Optical Bench REDUX: Digital Switching can have Analog Functions!

[RJSV]

Here is photo, of the lower parts count yard light.

[RJSV]

   Just to be doubly sure, for reader clarity on the commonly known PULSE DETECT circuit, (here done with optical ON-OFF digital signals), pls see photo.
   Substituting an 'inverter' symbol for each Garden Light 'gate' (generic term for logic unit), shows the common electronics circuit symbols, adopted for my garden light collection, on the experiment bench.
Going to the right side of diagram you can see that the final 'gate' acts identical to a TTL setup, in an inverted 'Thevinin equivalent', to a NOR gate; that's all convention.

[RJSV]

A friend here had instructed me, on how to post multiple photos, but now, I can't find that basic instruction, in my PM messages received...
   That last photo posted, showing how a 3 gate line-up would exhibit a slightly longer delay, than the lower signal path shown, having 2 gates.
So, for a brief time, your output gate, doing negative logic AND function, will issue a pulse turn-on, that should (in theory,...sigh..), should last, perhaps 100 nano seconds, until that last upper path gate goes to 'ON' state...THAT should then disable the negative logic AND performed by the very last gate in the
line-up.  That's why I labeled the last delay gate as being a later rise (of led light output), supposedly allowing some short time, to issue a pulse, indicating that a positive or rising edge occured, at the left-side signal input.
   Failed theory, on my part, is OK here, as that's part of the whole learning process, for adapting those little yard lights to switch, like a TTL logic device could.
   One possible explanation, (I gotta get on the 'OSCOPE, in the landlord's electronics bench); it is possible, some extremely brief light pulse IS happening, ...just not visible !!
(I'll be checking for that, lol).
  Another possible switching action detail, is that the tiny increased spacing, gate to gate, creates some analog related delay, as perhaps electronic rise times in each light transmitting gate is increased, not due to distance related light propagation, but due to simple reductions in input intensity, to the solar cell used as light sensor.
Either way, just gonna take some time, and motion.  I have access to a very decent LAB and workbench, and rental (from a Mechanical Engineer, who does Electronic stuff).
Meanwhile, I'm investigating  the whole 'product quality' snaffoo, where those little garden lights got 'dumbed down', this year lasting only into about 9 pm, while older garden lights had more reasonable usefull run times (at least to 1 am).
   Please see photo, showing three 'generations' of these little solar light systems. The bigger unit on left in photo (circa 2010' ish) provided 3.6 volts, wired out to your various LED lamps around the garden.  Then, sometime after about 2015, those independently charged garden lights arrived on market: providing decent running hours, usually past 11 pm, (at least).
Please refer to photo.
Thanks for reading!

[RJSV]

...oh and some more detail, on the yard light switching circuit:
   That series 'resistor'...I've realized, in series with output LED, is actually an INDUCTOR, green colored, and ohm meter showing at '5' ohms...(I've been reluctant to trace the full circuit, until forced to, by the unanticipated switching. (Priority is more with subsystem exploration, such as that Ambient Light A to D conversion.
The digital aspects of that Analog to Digital converter are a simple challenge, to demonstrate ordinary logic processes, (like edge detection), and binary counters, etc, with commonly known Digital to Analog with comparator included.
   But I think, having that inductor in series, does do a voltage 'Buck convert', I'll have to pick at that later.
Big Clive video mentions the 4-pin 'Buck IC' as being:
   'ENA - 6182', the little transistor sized 4 pin package.
   Ultimately, with some work, I've got a nice, NEURON like set-up, for investigating various analog-weighted inputs, to digital switching subsystems.  But I'm willing to go the distance...
   It's the food cost issues, in this wartime, that bug me,
...I can handle engineering some instructional optically based subsystems.  Of course, there's lots of exciting work happening regarding optical physics, Fourier Transform, etc.   My stuff right now, is kinda like the early telegraph exploration, circa 1840's (!!).
Thanks.
Rick B. in Hayward, Ca

[RJSV]

Going gangbusters on some array stuff; I've settled on a kind of 'Ten Segment' arrangement, that has a hexagonal or 'close packed' alternating row, and having
4 rows.
I'm just thinking aloud at this point, but the structure allows flexibility to divide further, into a 5 + 5 where it would be, 2, 3, 2, 3 along the rows.
   For 'processing', there are 5 layers arranged as 'Plates', where each Plate contains 10 gates,...or at least gate positions

[RJSV]

In this view, it shows construction was using some e6000 glue, and a cardboard scrap, as a plate.
   The little lights are the lowest cost,...ONLY one dollar, at $1 .25 each, but I'm getting what I paid for...lowest possible quality.  Plus, they even SPAZZ, like some stupid Zombie movie (not you, Woody)!
Some of the lights go into a 'spastic' blinking, at late night...

