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A smart BeagleBrick March 29, 2009

Posted by Florian in Devices, GPE, Linux, OpenEmbedded.
Tags: , , , , ,

Some time ago I wrote some lines about the nice combination of projected human interfaces such like the TI PICO projector for visual output and the ‘laser keyboard’ for input. The innovation you can gain from such a combination is a device whose interfaces dimensions can can differ from the dimension of the device quite a lot. After playing around and having an interesting time watching people using these technologies (e.g. at FOSDEM) I finally manged to create a device study combining the components into a single case. It turned out to be more complicated than I thought and the way to a ‘production ready’ device would involve a lot of research and improvement.The main idea was to have something you can touch and try if it can be useful.

But let’s take a look at it first – for now its just a kind of brick with a BeagleBoard and some more components inside.

"The Device" in action

"The Device" in action

From a technical point of view the contruction is quite simple – its just a collection of easy to get components:

  • TI BeagleBoard (Rev. B4 in this case)
  • Celluon CL850 “Laser Keyboard”
  • A tiny USB hub
  • TI PICO projector
  • Some custom USB cables
  • Huawei UMTS modem
  • One Bopla BOS 800 case
  • A small RS-MMC card for the root filesystem

The batteries didn’t fit into the case – the same problem like my GSM evaluation platform I intended to use for connectivity. Instead of this I had to use the Huawei modem but lost an easy to use audio part (I still would like to see these interfaces in some kind of smartphone) and the charger for Li-Ion batteries. The USB connected UMTS modem is advertized to have audio capabilities but there is no Linux support for this feature yet. Another component that caused some headaches is the HDMI cable for the PICO projector: It is thick and its big plugs waste a lot of space in the small case.

I removed the cases of USB hub and keyboard to make them fit into the case. From the BeagleBoard I had to remove the S-Video connector in order to reduce its height.

The current software is way less spectacular than you might think. Its a simple Ångström distribution GPE image built with OpenEmbedded. I had to replace Xorg with Kdrive in order to get the Xrandr extensions working and added some more software for testing such as an additional browser. This is not really the software you wold expect for a modern smart phone but its a good environment to test an uncommon mobile computer.

So what did I find out in the initial tests?

  • It looks very very geek!
  • Its useful to some extend but you need an even surface.
  • The mechanical design needs improvement. This ‘brick’ case is not really flexible and even a better arrangement of components (e.g. projector and keyboard side by side) would save a lot of space on the table.
  • It would be necessary to have a different lense for the projector: You want a wide angle lens to get a large projection area in a short distance drom the device. As you can see in the image the desk space you need is quite high but the image is still small.
  • The power consumption of the projector is a major problem. It is hard to power with batteries and in a plastic case it gets very hot.
  • Someone needs to come up with a clever holder for a sheet of paper to make it a useful screen. Suggestions welcome!
  • If I have the chance to do so I would like to try an improved prototype with a small secondary display, batteries and a keypad.
Typing on the table

Typing on the table

A device I could imagine would be a kind of a stand for a smartphone with built-in projector module. The next generation of projector modules should be small enough for this and comsule less power. The stand would allow the phone to stand upright on the table and provide the keyboard functionality. The advantage of this solution would be that you would not have to carry around the keyboard engine all the time. And because of the orientation of the phone you can get larger ‘screens’ if the projector is in the top end of the phones case. Maybe I should sketch this for the next blog entry… :)

Have a nice time!


1. Rusty - March 30, 2009

A simple stand for the paper could be a ruler with six paperclips. three paperclips taped to the bottom of the ruler, with just a small amount hanging out the edges, allowing you to hook another paperclip to it. lay the ruler down, 2 paper clips attach to the front edge near the ends, and the third attaches to the back edge in the middle. Now the paperclip at the back gets the center of the peice of paper, and the two on the front get the ends of the long edge. It should be a gentle enough curve that the paper doesn’t fold up on you, yet be curved enough that it will mostly stand on it’s own.

Worst case get a piece of card stock for the display, though with a standard sheet of paper you could do backlit displays (flip image left to right)

For a temporary wide angle lens, see if you can make use of one of the lenses in a really cheep pair of binoculars. Optionally, have one of the objective lenses mirrored and then try reflecting off that, it should spread the image out for you, and won’t have the same sort of spectral difraction projecting through the lens will give you.

2. BeagleBrick.. ein Nettop? | nDevil - April 14, 2009

[…] über das DIY-MID auf BeagleBoard-Basis hatten, fiel mir ein, das ich vor ein paar Tagen eine Art Nettop sah, auf einem Blog, das ich vor Urzeiten mal wegen GPE in meinen Feedreader gepackt […]

3. Robert C - January 6, 2011

Years from now one of the big smartphones (ie:iphone) will come equipped with a similar laser keyboard and pico projector built-in and everyone will “eww and ahh” about how genius it is, meanwhile people like us will be wonder what the heck took so long LOL… seem like the tech is there for a reasonable sized phone with these devices built-in or at least a small “dock” with said devices..

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