Want to build a Cheap Watch Winder?

Every where I look, there are many people asking, sourcing, sharing, discussing, swearing, advertising, debating, commenting and lamenting about cheap watch winders in the web. How exactly is cheap? I would think it really depends on how much an individual person is willing to pay for the watch winder. The other thing that would hinder them is the “perceived value” of a watch winder. To really understand “cheap”, just try building one yourself. There will certainly be issues now or later with a poorly designed unit.

To make my point, let’s begin to make a real simple cheapo watch winder!

Basically, a watch winder consist of the following: -

• The Housing


• Electronic circuits


• The motor (rotor)


• A watch holder


• Power adaptor or batteries (including the battery holder)


• Lots of imagination, patience and luck.
  

The Circuit
I would like to start with the electronics as this is the engine that will drive the motor intermittently to rotate your watches. Only short intervals are required.

All watch winder manufacturer seems to have some sort of “turn-rest” intervals of various timings. There isn’t a standard to follow so you’ll have to create your own.

To have the motor “turn and rest”, use an Astable circuit which will turn ON the motor for a certain “X” time, then turn OFF for a certain “Y” time.

Here’s my suggestion on a basic watch winder circuit which should do the job.

Once I’ve tested the circuit, I should be able to insert values for each part.

The Winding Sequence
There are so many winding sequences for each brand so you must attempt to have your own for this project. To begin, take a look at the type of motor available. Not any type but one which has a gear-head working at a low dc voltage, preferably with a low rpm.

I’ve got a spare 6Vdc motor rotating at 50rpm. This means that I can safely use 4 dry cells. Don’t worry about the high motor RPM as it only requires to make one turn. That’s where your circuit control comes in.

Next, check to see what TPD and which rotational direction your watch requires.

Example, a Rolex winds bi-directionally and require a minimum of 650~800TPD to remain wound. I got this information from a comprehensive database in a website.

Push the TPD a little higher to compensate for “loss turns” if and when your battery drains. Say, between 800 ~ 900TPD should be fine then; or thereabouts.

To determine the On-Off sequence, you have to make some simple calculations.

To save your time, here’s what I think is the best solution.

If I can get the motor to turn 1 rotation every 1.6 minutes, this would equate to about 900 turns per day.

- Divide 1440 minutes (24hrs) by 1.6 = 900TPD

If you want 800TPD, then your motor has to turn 1 rotation every 1.8 minutes.

- Divide 1440 minutes by 1.8 = 800TPD


Referring to the circuit, this means that the ON time (value of R3) has to give just 1 turn for the motor. The OFF time (R2) has to logically be such that the ON and OFF time totals 1.6 minutes. Since I won’t be precise using discrete parts and I can’t control capacitor leakage in my circuit, my timings would be as close as I can get to have this sequence going.

With this “turn-rest” sequence, there’s no way it’ll overstress the winding mechanism inside your watch. I’m confident it’ll keep it wound.

Since my own watch winds bi-directionally, I could have it turn CW today and then CCW tomorrow to give it a healthy “exercise”. What’s more important is that I keep the TPD controlled.

Labels: d.i.y., homemade watch winder