[RJSV]

Front view, of a test plate, looks crude, but just checking what that '10 Segment' deal looking like.

[RJSV]

My first mistake, while attempting design, was trying to create stuff 'laterally', when what was needed, was a set of processes that move, in depth.  In this case, it is a set of 5 plates, each having 10 potential gates, or just left blank.
   One example involves a so-called 'Direction Latch', where a set of 4 optical latches will capture and hold the latest motion...that made by the sweep of a flashlight.  The logic is fairly simple. Assuming you've started down, left corner, that first, light responding disk will cause all to reset. Then, each of the 4 sensing angles have a dedicated latch
   An Optical Latch structure is a simple, in-line flip/flop, where layers 1 and 2 form an input chain, while layer 3 has the 'SET' gate, (in the cross-connect), and layer 4 has the 'RESET'gate.
Doing all functions, on each flip/flop, requires going with TWO columns, on the otherwise conventional R-S flipflop.  So, the 50 positions, of the (hypothetical) optical sub-system, are fairly well occupied, sensing and producing indicators, of direction, of flash sweep.

[RJSV]

Picture shows that application, using a generic array.
The application is to trigger on one of the 'sweep' directions, of a hand-held flashlight, and then hold that as an indicator, in a little display.
   The logic is pretty easy; for a start the flashlight (beam) hits the first light sensor, lower left corner.  That will clear all the other latches.
   Next, as the beam is moved, or swept across, each column will be a flip/flop,...responding to any light received, up top, layer #1.  Each of four different angles, of beam travel as the hand moves, are featured.  That is assigned according to the geometry of the placements, of each sensing yard light.
Notice you don't get a 'clean' 45 degrees; rather, that's going to be 41 degrees, approx, but you do get a clean basic 30 degrees and 60° degrees.
   I found that going to a 'depth' oriented logic, rather than wiring possible WITHIN each plate, the depth direction is a bit more challenge.  Generally, each flip/flop needs more than just the one in-line column, just simply for bringing in the SET and the RESET signals.
   Going to a partially wired, and electrically switched LEDs kinda eliminates the spirit of the 'all optical' approach, but...helps move everything along, towards some heavily optical stuff, hopefully.
The 'lateral' direction stuff, keeping within one plate, is very convenient, for including a couple toggle switches, and occasional 6-position rotary select.  Usually, an optical output section gets the most advantage and flexibility.

[RJSV]

This photo shows, schematic for one particular stack of sensing units, where the flip/flop is embedded as an in-line pair of gates, within stack of 5.
You only actually need two cross-connected gates; however another partial column is needed, for the various signals coming into the RS type flip/flop.

[MK14]

A friend here had instructed me, on how to post multiple photos, but now, I can't find that basic instruction, in my PM messages received...

Here is a link, to a post, I made about how to post multiple pictures, in the same post:

https://www.eevblog.com/forum/vintage-computing/cpu-clock-times-mechanical-computer-systems/msg3292962/#msg3292962

[RJSV]

There's a lot to explore, still, before the logic block gets my confidence, but it's interesting.  Biological systems, similar to this, encompass HUNDREDS of nerve cells and connections, and 'partial' weighted inputs. (I get stressed, at 'twenty'.)
   The start of some of this exploration, was with a 'random' sprawl of 15 or so 'gates' (yard lights), where I noticed some LEDs stayed on, but the pattern shifted, when I 'scanned' over the array, with a quick flashlight sweep.  Even more curious; some LEDs, in that random jumble, seemed to want to 'store' or latch and hold, according to what I did, with flashlight sweep.  A lot of that 'accidental' function, tracking direction, seems related to (various) deliberate 'edge detect' schemes.
   Now, a next action, after getting basic directional latching, would be some more logic added, (optically), that will shut down any subsequent latching, by inhibiting the other latches, in a one gate only strategy.
That, in itself, adds a lot of simple bulk, to a '10 by 5' logic block.
   Notice the '10' gates, making up one of the five plates in depth, the so-called '10 gate', refers to the X, Y array in the rough, being alternates, 2, 3, 2, 3 across, you could loosely say it's a '3 X 3' or even '3.1 X 3.1' as a reflection of an (X, Y, Z) structure, having a horizontal 'resolution' of about 2.5, so you could approximate as '2.5 by 4'... by 5 deep.
Sounds silly, maybe, but those numbers give an approximate feel to the (optical) logic block, and what kind of sending 'resolution' is available.

