Mini Watch Cleaner

Meet the Mini Watch Cleaner, a compact, 3D-printed machine designed for cleaning mechanical watch parts. This device features a few crucial components - most notably a continuous servo (geared up for sufficient RPM), an Arduino Pro Mini controller (for reversing spin direction every 5 seconds), and a small 4-digit LED display that shows a countdown and offers simple user interaction through two buttons. Below is an overview of the design, assembly notes, and usage instructions.

• Base & Housing
  • The base is a sturdy, cylindrical piece that attaches directly to a small glass jar measuring approximately 90 mm in height with a 65 mm lid diameter.
  • The housing includes compartments for an Arduino Pro Mini, a continuous servo, the gear assembly, and the small LED display.
  • The design is meant to “screw onto” or clamp down on the jar for a sealed fit when operating the cleaning cycle.
• Motor & Gearing
  • A continuous servo is used as the main driver. It is geared up to ensure an adequate RPM for the cleaning process.
  • A simple gear train sits between the servo output shaft and the basket rotor. The gear train is designed to keep the final cleaning baskets spinning efficiently.
• Top Mount & Baskets
  • On top, there is a rotor or turntable that holds three small baskets for the watch parts.
  • These baskets can be detached or snapped into place to easily load or unload watch components.
  • Print in PETG (or another chemical-resistant material) for all parts that come into contact with isopropanol (the same ones we use to clean the printer plate) to ensure durability.
• Control & UI
  • The Arduino Pro Mini is housed in a small compartment next to the servo, wired up to:
    • The servo for directional control (reverses every 5 seconds).
    • A 4-digit LED display for showing a countdown timer, cycle progress, and user modes.
    • Two buttons provide simple menu navigation and mode selection:
      • Cleaning Mode
      • Rinse Mode
      • Slow Cleaning Mode
  • When you activate Rinse Mode, you can switch to an empty or less filled jar to run the rinse program.

You will need some 3mm bolts. And one of those common 22x7mm ball bearings.

Recommended 3D Printing Settings

• Material:
  • PETG for all parts that contact isopropanol (basket, rotor, any part exposed to fluid).
  • Other non-contact parts (e.g., enclosure or mounts) can be PLA if preferred.
• Layer Height:
  • For mechanical components (gears, rotor): 0.16 mm for smooth operation and minimal post-processing.
• Supports:
  • Use supports where necessary for overhangs (especially for the lid).

Assembly Steps

• Print all the components according to the recommended settings above. Ensure the servo mount and gear attachments print accurately.
• Attach the servo to its dedicated bracket or slot in the main housing. Add the gear from the underside when the servo is inserted.
• Mount the Arduino Pro Mini in its compartment, and route wiring for the servo, buttons, and LED display.
• Install the LED display in the front-facing opening.
• Secure the rotor in the ballbearing.
• Place the basket holder onto the rotor. They should snap and twist in.
• Test fit the assembly onto the jar’s lid. Adjust if necessary to ensure a snug fit (it should be splash-resistant but need not be hermetically sealed).

In images

Insert a 3x35mm bolt into the axel gear.

Insert the ballbearing into the lid.

Place the gear in the ballbearing.

Screw on the lid axel (there is room for a nut if you orient the bolt the other way). It self taps.

Press the servos arm into the big gear (glue if needed). Note, the servo insert should be on the other side.

Insert the servo, without the gear on.

Slide the gear in under and press with a screwdriver or similar to attatch.

Like this.

Fasten the servo with some shorter m3 bolts.

Testfit the jar, don't over tighten!

Fill the baskets with some parts to clean.

Just stack in whatever order into the basket holder.

The basket holder just snaps onto the axel. If needed it can be twisted to fit better.

The twist lock.

OPTIONAL PART

Fasten the pcb holder with a short m3 bolt.

Add your ratnest of pcb. The importat part is that you can controll a servo.

Insert the buttons from the back of the pcb lid.

Slide on, fasten with two longer m3 bolts on the top.

Code & Extras

For the Arduino code that makes all this magic happen (including direction changes and the countdown on the display), head to the project’s code repository here: https://github.com/christoferjh/Mini-Watch-Cleaner

(Warning: the code is as beautiful as a rabid squirrel on roller skates, but hey… It works just fine for this project!)

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