Is it possible to make a gate level digital wrist watch

[Fluffyboii]

Hi,
Ever since I designed and simulated a digital watch with logic gates for one of my electronics classes in university I had this urge to take that design and make it reality with only transistors. Not even logic gates or flip flops. I did find that it is already done my different individuals and it is not an easy feat.

Anyway I am super into digital watches for the past year or so. I simply like telling the precise time at a simple glance and I love the unusual shape and sizes some digital watches have. Today the idea of making my own digital wrist watch got stuck on my mind. Obviously the easiest way to do it would be to get a microprocessor, few small 8 bit displays, rtc module for precise time keeping, slamming all of that in a 3d printed case. Even doing that would be a feat in itself.
Unfortunately using something like an Arduino, taking the Atmega something processor from it feels wrong. People make smartwatches with lots of functionality with those and just simple time keeping with it would make me sad. I could get a less powerful microprocessor and try to code in assembly to torture myself but I am not in that mood.
Using transistor level logic would never fit in a wrist watch form factor, I wonder if using smd versions of logic gate chips, flip flops, multiplexers, etc. would make it possible to fit in a wrist watch or do I need to get counter ICs and other more complex ICs for it to fit. Today most wrist watches that are digital have a small mcu, a quartz crystal with an inductor, few caps and resistors and thats it. Pretty boring and unrepairable.

I am also curious about when something stops being analog. Analog circuits are fascinating. I also want to make a calculator with all solid state components but analog in design. Adding and subtracting with op amps is easy enough but multiplication is difficult Obviously having it all solid state requires using some kind if led display which requires a dac at some point. Can something similar be done with a watch, nearly fully analog except the display. This is bit off topic from my initial wrist watch idea but is it possible to make a watch with a led display that does all the time keeping with an analog circuitry, just for the sake of it. Something like a RC circuit that charges a capacitor until a voltage threshold is passed that the triggers a comparator for example to keep time. I never truly understood when some circuit truly becomes digital.

This is just my random thoughts at 5am.
Edit: I just searched bit more and a microprocessor less watch requires immense amount of logic elements just as I remember that will definitely not fit in a small package unless I use ICs to do most of the hard work.

 

[rjenkinsgb]

I have an original "tuning fork" Bulova that literally hums along, but you can occasionally find those quite cheaply.
The price on those new ones is crazy, but they are technically interesting!

 

[Fluffyboii]

I have an original "tuning fork" Bulova that literally hums along, but you can occasionally find those quite cheaply.
The price on those new ones is crazy, but they are technically interesting!

I checked out the prices of those tuning fork ones on Ebay but the coolest looking "space view" ones were 300+ euros. Maybe one day I get one. Meanwhile I made this coil.

Inside is hollow like I explained yesterday. This produces measly 2mV AC from what I can tell with my multimeter, Even if I seperated the copper strands and connected all of them in series to increase the turn count it would not produce more than 10mV. Absolutely useless like I thought it would be.
I wonder if it is because the magnet orientation is wrong.

I tried with this coil gun coil I wound long ago and a long magnet and it produced 50mV AC when I move it inside of it. Could probably produce 100mV AC if I were to shake the magnet really fast in it. But that solenoid is obviously too big to be anything practical.

Other than that I have these very fragile 5V bare solar panels I bought from China really long ago. They are extremely hard to solder for some reason and break very easily. I wonder if I can intentionally break these from the middle to make them smaller. I doubt it gets any meaningful voltage in indoor lighting though.

Ok after destroying few of these I can say that making a clean cut on these panels is near impossible even though people on videos seem to be able to split these by scoring a clean cut with a ruler and razor then snapping them clean, whenever I tried that panels just exploded randomly. These are 0.5V not 5V. If I can make the panels bit shorter it would fit in a watch form factor but idk how without exploding them. They always cut parallel to the lines but I need the lines to be shorter a bit as well. I guess the length of the lines determine the voltage and the amount of parallel lines determine the current output.

It just does not work for me.

 

[rjenkinsgb]

The coil to magnet orientation is wrong for that to produce anything useful; both the north and south poles are passing the same strand of wire in the same direction, so they cancel out.

I think you would have to use a number of stretched-out coils along the top and bottom of the tube, so the magnet only affected one side of a coil at a time?

 

[Fluffyboii]

The coil to magnet orientation is wrong for that to produce anything useful; both the north and south poles are passing the same strand of wire in the same direction, so they cancel out.

I think you would have to use a number of stretched-out coils along the top and bottom of the tube, so the magnet only affected one side of a coil at a time?

Ah I guessed it was something like that. Thats what I get for randomly making something. I think I would need small multiple coils like you said. A small DC motor with a large swinging weight like with those automatic watches to turn the rotor left and right may make more sense. But all of the DC motors I have are quite long compared to their width.

Even if I make it right it may not produce enough power. What do you think about the solar panels. A non broken cell produces 0.1V under not so bright LED room light. So it is much more promising. Only if I can find a way to break them into smaller pieces without shattering into billion pieces.

 

[rjenkinsgb]

There are also quite a few commercial solar powered watches. you could put a search on ebay with a price limit and see of any non-working ones appear cheaply enough?

For example, quite a number of Casio "G-Shock" and Edifice models have solar power. The cells in the dials on those presumably give enough to charge the supercap or whatever the charge storage cell is?

I have a solar Edifice, that take about eight hours in direct sun for a full charge; though a full charge runs it for around six months. It only has to average about three minutes a day in outdoor sun, or something like an hour in bright indoor light, to keep going. I just have to remember not to store it too long in a dark cupboard!

 

[Fluffyboii]

There are also quite a few commercial solar powered watches. you could put a search on ebay with a price limit and see of any non-working ones appear cheaply enough?

For example, quite a number of Casio "G-Shock" and Edifice models have solar power. The cells in the dials on those presumably give enough to charge the supercap or whatever the charge storage cell is?

I have a solar Edifice, that take about eight hours in direct sun for a full charge; though a full charge runs it for around six months. It only has to average about three minutes a day in outdoor sun, or something like an hour in bright indoor light, to keep going. I just have to remember not to store it too long in a dark cupboard!

I always wonder where the solar panel was in those G shocks. Apperently it was around the LCD, glued to the frame. I wonder how they make such a weird shaped solar panel. I looked a lot for solar watches. Can not find a broken unit in Turkey though since they are rare enough by themselves. My best bet is finding a cheap calculator. But again I have so many of those bare britte solar panels at hand, I do not mind breaking few when trying to cut some.

 

[Fluffyboii]

Got this calculator to steal the solar panel but it turned out to be fake

There is this other real solar panel I removed from my cheap credit card calculator that produces about 2 volts in room lighting.

Can not find a small soler cell for sale but can buy two of these calculators to get them.

 

[netrunner_sw]

The critical question here is "exactly how do you define wrist", in wrist watch?

The clock will be quite large.

Can the clock continue up to the elbow? Maybe continue via band cable to the upper arm and up towards the shoulder?

I'm thinking like this, but with breadboards instead. Assume that you should be able to heat the plastic carefully and bend them to the right shape?

Graphic presentation: Here I think the choice is between actual light bulbs (Las Vegas) or perhaps a flip clock? I think that aesthetically it will be better with a flip clock. Easier to read if you're driving a car, for example.

And ... you will have quite high power consumption. Power supply should reasonably be lead-acid. Now it is perhaps slightly impractical, so the next best option is probably a bandolier with R20 or 18650? Can it be integrated well with the band across the chest?

Although the construction can be quite expensive, you save money on the gym membership and the risk of someone stealing it on the subway is minimal. Just don't try to take it on the plane. It can be difficult to explain.