   Those separable plates, BTW, would typically be left out in daylight, for charging up (each individual).

[RJSV]

   This left-to-right ordered signal path has to have more, than just the straight line travel, of a light beam, for instance.  For doing the typical cross-connect, you need to have more options.  (One method just uses 4 gates, or even six gates, all around a circle).
Much of this concern is geometric, or mechanical spacing and positioning of elements.  The wired LED allows more flexibility, for separately doing optimum placements.  One option involves opening up the disk and 'pointing' the LED portion, back 180 degrees from arriving light, (that's hitting the solar cell sensor).
That way, your two LED units will 'point' at each other.
This same thing can be done, with one unit, to create a line up of units going the other way.  Essentially, you can 'take control' of what is 'up' and what is 'down'.  However, things can get complicated, geometrically!
And some configs will work, but detailed analysis might be missed, unless a 'copy' can be had, for a nice display, off to side of actual 'optical logic block', in a
 3-D format, perhaps.

[RJSV]

It's older news now, as signal flow emphasis is now in the 'DEPTH' direction, but here is the basis, as I had been designing 'laterally', or by wiring LEDs and switches within each particular 'plate'.
   I took the 'FPGA' route here, doing a few connections by default, having inverted copies right there, to use. and considering where to place those big, 6 position rotary selectors, for maximum flexibility, where most all things I need can be dialed in, while some extreme cases can be using full breadboard option.
The 6 position (by two layer!) rotary switch, actually, offers TOO MUCH selection variety, but...I won't complain.
   Most of what I'm interested in, along with some analog processing, is involved with edge detection, rising edge (optical signal) and all.

[RJSV]

Starting the day out, (self-employed), reading the various news...record breaking (worst) conditions in the U.S. of all sorts these days.
   But you have to start, simply that, in the face of every day (bad) news.  And there's a ton of good work to be done.  I hope my optical logic circuitry helps inform, and yes; entertain any readers out there!

   'Napkin Holders' make for great ART,...holding the various optical components, there, on the wire frames 'trackway'.  The paint helps reduce any glare reflection, of that chrome wire.

[RJSV]

This picture shows, the use of 7 'gates' for switching and creating a classic EDGE DETECT circuit.  Following the signal path, left to right, that first gate is merely a source, sending in split paths.  The upper path, is far off to the side, (but close), while that tricky arrangement barely works, and had to hand select for best first unit, to send fairly bright and pointed correct direction.  Most fidgety part, was the gate on far end, that acts as a logical AND gate, but both signals must be bright enough.  That is the upper, delayed, INHIBIT signal that will be soon arriving, after light pulse started into the first gate.  The lower signal must travel the 9 inches or so for triggering the final 'NOR' gate there, at right side output end.
   The whole arrangement needs to be indoors, of course, and supplements such as white board walls help.  The 'Output' pulse is very weak, but seems to work, reliably blinking but just only on the 'rising edge' of incoming light that you flash.
These yard lights are very low quality, however...(I don't trust them, beyond basic experimenting).  Plus, that forward operating Edge Detector needs a very precise and 'finicky' layout.  Some of that can be alleviated in doing a bit of re-packaging.

[RJSV]

   Picture shows, packaging option, with opened up units, there can be a 180° degree shift, of general signal path, for doing the 'cross connect' of typical R-S FlipFlop.  Those two opened up unit packages accomplish an entire FlipFlop, kinda amazing, although more is needed, to begin assembling a counter (for controlling an A to D converter, etc.)
   The counter is to use a 'T' type, or 'Toggle type' flipflop.  For the counting action, a logical 'Follower' stage makes a copy, which is then used, backwards or inverted, for the next counter bit state.  This logic is all helped along, by the use of edge-triggering pulses, (which is why so much emphasis, on getting that aspect of AtoD working.)
The split open housing allows direction changes, for layout simplicity.  In the FlipFlop shown, each state is obtained by a '-P' or positive pulse, so to 'SET' the flipflop, for example, you could flash a pulse of light, to the 'RESET' side, of the RS flipflop NOR gate.  That actually acting as a negative-input AND gate, in the flipflop.
   As far as packaging considerations, I'm already wanting to disassociate the LED, and led wires, as the flipflop output, so that a little, auxillary display can show in real time, the states of everything, inside that 3-D labranith of gates.  Idea is, also, to be able to easily pull the assembly of individual plates apart, for doing the daytime - daylight charging.
   Lol, I have to, literally, WALK my 'computer', every morning...oh geez...

