Lego Logic
This sounds like a project that I always wanted to do, but never got around to making a serious attempt. A hobbyist in England has built a set of mechanical logic gates out of Legos.
I haven't seen the original site yet, because it appears to be Slashdotted, but the picture I have seen looks a lot like the basic idea I had. The inputs and outputs appear to be Technic rods set to different positions, so the logic gates could be chained together. Internal gearing from the input rods sets the position of the output rod. According to /., the builder has constructed most of the standard logic gates, as well as a clocked flip-flop. What I'd love to see would be a full adder, or more to the point, a series of them put together.
I seem to remember getting my version of this idea from a Scientific American column many moons ago. Full props to this guy for actually getting off his butt and doing it; I wonder what his source of inspiration was?
Update: I just remembered another magazine article from my mis-spent youth: Somebody built a 4-bit binary adder out of dominoes. You knocked over dominoes representing the input bits from two sets of four rows on one end of the layout, and at the other end, dominoes fell onto spring scales with various "1" and "0" markers for the output. I'm thinking this must have been in something like Byte (which once explained how to rebuild a first generation Speak 'n' Spell into a controllable voice synthesizer) or 80 Micro (which published an article on building a TRS-80 interface a Radio Shack toy robot arm).
Damn if I ain't showing my age here...
