Computer) I have ever seen.

I think these goals are unrealistic when compared with modern day technology.

- The smaller something is, the slower it is.

- Lesser room means less heat dissipation, which imply low or substandard duty cycles.

- In any device, the power supply is usually the largest. The computer here would last for at most an hour. Or it could run on AA's. (Yes, that was a joke).

- A projected display is very, very power intensive. Futuristic technologies would have to be further developed (Such as organic LED's) to even come close to this.

The technology we have today; iPhones, and the like, are pretty much state of the art. Man thyself cannot engineer technology increasingly smaller without the help of modern technology. This technology is become increasingly expensive- a direct correalation to the decreasing size. The science is pretty much cosh prohibitive, and limited to the major corporations. And they are, I assure you, state of the art - comparable to military grade (In fact, I believe I saw articles about the military actually using Apple technology.) - and no where near close to this. This may be accurate in the distant future - or even the near future - but defiantly not "today's" era.

None of your first three points are obvious to me.  They may be true, but you need to provide more concrete evidence to support your claims.

- The smaller something is, the slower it is.

How so?  The smaller something is, the less time required for signals to propagate (speed of light).  Decreasing component (feature) size has been precisely the driving force (Moore's Law) behind the continuing increase in computing speed, as well as memory capacity.

- Lesser room means less heat dissipation, which imply low or substandard duty cycles.

The square-cube law says otherwise:  Decreasing volume corresponds precisely to increasing relative surface area, and correspondingly increased heat dissipation through that surface.  If by "lesser room" you mean "packing the same sized macro-components into a smaller box, with less space between them," then you may be correct.

- In any device, the power supply is usually the largest.

To what class of devices are you referring?  Not cars, certainly.  For electronics, this depends significantly on engineering details, not on a priori logic.  In many devices, the battery is substantially smaller than the rest of the object.

Your last paragraph is unfortunately too incoherent for me to really understand your point.  Some of the sentences are tautological: "you can't improve technology without using technology"; while others seem to be just false: "the science is cost prohibitive".  If you can find a way to rephrase what you are trying to say, I would appreciate the opportunity to understand it.

1. You're over thinking. A smaller processor, one with room for less flip-flops, is slower than a larger processor, one that has room for a greater number of flip-flops.

2. Again, over thinking. Less room means less room for heat sinks, and less airflow to move the heat away.

3. I would define "device" as the subject of this article - a computer.

"you can't improve technology without using technology"
This means that technology and technological improvement has become dependent on itself. We have reached the point in development were the human perception - our sense - no longer serve us well enough to continue to develop at the rate of which we are.

"the science is cost prohibitive"
This, I would presume is fairly simple to understand. Try building an iPhone, on your own, without anybody else's tools. If you succeed, you would notice that the cost to build a piece of "state of the art" technology is very, very expensive. Most people, I assume, do not have the millions - yet, billions - of dollars required to develop machinery to create such a sophisticated piece of technology. This is why we leave it up to the companies to build it, and for us, the general population without millions, to buy it.

Wow! Some of those computers are quite small. I might have to build one myself once I save up some money....

does my windows mobile smart phone count?

you would probably need to define "working computer" a bit better because my phone can do most everything i would need my laptop to do...i use my laptop because it's easier to type on

gmjhowe made the same point below, with respect to iPhone/iPod-touch.  In my comment, I brought up the issue of projected keyboard and display precisely because it seems (to me, at least) that the sub-miniature keyboards and teeny displays on smartphones, iPhones, et seq., make them less than useful for real computing tasks. 

Just try to have your company's accountant prepare quarterly reporting spreadsheets using an iPhone display!  Or put together your PowerPoint presentation for those venture capitalists on your Windows Mobile pone.

I definitely recall seeing a network server the size of a deck of cards several years ago.<br /><br />Darned if I can find the reference now...<br /><br />I have found a "computer" smaller than my thumb:<br /><a href="http://www.picotux.com/techdatae.html">The picotux 100 is the world's smallest Linux computer, only slightly larger (35mm×19mm×19mm) than an RJ45 connector. Inside, there is an ARM7 CPU at 55 MHz running uClinux kernel 2.4.27 and Busybox 1.0. Two communication interfaces are provided, 10/100 Mbit half/full duplex Ethernet and a serial port with up to 230.400 baud. Five additional lines can be used for either general input/output or serial handshaking.</a><br /><br />And a "world's smallest Window's PC, this time with a screen and keyboard:<br /><h4><a href="http://www.tomsguide.com/us/is-the-world,review-661.html"><small><big>The world's smallest portable Windows XP computer at 4.9" x .9" x 3.4" (12.5 cm x 2.3 cm x 8.4 cm)</big></small></a></h4><br />

Duh, I'm typing this using my watch.
The hyperspace internet connection is a bit fidgety, and the flash memory is limited to only 16 TB, but it's a computer.
And a lethal laser weapon.
And I'm from the future.

I think it depends on your definition of "working computer". ;)

Not being sufficiently knowledged to answer this I won't try, but, I do love the projected keyboard.

I think custom made devices like iPod touchs, and some of the nokia items come very close. A lot closer than the PDA's of yesteryear did. A lot of people are waiting on an API to allow a person to use the apple bluetooth keyboard with the iPhone. Both the iPod and iPhone boast a 256mb ram, 16-64gb of flash storage, and a 600mhz cpu.<br><br>I know, there is a whole bunch of people who are into this are, often with one handed keyboards hooked upto a small wearable computer, and an inbuilt screen on their cameras.<br>An interesting few areas would be the <a href="http://www.gumstix.com/store/catalog/index.php">gumstix system<a/><br>A more powerful option would be one of the <a href="http://www.mini-itx.com/store/?c=36#specificationsp">Pico ITX Motherboards<a/>, Im sure I read that they could be battery powered, if not, I know one could easily attach a laptop battery.

I agree, in part.  Certainly the iPhone/iPod-touch is an execellent example of a "microcomputer" in the proper sense of the word! 

However, I think that the extremely small built-in display and keyboard, which are both limited to the form-factor of the device, reduce their utility for more intesive tasks.  Jut try writing a long report using an iPhone.

If those devices could be properly connected to a projection keyboard and projection display, that probably solves my challenge, for all practica purposes.

Here is a link for using the keyboard with an iPod.<a href="http://blog.makezine.com/archive/2009/03/external_keyboard_for_iphone_from_o.html"> Keyboard via headphone jack</a><br>You can already use the output on the ipod to display video onto a display, so a projector could easily be 'bolted on'.<br>Just to show how much one can use the ipod, check out this <a href="http://www.youtube.com/watch?v=6GdQmmbO2T4">robot.</a>