[RJSV]

   As the picture shows, one way to implement the Toggle or 'T type' flipflop, the Main f/f is copied, with that simple little action done by 'phase 1' independent pulse, from a sequencer.  That copy, is then circulated around, to input pair, but with intent to reverse the binary value, simply to invert or 'toggle' to other state.
   That's gets me one bit, and that plus another  edge triggered sub-unit,  gets me into 'ripple counter' territory.  Getting into 3-D layout aspects; you get through the 5 layers pretty quick, and using in-line optical gates (seven, I counted), going to the in-line style of layout, is actually fun, like a cross word puzzle...
   I will post that, in a few, but looks like, first glance, would go (layers) 1, 2, 3, 4, and then turn-around at 5.
Then, coming back, other direction on next column, the optical circuit stretches layer 5, to 4, to 3, and to
layer 2.  That's actually perfect,  at least for one of the backwards running signals, as another 180° degree turn around gets you positioned, for the loop around of the 'Copy' bit, with inversion.
   The phase 1 and phase 2 clock pulses originate from 2 separate edge detectors, with square wave. One clock acts, on input 1 rising signal edge, while other will clock on falling edge, all done with light...at least externally.

[RJSV]

   Sure was off-base on this one:
   Picture shows, when yard light is ON, it's getting
plus and minus 1.5 volts, meaning 1.5 across LED forward, and at about 16 khz !
If I'm reading scope right, it is 9 X .5 usec, across one square'ish cycle.  BTW, having HORRIBLE lookin ring.
   Now, when that 'Edge Detect' was placed on scope, it was doing a burst, if those 16 khz cycles, looks like burst of about 5 milli seconds, ON period containing roughly 50% of each cycle.
   Now, I'm pretty convinced, that 4.7 ohm, green 'inductor' looking thing, (is one).

[RJSV]

Good morning!
   An interesting question comes up about sensors, involving LEDs being pulsed.  In the case of these yard and garden lights it is 60 / 40 square wave, 40 % ON, and at 22 khz.  I'm assuming that retains brightness, to human eye, but what about remote sensors, like a photodiode and LED combo, several inches apart.?
The sensor responds to photons, but surely any sensor arrangement would benefit, from a higher ratio of ON to off, or even just using 'DC' type flashlight, having just a simple resistor / switch, rather than pulsed.
   Some older type optical equipment utilized 'choppers' to artificially produce an AC waveform; that way an OP AMP could simply amplify any light input (before measurement or detection).  It could get crazy, though, out there (backyard garden, etc) full of those light sources, all 'vibrating' at 22 khz, while trying to amplify a single one, they would all interfere...?

   At any rate, I figure each 'gate' (yard light) runs at a switching delay equiv to 80 cycles or so, that number obtained from delay time approx 2 mSec.
That's 2 mSec over 5 gates, or 400 uSec per gate. equiv to some 80 cycles of the 60/40 square wave.
The flip flop arrangement works, as well as the (finicky) rising edge triggered circuit.  Probably, giving like 10,000 separate input pulses to it, when using one of the gates as a (hand held) flash, for testing things.
Other logic expected to work, also, generally, which is actually quite weird...

[RJSV]

(still) Massively surprised, at that oscillating / voltage buck circuitry: would maybe see such a circuit, in a more 'upscale' pricey outdoor lighting system, but NOT here, where even the battery has been downshifted, into cheapness...
  I can almost picture a scene, between Factory Production Engineers, and upper management:
   "Can I see (you) CUT another TWO components, for cost savings, across run of, say, 40,000 new units this week?"
   "...Or, how about a cheaper, or smaller battery?..."
   As photo shows, I'm thinking about 'upgrading' that crazy- 15 minutes of life- little battery.
I mean, analyzing the switching response, and speculating on useful ANALOG input properties,  I also generally feel, that the best yard lighting stuff is going to carry folks into the early evening, 9-10 pm, for those days in heat wave, or simple warm summer eve.  These current batch of lights, hardly make it to 8 pm.

