Stepper? Timer, best design for a watch winder

[spstansbury]

I've inherited a nice automatic (self winding) watch and want to put together a winder for when I'm not wearing it.

Requirements:

Rotate the watch in one direction for roughly 5 minutes at roughly 10 rpm, stop for roughly 2 hours.
Rotate the Watch in the other direction for roughly 5 minutes at roughly 10 rpm, stop for roughly 2 hours.
and so on....

I don't need:

Any variable speed control - 10 or so rpm is fine.
Any feedback, servo control, etc.
Any holding torque during the idle period.
Any unnecessary complexity.

I like the idea of scavenging a stepper motor from an old floppy drive.

Can I put together a timing circuit from a 555 or two, with flip-flops, H-bridge controller?

Do I need a microcontroller? I know that it would be straight-forward, but maybe overkill? No background here (I can code, but have not done any PIC stuff).


I'm a novice who's interested in the project to learn the technology, but I could use a few pointers to get going.


Thanks for any input.


Scott.

 

[Sceadwian]

If you want simplicity you should learn more about the specific motion required to wind the watch, you may only have to turn it in one direction but vertically oriented to wind it, in which case you could power it by a simple mini motor geared down to rotate the watch veritally at a few RPM.

 

[Super_voip]

most self winders need to be used once per week at most, and arocking motion is all that would be needed to wind it.. a simple solenoid mech would probably do as a watch on a seesaw(teetertotter) arrangement would present very little moving mass.

 

[ClydeCrashKop]

Remember that mouse trap game? My first thoughts were of a very complicated, Rube Goldberg type machine involving raising marbles to roll down a spiral chute and rock something at the bottom just to wind a watch. HaHa.

Anyway, that sound like real good excuse to learn and play with PICs.
First read this https://www.electro-tech-online.com/threads/pic-newcomers-please-read-upd-0xd1.15035/

I would recommend Nigel’s WinPicProg .
As was recommended here on the micro controllers forum and the first tutorials, the PIC 16F628A for $3.50 with 16 I/O pins, 2 comparators, no crystal or caps or compiler or UV eraser needed is a perfect place to start. I was up and running with lights flashing in a couple of days for $23.50.

 

[spstansbury]

CCK - thanks for the links to the PIC info, that does seem to be the way to go.

Back before PIC's were around, folks used to come up with all kinds of circuits with a handful of 555 timers, flip-flops and decade counters - Rube Goldberg assemblies in their own right, I guess.

In the electromechanical vein, I was thinking of a tall (2') pendulum with the watch mounted on top. I remember an old Popular Electronics article about building a "perpetual pendulum" with electromagnets and photocells keeping it going.


Scott...

 

[blueroomelectronics]

Tamiya makes a 4 speed crank axle that can run on 1.5V to 3V with a 1503:1 gear reduction. That's about 6.5 RPM @ 3V.
It also includes a clutch to keep it from breaking anything.
Normally I'd use a processor but if you want CMOS then a CD4060 with a simple RC clock and a little diode logic on the outputs could run a small H-Bridge like the SN754410 or a reversing relay.
https://www.coolcircuit.com/circuit/timer_4060/
**broken link removed**

 

[ClydeCrashKop]

By the way, 1100, 0110, 0011, 1001 to logic level FETs is all it takes to run a unipolar stepper motor. (With snubbing diodes to stop back EMF).

 

[Nigel Goodwin]

By the way, 1100, 0110, 0011, 1001 to logic level FETs is all it takes to run a unipolar stepper motor. (With snubbing diodes to stop back EMF).

Doesn't need to be that 'complicated', just walk a single '1' along the zero's.