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Sharing some project planning phase: A (digital) ELECTRO-MECHANICAL Network
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RJSV:
   Some practical observations:
   Accumulated friction probably will limit the number of series connected units: A string with 30 stages would be efficient, using 4 motors to turn the 30 (virtual rotating motor) addressable outputs.
   Of course, attempting to gain such efficiency does not work, for the other 2 axis, lacking yet another scheme, things (component count) blow up fast, for component counts.  The assumption being, that somewhat, a high component count is tolerable, when using re-cycled plastic 'line source' material, doing 3-D printing. It is the actual DC PM motors that have 'exotic' construction materials, ceramic magnets and other special metals used to make typical toy sized motors.
A 'few' actual motors is OK, but a motor count approaching 48, that's also going to involve driver electronics, say: 8 motor driver channels per driver PC board, that would require 6 PC boards, with processor control, and medium power output transistors (typical 800 mA motor current, each).
   The picture shows some options, for when outputs needed are moderate, such as a five or six output string.  For a 7 output string, only 2 stages are actually needed. PLUS, not discussed in depth, the first stage has its own dedicated motor, for switching all three ('A', 'B' and 'C' columns), and no 'gang-split' so all three rotary signals are simply switched together, as there is no conflict, of having a signal turn off its own path switch.
   After a system has a few stages, it starts to be operated more uniform, but the last stage has to be handled a bit different.
You can surmise: of the six signals being chained, down the serial lines (lines meaning connected rotary paths- analogous to electric wire lines),
Of the six BUS lines, the 'A' column, local, is for enable SELECT.
   The 'B' column, local, is for CANCEL local mode on 'A'.
   The 'C' column, local, is you active stage output, (or 'Client').
Then, also, are the 3 chain outputs, for maintaining the three transmission paths. In other words, the chain signals simply allow transfer stage to stage, (along non-selected stations, transparent or not affecting any components, in current stages as (rotary) signal progresses.
RJSV:
   Things are starting to look good, at least the logic for switching down the line of stations, on the mechanical signal network (digital write-only BUS).
   As picture shows, the timing of 200 mSec. motor pulses (SEL1, 'A', 'B', and 'C' connection columns), is simple. Each movement impulse can be longer, and can even switch polarity, CCW rotation followed by 1 second CW rotation, for example.
   Highlighted is the Stage 4 (rotary) output, simply shown in this case, as a 200 mSec. CW or Clockwise movement, into the user's load or work to do.
   It's a challenge, working out the pipelined series of signals, as there are 3 separate stages being accessed, as including the current stage being output.
   Each new stage adds NO additional addressing requirement, a very helpful situation.
The logic utilizes an early enable, to next stage, tapped by a simple take-off wheel, to clear all switches in current stage.
RJSV:
   Having fleshed out a scheme for getting mechanical 'data' in rotary form, CCW or CW representing data '0' or data '1', here is shown how to read, remotely, from the 'mechanical' network:

   See in the picture, a signal to read a switch position is shown, in normally closed position, very similar to a single pole (electric) relay.  The yellow colored piece will toggle, causing selection of either input wheel.  Shown pushed to the right, this moving toggle piece contacts the (blue colored) wheel for CCW data result: that is a binary '0' representation.
The idea is to interrogate the 'toggle' position and send that back towards the home base. That contains the processor, for motor control, and the 4 small motors in the base unit. So, accessing the last in a string of, say 30 stations, along the series line, and allowing a local switch there to influence the rotary direction, a base unit can recieve the information, of which position the mechanical toggle is resting.
In position shown, a '1' sent to interrogate, will return a '0', implying the position of the sensor switch is 'N.C.' or 'normal closed or un-active'.
   As an alternate, suppose that (yellow colored) toggle is contacting the other wheel set:
Then, the rotation direction of the signal returned will be CW (clockwise).
   Each of how ever many remote switches are used will share that same 'rotary' return signal path, the current active stage being determined by which stage gets that interrogating 'clock', as it were.
RJSV:
(Sorry, this post has the close-up diagram, while last post has the network view).
   In the network, shown is stage 31, as an example.
As seen, an 'interrogation' pulse, (simple rotation, for 200 mSec.), where that pulse gets conducted down the network string of stations and the sensor switch converts that, according to actual switch position.

   As a, perhaps, bizzare example, this could be a mechanical network monitoring a hatch or other deep interior feature, in a nuclear core reactor. OR: perhaps an explosive hazard area, in a factory, where no electric devices can be used. This way, some simple, but crucial data points can be monitored, in a very computer-like manner.
  Not described, are how a base unit would convert such rotary signal, CCW or CW, back to conventional digital (electrical!), but somewhat easy to do that.
RJSV:
   It's a TON of work, laying out parts, and designing.
But a quick couple minutes to assemble. In principal, two BUS signals, A and B, act on each other.
The 'B' signal column is 'GO to Ready',
while 'A' signals: 'STOP Ready state'.
  A general traffic on the BUS is usually A, B, or C and picture shows how each shaft is 'logically' a chain-in chain-out. A fourth signal, shaft, handles local control (select).
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