Analog Wristwatch

So I really want to make an analog wristwatch using a microcontroller. This is still in the early planning stages and was wondering if this is doable. Any suggestions would be highly appreciated!

Purpose: to have an analog wristwatch run with electronic components rather than the traditional quartz or wind-up methods. I know it would be easier to just buy a watch or to go digital but I just wanted to try this as a challenge and because I prefer analog watches.

Basic electronics components:

  • Microcontroller and board
  • Quartz oscillator (same concept as traditional quartz watch, I know)
  • Continuous servo

Questions:
Are the above parts available in low-power and small enough size? I am aiming for dimensions of about 40 mm (L) x 40 mm (W) x 15 mm (H) and to be run off of some kind of button battery.
So far, I cannot find a servo small enough...is there a better alternative?
Would a servo or the alternative be precise enough to rotate the same interval over and over for correct timing?

How good are your manufacturing skills? Can you make custom gears? Tiny custom gears?
In my opinion, a servo is not a good solution. You'd have to find a continuously rotating one (hard to do on such small scale), or modify an existing one (even harder).

A stepper can be as accurate as you wish (or in your case, the time keeping device).
Something like this might do the job.
You'll have to make the gears for it, though.

However, if you go down this route, you're already approaching the functional design of a modern wristwatch.

The 15mm thickness is going to be a problem. You have to sqeeze in the RTC, the battery, motor and have room for the casing, the dials and the cover glass.
Good luck.

The mechanical parts are difficult. There are literally centuries of engineering refinement embodied in a cheap watch.

Look at a 'jellyfish' Swatch, where you can see the mechanism. There's nothing that looks like a conventional motor. It has a solenoid coil that gives the mechanism a kick every second. The mechanism is set up so that it will only go forwards by exactly one second, even if the battery is weak or the grease is cold or it's being shaken on a rollercoaster.

It's tempting to try to repurpose the mechanism from an existing watch but it already has all the electronics set up to run off a watch battery so the usual hacker technique of cutting stuff off with a dremel and hot-glueing more stuff on basically stops at step 1: leave the watch alone.

It might be easier to skip the mechanics and draw the watch hands on a small OLED display, like this one from Sparkfun. The normal Arduinos (even Nano or Mini) aren't set up to use the power-saving modes of the Atmel chip. I expect it will be difficult to get more than 24 hours from a watch battery even though the chip is capapble of extremely low power operation.

My manufacturing skills (and tools) are non-existent. I wouldn't be able to make custom gears (at least not without many tries first). Another big reason (besides creativity and challenge) for why I wanted to do this rather than reassemble a watch.

That stepper motor looks like it could do the job! It is possibly small enough. The next challenge would be to have a small enough board and microcontroller. I would probably have to custom order the board for that. I was thinking of one of these microcontrollers: Smart | Connected | Secure | Microchip Technology

Why would I need to make custom gears? Could possibly just have the hands on the axle of the motor, right?

Yeah, might have to go to 20 mm thickness, but that will still be a challenge.

MorganS:
The mechanical parts are difficult. There are literally centuries of engineering refinement embodied in a cheap watch.

Look at a 'jellyfish' Swatch, where you can see the mechanism. There's nothing that looks like a conventional motor. It has a solenoid coil that gives the mechanism a kick every second. The mechanism is set up so that it will only go forwards by exactly one second, even if the battery is weak or the grease is cold or it's being shaken on a rollercoaster.

It's tempting to try to repurpose the mechanism from an existing watch but it already has all the electronics set up to run off a watch battery so the usual hacker technique of cutting stuff off with a dremel and hot-glueing more stuff on basically stops at step 1: leave the watch alone.

It might be easier to skip the mechanics and draw the watch hands on a small OLED display, like this one from Sparkfun. The normal Arduinos (even Nano or Mini) aren't set up to use the power-saving modes of the Atmel chip. I expect it will be difficult to get more than 24 hours from a watch battery even though the chip is capapble of extremely low power operation.

I was hopeful but I guess the technology is unfortunately not there yet. Yeah I might just go for a digital watch instead.

Thanks for the input, guys.

phpbyte:
Why would I need to make custom gears? Could possibly just have the hands on the axle of the motor, right?

Without gears, you can have up to 1 individually moving hand on a single axle. If you put two hands on one axle they'll be spinning together, and watches usually don't operate like that.
You could have two motors (one for minutes, one for hours) and two separate dials. A bit unconventional, but it would serve the purpose of telling time.