Hello folks. I don't count as a newbie, but maybe more as an orherbie, since I am a biologist with little tech experience.

Many of my hardware projects fail for lack of funds, time, or friendly support. But I soldier on, a maverick (reluctant) individualist.

I have purchased a Ben Eater "idiot-proof kit", and to that end, will soon be a full fledged "6502-er".

If one searches the forum for the term "optical", one receives 66 hits on the various threads. Probably under 10 or 15 separate topics.

Several of these are my ruminations. But others have expressed interest in 6502 optical implementations.

I had an epiphany a month or two ago. Having acquired some Fiber Optic Image Conduit. ( hereafter, FOICs) and 3 color laser pointers ( RGB), and a few dichroic mirror filters, I resumed where I left off 5 years ago, thinking about how to implement the logic.

Of course one wants some analog to the depletion and enhancement mode transistors familiar to "our little club", via the Balasz schematic and the 6502-visual project.

I envision some very well made dichroic mirrors, external source lasers and FOICs actually integrated into sone sort of wafer-waveguide structures and paths.

One needn't even limit to 2D, as 3D routing of optical signals in waveguides might be quite useful. But let's not get ahead of ourselves as to exact future instantiation. Let's begin with proof of concept.

My epiphany involves one or more of the following elements (1) DMD Texas instruments DLP2000evm, controlled by a raspberry pi or other suitable SBC, (2) Microlens array for fiber coupling from the free space lasers and decoupling to the mirror array and etc (3) rotating nipkow disk for the programming and timing generation, a "slicing" of the large monochromatic, single mode light provided by the humble laser pointer.

Ideally I would not use the light projector as "data input" or even "routing or switching of signals" as I do not want any electricity in my computer except power ( for laser and for nipkow rotating disk).

Ideally, some hack of a CD or DVD might be imagined, with light from the read of the disk directly modulating the output of the lasers that feed the FOIC-6502-and-dichroic-mirror-wafer.

I'll post some of these foolish notions below.

But be aware, 6502 community, I've dreamt up another stinker of an idea, and have started acquiring materials.

Just short the nipkow disks and microlens arrays. I may make the former and have found but not purchased the latter.

Logic available with dichroic mirrors, in their simplest arrangement.

Note there are 6 different devices ; 3 Reflect ONLY one color. 3 Pass ONLY one color. And are named accordingly, Rpass Gpass Bpass and Rref Gref and Bref.

A few other notes on the project. Technically, all combinatorial logic can take place with EITHER ( NOT + AND gates), OR, (NAND gates) OR (XOR? gates. I think?). It's called functional completeness. I think Charles Sanders Peirce was one of the first to describe this. I think he even mentioned electrical implementation in a computing-like device, circa 1880.

But sequential logic ... Sequential circuits, might be trickier. Especially with light. It's hard to trap light in a jar; whereas electricity was literally first trapped in a jar circa Leyden jar and Moeschbroek? and, later, with foil inside the jar and the water out, by John Bevis circa 1740s? 1750s.

Also I'd be curious to know the "maximum path length" a signal takes in a 6502, NMOS or CMOS, from input pin to output.

Like, how many transistors, maximum, a signal passes through from clock cycle to clock cycle.

I was watching a Bill Mensch interview recently and he mentioned a flow diagram that illustrates for each of the 151 valid opcodes, exactly what each op code is doing at each stage of the 7 subdivisions of the full clock cycle. Anybody have a copy of that?

It's important. If I want to use all dichroic mirror sorting/routing for all combinatorial logic, and I have only 99% or 91% efficiency, and a 5 mW signal, 1000 or 3000 reflections might be detrimental. 100 or 200 might be better. I dunno? Could be a "deal-breaker"?

If anybody knows some good info or hints in this id appreciate a "heads up".

My fiber optic Image Conduit vary from 5/64", to 3/32", to 7/64".

I tend to use the 3mm. ( 2.78 mm ; 7/64") and I am pretty certain it is 3000 fiber with 25 micrometer ( um) core.

The microlens array I hope to use is 20 x 20 lenses, I think. At 250 um. spacing. I think. If anybody has a line on a cheap microlens array, PM/DM me.

One sided, convex, one side plano, array.

Here is a picture of one FOIC, reasonably well polished, transmitting a typewriter "e" about an inch upwards. The FOIC is being measured by a English units screw-xhecker.

Each traverse of the signal through the FOIC sees 60% reduction from end to end.

Insertion loss and exit loss might be significant to.

Minor inconsistencies in fiber core placing might necessitate (1) microscope pictures and (b) custom made microlens arrays.

Beam diameter of the laser pointer is probably 3 to 5 mm. I haven't measured it. This should be fine for the microlens array and insertion into the FOIC, or even sectioning by the nipkow disk.

I sort of wished I'd written the date on this? Some time after March or April, but we'll before July 14th, when I got serious about microlenses, DMDs and Nipkow disks.

And I have another diagram, about a week or month after this first one, trying to imagine an implemention of a DLP, and with the specs on the cheapest one.

The one I presently have is ready to be programmed and attached to a raspberry pi and used as a TV wall projector.

The data schematic lists an array of 640 by 360, sub-VGA but still pretty nifty. They tilt from + 11 ° to -15, I think?

It presently outputs light, but I think I might want it to modify my "bulk laser" to feed the initial signal into the microlens array and thus FOIC, and with a second microlens array, bounce it off the dichroic, or several dichroics, and then try to capture some of the logic thus done, with either a CCD/CMOS, or some other means.

For sequential logic, the combinatorial logic done in the first "pass" through the optical system must be held and fed into the second pass.

I am assuming all signals must be boosted again?

But I count this no deficiency. Perhaps CCD can feed right back to DMD and the bright, hot lasers can do their magic on a second pass?

Perhaps this solves the problem of no flip flops or latches in light?

Ok this will be it for tonight. And maybe the week , month, and year. I will post the balazs schematic again, for easy reference.

And mention that I've purchased some #80 push drill, drill bits.

These make a hole 333 um. In diameter, roughly. I assume they can be spaced about on 500 um centers.

But will I go nuts crafting such a thing !

Yup. Nipkow disk.

But it would still be neat.

Of course an optical patterning and etching of a metal light shield would be preferred. Might even be considered efficient.

Maybe I'll just play around with such sizes and apertures until I'm certain diffraction / interference will play no part?

Finally, if I get enough of this material up and running, it might be wise to get some laser diode cans that I can switch on and off with electrical signals, with some regularity. Perhaps controlled by quartz crystals.

Presentation pointers are a poor substitute for research equipment.

Finally, do note that IF a 6502 could be constructed from such apparatus, then it might just as easily scale up to a 6,502 headed 6502, and possibly with good lasers, be run in the pico-femto-atto-second regime !

Chirp it to light speed, my friends !

But first things first. Set up our passive path to bounce the smart signals. And figure out how to catch light in a bottle? For those flip flops and latches.

Dreamin'? Right? Yup. But can't have progress without a dream?

Still living the dream.

"In logic, a functionally complete set of logical connectives or Boolean operators is one which can be used to express all possible truth tables by combining members of the set into a Boolean expression.[1][2] A well-known complete set of connectives is { AND, NOT }, consisting of binary conjunction and negation. Each of the singleton sets { NAND } and { NOR } is functionally complete."~Wikipedia entry, Functional Completeness.