(Available in HTML at <http://canonical.org/~kragen/wood-pda.html>.)
Polished-Stone Handheld Computers --------------------------------- So I've been thinking about making a handheld computer with the look and feel (shininess, irregularity, weight, seamlessness) of a polished semiprecious stone. One way to do this would be to embed the electronics in polyester resin poured into a mold, with an embedded induction coil for charging, some embedded lead shot for weight, and a dark, but not quite opaque, surface layer to hide the interior except for when it was glowing. Input would probably be piezoelectric, localizing surface taps or using rhythm. (See earlier kragen-tol post [magic boxes and secret knocks][magic].) Output could be through embedded LEDs shining through the surface layer or through audio, especially if you held it against a window. (How much lead shot would you need? Lead has a density of 11.3g/cc, against quartz's 2.6g/cc and [the polyester resin's 1.11g/cc][EP4117], so only 14.6% of the volume would need to be lead to equal quartz's density.) It would be shockproof, waterproof, crushproof, not particularly prone to damage from ESD, and it would feel really good in your hand. Some hard silicone around the outside might improve its thermal conductivity. (There are hard silicone resins with high thermal conductivity, right?) Beatrice suggested that you could use an actual polished semiprecious stone instead; cut out a circle from one side, drill out a cavity underneath, put the electronics inside, pot them with epoxy, replace the circle, wipe off the excess epoxy, and then polish the result. Wood-Block Handheld Computers ----------------------------- Another "everyday object" kind of electronic device case: a block of wood. Some time ago I saw a web page about a wooden clock. It seems to be widely available now; for example, <http://svp.co.uk/products-solo.php?pid=4989&ref=froogle&ci_src=18615224&ci_sku=8028> advertises it for £93.99. It explains: > A totally minimal block of wood with digital numbers floating > across the surface. These clever clocks have a very thin layer of > real maple wood veneer that permits the LEDs to shine through. > > Each one is slightly different due to the natural variation in > wood grain. > > Dimensions: 208 x 90 x 90mm > Weight: 1.2kg Another page says: > TO:CA 'wood' LED clock designed by kouji iwasaki in 2002. this > 'wooden' LED clock won top prize at the asahikawa international > design fair in 2002. A third page says they're actually made of MDF under the maple veneer, and has a photograph of the back that seems to confirm this, and a fourth page says the manufacturer is "Takumi of Japan". I think a handheld computer that looks like a block of wood would be pretty nice too. Something the size of a business card (3.5" x 2", or 89 x 51 mm) but fairly thick (say, 15mm), with veneer on at least one side. The resolution of the display would be limited by the light blurring on the way through the translucent veneer; each spot of light would have a radius on the order of the thickness of the veneer. [Veneers are typically 0.8mm][veneers] but are available as thin as 0.3mm. If spaced 1.6mm apart, you could get almost 1800 pixels in a rectangular array into the business-card size. You could do a little better with a hexagonal array: if the distance from the center of a regular hexagon to the center of one of its sides is r, then the distance to one of its corners is about 1.15r, which is the same as the length of each side; and its area is 1½ * 1.15r * 2r = 3.45r², which is 14% smaller than a square circumscribed around the same size of circle. In the case of r=0.8mm, you'd have 2.2mm² per pixel instead of 2.56, so you'd get about 2000 pixels. But then you'd have to deal with the hexagonal array in your software. 1800 pixels is enough for about 45 letters in a traditional 5x8 single-bit-deep font, which is pretty cramped; my cheap two-year-old US$30 cellphone has something like 65 letters'worth of space on its display. But it's enough to be useful. It's a lot more than any of the under-US-$10 devices I picked up for the "[cheap electronics dissection project][electronics]" in 2006, and they are useful for some things. I don't know how easy or hard it is to populate a PC board with 1800-2000 LEDs. I know I wouldn't want to do it by hand. You could hollow out the middle of a block of wood with just a drill and jigsaw; a keyhole saw or wire saw might work in place of the jigsaw. Cutting all the way through it would be a lot easier than just chiseling out a hollow in one side of the block; then you'd need to put veneer on both sides instead of just one. To add strength and keep it from sounding hollow, you'd probably want to pot the whole interior with epoxy or something. You could have a couple of finishing nails visible on one end if you wanted to charge it through actual electrical contacts rather than with induction. Other Everyday Items -------------------- You could also embed handheld computers in the following: oyster shells; bricks; pens (I suggested this previously on kragen-tol); ceramic tiles; beanbags, pillows, and stuffed animals (like the Chumby and the Furby). References ---------- [EP4117]: http://www.eagerplastics.com/4117.htm "Eager Plastics EP4117" Eager Plastics, aka Eager Polymers, has an "[EP4117][] General Purpose Polyester Laminating Resin" with a density of 1.11 g/cc. [magic]: http://lists.canonical.org/pipermail/kragen-tol/2002-April/000700.html In April 2002, I posted "[magic boxes and secret knocks][magic]" to kragen-tol. [veneers]: http://www.diyinfo.org/wiki/Using_Veneers "an article on DIYinfo.org" The article [Using Veneers][veneers] describes the different kinds of wood veneers available today. [electronics]: http://courageous.murch-sitaker.org/~kragen/electronics/ In 2006 I wrote a web page about my "[cheap electronics dissection project][electronics]", where I bought a bunch of cheap electronics and looked inside them.
