Automatic Watches are great because they do not need batteries; but to wind them you have to wear them! This watch winder is capable of winding three automatic watches so they are set to the correct date and time when you are ready to wear them.
The geometry of the watch winder was driven by the spare parts that I had in inventory including a NEMA 17 motor, an Easy Driver, some bearings, 8mm rod, velcro, 3mm machine screws, Arduino Uno, Relay, Fan (cool the driver) and 2020 from an old 3d printer (I don't have room for).
I am still working on this project (which was more challenging than anticipated) so some elements have been refined, and other elements still need to be tuned and refined.
1) To be able to hold watches of various bracelet sizes - the watch holders are spring loaded
2) Noise - I was able to reduce gear noise significantly by having two flange bearings each end shaft. The original design was going to have side bearings to keep the gears compressed. The cantilever design works well with double bearings on each shaft, which eliminates play in the gears.
3) Gearing itself - the original design had stand alone gears - I integrated the gears into the watch holder
4) Where to place the electronics - the electronics were originally in a separate project box; the electronics are now integrated into the unit. The tray was a large single print which covered the extent of my Rostock Max Bed; the majority of the prints were made on a Flashforge creator pro.
5) Keep the stepper unenergized when idle (added a relay module)
6) Dissipate stepper heat (used a fan and a heat sink)
7) Some watches wind clockwise, some counterclockwise, some unidirectionally (script reverses)
8) Printable with little support (all but electronics tray)
9) Standoffs were originally built into the electronics tray
1) Lid for electronics box - three part now enclosed.
2) Rotary Encoder Programming - If you look at the program you will find that the rotary encoder script has a bug in it. The rotary encoders increment upwards but they don't go down (I am only executing the else part of the statements)
3) Replace some PLA parts with ABS parts for strength.
4) Replace a bad rotary encoder
5) Consider a direct gear reduced motor as opposed to a stepper (I have a 3rpm motor in stock @ 12v)
6) Find the sweet spot between "winding" and "sleeping"
8mm rod x 2
ATmega328P CH340G UNO R3 Board
12v power supply 1-2 amps
2020 - 300mm x 3
Female 2.1x5.5mm DC Power Plug Jack Adapter Connector for CCTV
Male Pin Dupont Connector 2.54mm Pitch (used for + - bus)
Dupont Jumper wire
8mm Bore Diameter KFL08 FL08 Pillow Block x 4
KY-040 Rotary Encoder Module x 2
compression springs x 9
Various 3mm machine screws
Various 3mm metal screws