"Pink" pages from color printer

Whoa. I would not have thought of such a division method, my instincts are purely digital when it comes to that sort of things. Of course at the time you did this (60-s?) I did not know what a transistor was, my first attempts to put something together were at the end of the 60-s/early 70-s. Back then my mom worked at a shop for diplomats (real currency only, no Bulgarian) and they had disposable wooden crates of Johnnie Walker... These were my source of material to build things, I built a tape-recorder (player, rather, recording never worked really) using spare parts I could buy for the mechanics... Contributed a lot of noise to the neighbourhood, I must have been 15. But I could not really design the preamp, I just put together things from a book (some Russian book for amateurs IIRC).

As a young kid, I used relays (and score-motors) from pinball machines to make "logic circuits". *Loud*! :>

In high school, graduated to "analog computers" (school district didn't own a digital computer -- just a Wang programmable calculator) which was ... interesting.

I much prefer being able to make really small devices and not have to worry about burnishing contacts, switches, etc.

Yes, it was 1964. At the time my employer (International Computers and Tabulators = ICT) was building commercial computers (

) from discrete transistors, which I had a go at programming in the test bay.

There were interesting early Russian computers too...

My favourite hyper modern sundial has a digital display made possible by additive manufacturing. You can print it on a 3D printer. It has the advantage of the classical sundials that adjustment for daylight saving time is easy. Just rotate it by 15 degrees. eg

brands are available)

I once made a fairly accurate water clock for a lecture demo as the cylinder of revolution of a parabola cast in acrylic. If I had thought about it a little more carefully I would have made a triangular reservoir between two parallel sides instead (like the ancients did).

It beat calibrated candles hands down!

My dad built one from components mostly salvaged from scrap ICL1900 boards TI 74 series ICs with display drivers for the nixie tubes. It was surprising compact although it ran a bit warm to leave on continuously. I reckon it was probably in about 1972-3.

My friend - a very keen amateur astronomer had a digital clock custom built to keep sidereal time when digital LEDs first became available. It even had internal battery backup so it could be moved. It was a bit power hungry though. Had it been a couple of years later using CMOS and LCD rather than TTL and LEDs it would have been a lot easier to use!

My own sidereal clock is based on a PIC 16877 which has just enough pins to bare metal drive a 4 segment LCD display and runs off a standard

32768Hz watch crystal with digital adjustment to get the offset.

These days any mobile phone or tablet has an app to show you the sky, satellite predictions and sidereal time so it is kind of redundant.

If you like interesting time pieces the Corpus Clock in Cambridge UK on King's Parade is well worth seeing. It is a Chronophage with a large scale grasshopper escapement and a very unusual pendulum motion.

It is truly hypnotic to watch. Keeps perfect time but the pendulum motion is not a regular amplitude and the display idiosyncratic.

There is a twin/cousin somewhere that was being made for the Chinese market but the timing of the recession meant that it may not have been completed. It's grasshopper escapement is in the form of a dragon.

It was designed by engineer Dr John Taylor best known as inventor of the bimetallic kettle switch and various other interesting electromechanical devices.

I have a a piece of Tektronix lab equipment which divides by 5 using 3 transistors plus many simple passive components.

Basic principle is that a pulse deposits a glug of charge on a capacitor. The fifth glug raises the voltage above a threshold which causes the capacitor to be discharged and a pulse delivered to the next stage.

That's sufficient to get a 5s period from a 10MHz oscillator. To get the 2ns period, they use several frequency doublers based on nuvistors, stray capacitance and bendable wires forming coupled inductors.

FFI see the manual at

Yeah, I saw that when I was researching sundial ideas. I settled on mine because it handles "after sunset" operation. (the implied "joke")

But the "mechanism" is fixed. A viewer wouldn't wonder how it is adjusted to keep correct time.

E.g., in the kinematic display, the rate of water flowing is the obvious calibration hook. But, you know an open-loop design just wouldn't work. So, the puzzle is how/where the display's status is sensed and how that is fed back to the pump (which obviously must exist to recirculate the water)

For folks accustomed to designing loops, the interesting part would be the huge lag in the loop and the inherent variability of the mechanism (to wind, human intervention, etc.)

I used TTL to convert from the multiplexed output of the clock chip to my individual LEDs. Linear regulator so it got warm. Everything wire-wrapped inside a Lexan case that I'd made to show off it's internals.

Biggest mistake (lack of foresight) was (deliberately) painting the back of the face black -- for a mirror-like finish. I hadn't considered\how much of a PITA it would be to keep clean (fingerprints).

LCD displays are boring. I've thought of salvaging those electromechanical displays that sort of resemble split-flap displays (often used for sporting events to display times/scores VERY LARGE). But, they're relatively noisey so you wouldn't want one indoors.

And, it would just be "yet another numeric display". <yawn>

In school, I had a motorized mini-spotlight that would project a spot across the walls/ceiling as if an indoor sun. It was amusing to anyone who thought about it because it mimicked the Sun's motion -- yet paid no respect to the E-W orientation of its travel ("why does your Sun set in the North?")

[Designs should always mess with peoples' heads -- at different levels. I have a rotary dial telephone -- that generates touch-tones. Simple to make. But, a user encountering it wonders: why the hell would you convert dial-pulses to touch tone instead of just using a pushbutton keypad?]

Any "universal display" is boring. I recall seeing an app that has digits melting into their successors ("Dali clock"). Make a *physical* display that does that and I'll be impressed! But, writing a bit of code to sequence an animation is not really inspiring.

Mechanical. Beyond my abilities. I've resigned myself to simply *designing* my Rube Goldberg -- in CAD -- and requiring someone else to do the actual fabrication. It's sort of a defeatist admission but I don't want to be limited to what *I* can fabricate.

There are enough challenges in my "presentation choices" that I can feel proud of the conceptualization, even if I can't put in the elbow grease to fabricate all of the components.

[Ideally, I wouldn't want a new homeowner to consider it as "trash" and move to disassemble it.]

I think of that as the approach of an architect...

Or any other "designer"/composer.

But, if that's your "norm", then you can rationalize never *doing* anything -- just creating paper. Of course, that's the likely role of a REAL "architect" as the resources and skillsets they would need to erect a building would typically be beyond the means of an *individual*.

That needn't be the case in *all* things!

I've a friend who used to grumble about folks who would *say* "I'm remodeling my home" or "I'm putting on an addition" or "I'm tuning up my car"... when, in fact, they were simply WRITING CHECKS -- and someone ELSE was doing the actual work.

"Well, of course! That's what I *meant*" (but not what you said)

[Instead, describe these actions as "I'm HAVING SOMEONE remodel my home" or "I'm HAVING SOMEONE put on an addition"... to draw attention to the fact that you really aren't *doing* anything beyond deciding that you're willing to pay for that activity! "I've decided to have my house remodeled..."]

There's an element of pride in being able to say I *did* this -- instead of "I paid someone else to do it for me" (that is my lament over having to hire-out the fabrication of the "Rube Goldberg") So, the design has to be heads and shoulders above to minimize that aspect of the "job".

The ultimate is probably a king who "built" a pyramid or a palace!

I've found it pretty common in industry, too. Tales from friends whose boss's claimed to have "done" something -- that, in fact,

*they* did. Always apparent when the boss is tasked with explaining the solution and dons the deer-in-headlights look.

Oooops!