Two off-the-wall ideas for useful (or at least entertaining) inventions (original to ^z, as far as he knows, both thought of many years ago) — based on shrinking something down a few orders of magnitude:

• micro-machine model railway sets — fabricate a tiny train set on a postage-stamp-sized silicon wafer, using etching and deposition technologies to lay out tracks, crossings, switchyards, etc. The scale is about one millionth of real life. With wee actuators to move 10-micron engines along at a brisk pace of a few millimeters per minute (~60 mph equivalent), a bedside table can conveniently hold a setup to simulate a large county or a small state. View the layout through a stereomicroscope; control it with a small computer.
• directionally-opaque windows — scatter 100-micron sized optically-switchable particles throughout the thickness of a pane of glass or plastic. Turn them black in a correlated pattern, so that their shadows have minimal overlap in selected directions. (Control the particles' opacity electronically, or to block a bright light source use a material that turns dark under direct illumination but not when shaded by a particle in a previous layer.) What you have then resembles a miniaturized set of louvers, aligned so that they attenuate light exponentially in a chosen direction, but only remove a third or so (asymptotically ~1/e) in other orientations. Looking at this directional "glass", you see a black spot centered on the sun and a gray haze in other directions. It's just like a set of tiny electronically-steerable venetian blinds, fitted within the thickness of a window pane.

Two cute concepts derived from scaling optics or mechanics — what are some others?

Tuesday, October 05, 1999 at 06:12:48 (EDT) = 1999-10-05

TopicPersonalHistory - TopicThinking - TopicScience

I believe that the idea of a device like the second item showed up in a Scientific American magazine (It was in one of the Mathematical Games, Metamagical Themas, etc. recreational math columns), where a monk at a fictional monestary was told to build a digital sundial. His trick was like that described above. - RadRob

(correlates: GenderBenders, OrchardOfThoughts, FractalWalls, ...)