[RJSV]

   I'm reviewing the switching details, on using that
 4-Pin IC (for switching control, in each yard light).
A bit mysterious (pls see diagram), as the LED appears to be constantly in series with the inductor, not switched there.  But I believe that's a BUCK CONVERTER, where the LED, on a constant 1.3 V is either a small, negligible leakage, through the otherwise dark (OFF) state, (being below FWD voltage).
Did I get that right ?  A GREEN color, is INDUCTOR,
right ?
   So, if you look to right of LED, is the 4-Pin control IC, and to activate some good light output the IC modulates the pin 1, this to alternate at 222 khz.  That way you get a Buck Voltage increase, each cycle that opens it's switch...Causing inductive surge down thru LED to circuit ground.
That waveform sure does RING...either that or I needed a better scope probe. (Nice old-school Tektronix).
So, (of course when dark), this circuit will keep the LED bright, by the 60% off / 40 % on square wave, at 222 khz.
   My assumption is, that in the setting for evening lighting, it's, maybe, a useit or lose-it scenario...if enough ambient light, from porch, house interior, etc. keeps the garden light OFF, it just leaks a little, through the dark LED, with the Buck Converter not running.
   A little strange, to try to scope out / use multimeter, as the LED seems to always get power.  Plus it seems; any light level to cause 'Switch Off' would, maybe, charge the nmh battery, a minor amount.
   Doesn't matter, if garden light drains out, each night, for the 1 dollar cost of the thing.

[RJSV]

   Great news about that 4-PIN IC Solar LED Driver:
Please also see YouTube, Chris's Workbench (2018).
The IC is called YX 8018 similar to YX 8050.
   The BUCK Voltage BOOSTER will produce approx. 3 V peak to peak or 1.7 V average.  Thanks to Chris's video.
He details some of the options and calculations.  Apparently, selection of different inductors will give you means for setting the LED current.
   Think of the possible uses,... There you have a voltage Dc to Dc converter, a Comparator, for switching at approx .5 volts solar cell output, and basically a logic inverter output, overall.
Great !

[RJSV]

   The example Toy Piano in combination with Solar Light's circuitry is a little wild, in the details.  Essentially put into the place, of one Dome (push button) Switch, you get action when a flashlight is taken away, from the Solar Cell, on the test bench, somewhat an expected result.  To detect any key switch closures there is a periodic scan, of each of the three rows, lasting about 1 mSec. and repeating around the 3 rows (repeats about every 5 mSec.).
The positive side of Solar Cell connects to that Row3 scan, as Row 3, Column 5 is the switch for 'Canned' Song examples to be played: Mary had a Little Lamb, etc.  This Row scan is connected to Solar Cell plus (+) while the Cell negative (-) connects to the Toy's processor input, for column 5.  That way, the Solar Cell negative output provides gnd, or even lower voltage, to the Toy's processor.  Maybe not best idea, but didn't break anything yet.
   The Piano function there is started when your flashlight is pulled away: causing the canned song to start playing (as if you had pressed the appropriate dome switch).  I'm assuming you had given (piano key input) a 'zero', which, when source (flashlight) is pulled, causes the function input to go high state.  This is consistent with original Toy logic, where each positive voltage scan can be switched...giving a positive rising edge, for activating the note or function.
   On Row3 scan output, you can even see a little 'spurious' glitch, in the time slots occupied by ROW 1 and by Row 2, within the 5 mSec. or so scan repetition period.
   But these behavioral things need to be noted on paper, as testing progresses, due to a few oddities:
   1).  If you've connected the Solar Cell 'backwards', and while illuminated (putting out DC voltage),  the mechanical wiggling can cause the function to start up.  (I've tried to visualize the input voltage resulting).
Then, flashing my light at the darn thing can cause one of the piano notes to sound...and this is while the 'canned' song runs, simultaneously!
   I'm not going to figure that part out so easy, maybe just note it in logbook.  But certainly does activate piano stuff, connected either way! 
   Leaving that aside, for a second, readers can appreciate; that's a Drug Store Toy device, that provides a set of 3 clock pulses, for other uses, at about 200 hz repetition rate of the typical type keyboard scan.
   Plus, if any readers wish, a good CD 4020 Ripple Counter can divide the 222 khz oscillator signal, I believe down by 14 divider stages, down to some 89 hz if I did the math correctly.
   Dividing the 200 hz keyboard scan would get even lower, some 200 hz ÷ by 16 k if I estimated that
 CD 4020 correctly.
You would want any addition circuit to have independent power supply, like 3 V etc.

   This description is, so far, only covering use of the dc Solar Cell...Wait till I describe using a full, Solar Light circuit, as drop-in replacement, for simple dome switch. (Later).
Thanks.

[RJSV]

Oops!
   I meant to say, you can harness the Keyboard Scan, to get 3 different periodic pulses, in sequence, at about 200 hz for the repetition rate, of the group.
That's off of the Toy Piano pc board.