From memory, as it's been 'a minute':

Next Time, probably, to start building a prototype... The full write/read and measure/refresh circuit is now simulated with relays, resistors, lightbulbs, switches, and a rotating drum with magnets and reed switches (to sequence through the bulbs, refreshing each). No Silicon, this coulda been built in 1901.

The relay count has gone down *dramatically* since the last sims uploaded (TODO: upload!). Reliability seems surprisingly good.

There's a handy trick could be done to reduce the circuitry-requirements some more: Presently it's necessary to *stop* a refresh of a "1" bulb before switching to the next bulb. Inserting a current-sensing relay in series between the refresh-circuit and the bulb-sequencer/selector switch/drum might do the job. When the selector switch selects the next bulb, it first breaks contact with the previous, current stops flowing, the relay cuts-out, resetting the refresh-circuit for measurement-mode, which as I recall, might work fine if active with no bulb connected. As soon as current flows, the measurement is taken, refreshing begins... all based on the "sequencing" inherent to one relay's actuating causing the next and the next... (no clocking necessary!) Similar to Propagation-Delays in TTL/CMOS, maybe, but since it actually relies on actuation of relays, rather than logic levels which are always "on" in one form or another, there should be near-ziltch as far as intermediate-states during switching/glitching. it's either off or on, and the next stage *cannot* be on until the previous is, and *cannot* remain on when the previous begins to release. It's kinda groovy thinking this way after all the parallel synchronization circuitry necessary for clocked/synchronous systems. Anyhow, an aside.

The current-sensing relay I imagined was surprisingly hard to find. Seems a simple idea: it's not uncommon to find e.g. a 5V reed-relay actuated at 5ma, or thereabouts... 1kohm winding... So, beef up that wire a bit, winding-resistance down to 1ohm... now a 150mA current flows through the winding, dropping a negligible voltage and actuating while 150mA lights my bulb. Somewhere, thereabouts, anyhow. If they can make tiny little solenoids that run off watch batteries, surely a reed switch could be actuated in these, or similar, conditions... And, surely, there are uses for such all around, no? Lots of searching, seriously, lots. It got to the point I was debating whether the winding in earbud-headphones would trigger a reed switch. Eventually *one* result came up... then two, but only two. Allegedly used in land-line phones/faxes/modems to detect when the line is open(?). Well, shit, if that's the use-case, surely at one time they were plentiful! Surely they have a name! Surely if such exists for phone systems, similar must exist for other common systems, in different ratings and specs. Surely they have a name! "current-sensing relay" Exactly as I'd originally thought, returning results *nothing* like I'd originally thought. Still, only two such models found. WTH. Oh well, I know they exist, and they both happen to be spec'd within my needs, I'll continue to ponder its use, here. What else to do but chalk it up to bad search-fu?

Anyhow, another aside was coming up with an edge-triggered D-flip-flop. A few of these, if simple enough, could be used instead of the rotating drum. Maybe more worth it, now, per the last "D'oh!" wherein I realized I'd need switch-contacts for every bulb, as opposed to every *column* as I'd originally thought... 4Pole relays exist, 4 rows handled by each.

So I managed to whittle-down the Master-Slave edge-triggered flip-flop (in the falstad simulator) down from 4 NANDs and 2 inverters down to 2 spst and 2 spdt relays and two resistors... might be feasible. Though 4 per column still seems a bit much, I've other plans for edge-triggered d-ffs, as well. And, still, might be worth pondering, here, when 35 reed switches (and associated magnets/drum-size) come into play (for a single 5x7 character).

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That's all I can think of, at the moment.

Anyhow, fact is, present circumstances aren't particularly favorable to prototyping this system, even at the one-bulb scale. And, further, this was a tangent of a tangent to a prerequisite to continued development of #Floppy-bird, whose parts I do have and is already set-up just awaiting my return.

Spose light-mem can simmer on the back-burner for a while.