Homebuilt relay computer

That sort of mechanism was used in some printing telegraph machines. Decoding from n solenoids to 2^n positions of the typewheel. I have a camera here with an analogue version of this. It combines the positions of the shutter speed/film speed dial, the lens aperture ring, and a dial set to the maximum aperture of the lens, and controls the position of the reference pointer for the exposure meter. Olivetti had a really odd mechanism in the TE300 teleprinter. It used a number of cylinders, with offset holes, each cylinder fitting inside the hole of the next larget one. A system of gears and cltuches rotated each cylinder to 1 of 2 postions half a turn apart depending on the state of each input bit. The position of a follower on the largest cylinder was thus determined by all the bits that corolled the cylinders in that mechanism. Anmd then there's the well-knwon Creed combination head with the stack of disks, each one rotated slghtly by a given input bit, and a set of bellcrank levers that fit round the outside such that a different one drops in place for each combination of positions of the input bits. And the ends of these levers stop the rotation of the type wheel at the right place. Mechancial calculating machines are another set of interesting mechanisms to look at ... -tony