DIY a hollow clock

    Hello everyone, some time ago I released a project called DIY Hollow Clock. You can click this link to review it.

    This time I'm going to make an updated version of it where the hour hand is no longer connected to the surrounding circle.

    Supplies

Stepper motor 28BYJ-48 and driver board come with

    Microcomputer (Arduino nano, etc.) controls the stepper motor

    2mm x 10mm self-tapping screws*8

    Grease (high viscosity)

    This clock can be printed with most common printers at 200 x 200mm, except for the decorative part (index.stl, 203 x 203mm). A smaller version (85%) will be added later.

    Step 1: Print the Parts

    The above are the parts that need to be printed.

    Some parts require support.

    Deburring is required. Especially the very small gears (the worm and pinion in the center of the clock) should be very clean.

    Axis.stl download

    Download the main .stl file

    Pointer.stl download

    gear.stl download

    h-gear.stl download

    h-gear1.1x.stl download

    h-hand.stl download

    Download scale.stl

    Minute cover.stl download

    Download minute hand.stl

Motor gear.stl download

    Separate index download for 200mm-printer.stl

    worm gear.stl

    Step 2: Assemble the worm gear

    Plastic soldering with a soldering iron helps connect gear.stl, axis.stl, and worm-gear.stl to each other.

    You can also use some safe glue, such as a two-component epoxy adhesive.

    Fill the center gearbox with viscous grease. Not only will it reduce friction, it will also reduce backlash.

    The backlash of the center gearbox has a big impact on the accuracy of the clock. Choose the better pinion from the two candidates. h-gear1.1x.stl is a little bigger than the original h-gear.stl to suppress backlash.

    Step 3: Assemble the Motor Driver

    If the head of the 2mm self-tapping screw is smaller than the hole for the stepper motor, use a washer or a larger screw.

    Step 4: Detail Adjustment

    To prevent the gear from falling out, flip the fuselage on its side (green in the photo above) and engage the hook on the top.

    Attach the minute cover with three self-tapping screws.

    Step 5: Connect the hour hand

    Attach the hour hand using a medium strength self-tapping screw. It should slide as you adjust the clock.

    Attach hoot and index. It can also fix the axis.

    Step 6: Prepare the Circuit

    Connect ports 4, 5, 6, and 7 to the stepper motor driver.

    Connect VCC (+5V) and GND.

    If you want to package the circuit, print the following parts. It can also be assembled with two 2mm self-tapping screws.

    arduino-case1-button.stl

    arduino-case1.stl

    Arduino-Case2.stl

    Step 7: Flash Program

    Flash the code to the Arduino.

    If your motor is running in the wrong direction, change the order of the numbers in the code to

    The numbers relate to the pins of the Arduino nano (D4 - D7).

    Hollow Clock.ino

    Step 8: Testing and Adjusting

    Because there is a certain amount of play in the gear train, the position of the hour hand will shift left and right. To suppress such problems, insert a soft material such as felt or sponge here to provide weak friction.

    Paint your hands for better visibility. Pigment-based paints are better than dye-based inks, which spread by capillary action.

    You can find some useful information in the comments at https://www.thingiverse.com/thing:5142739

    Step 9: Adjust the time

    Microcomputer reset button one minute in advance

    Fine-tune the position by pressing the reset button while the motor is rotating

    Hour hand can be adjusted by hand (friction-resistant)

Hello everyone, some time ago I released a project called DIY Hollow Clock. You can click this link to review it.

This time I'm going to make an updated version of it where the hour hand is no longer connected to the surrounding circle.

Supplies

Stepper motor 28BYJ-48 and driver board come with

Microcomputer (Arduino nano, etc.) controls the stepper motor

2mm x 10mm self-tapping screws*8

Grease (high viscosity)

This clock can be printed with most common printers at 200 x 200mm, except for the decorative part (index.stl, 203 x 203mm). A smaller version (85%) will be added later.

Step 1: Print the Parts

The above are the parts that need to be printed.

Some parts require support.

Deburring is required. Especially the very small gears (the worm and pinion in the center of the clock) should be very clean.

Axis.stl download

Download the main body .stl

Pointer.stl download

gear.stl download

h-gear.stl download

h-gear1.1x.stl download

h-hand.stl download

Download scale.stl

Minute cover.stl download

Download minute hand.stl

Motor gear.stl download

Separate index download for 200mm-printer.stl

worm gear.stl

Step 2: Assemble the worm gear

Plastic soldering with a soldering iron helps connect gear.stl, axis.stl, and worm-gear.stl to each other.

You can also use some safe glue, such as a two-component epoxy adhesive.

Fill the center gearbox with viscous grease. Not only will it reduce friction, it will also reduce backlash.

The backlash of the center gearbox has a big impact on the accuracy of the clock. Choose the better pinion from the two candidates. h-gear1.1x.stl is a little bigger than the original h-gear.stl to suppress backlash.

Step 3: Assemble the Motor Driver

If the head of the 2mm self-tapping screw is smaller than the hole for the stepper motor, use a washer or a larger screw.

Step 4: Detail Adjustment

To prevent the gear from falling out, flip the fuselage on its side (green in the photo above) and engage the hook on the top.

Attach the minute cover with three self-tapping screws.

Step 5: Connect the hour hand

Attach the hour hand using a medium strength self-tapping screw. It should slide as you adjust the clock.

Attach hoot and index. It can also fix the axis.

Step 6: Prepare the Circuit

Connect ports 4, 5, 6, and 7 to the stepper motor driver.

Connect VCC (+5V) and GND.

If you want to package the circuit, print the following parts. It can also be assembled with two 2mm self-tapping screws.

arduino-case1-button.stl

arduino-case1.stl

Arduino-Case2.stl

Step 7: Flash Program

Flash the code to the Arduino.

If your motor is running in the wrong direction, change the order of the numbers in the code to

The numbers relate to the pins of the Arduino nano (D4 - D7).

Hollow Clock.ino

Step 8: Testing and Adjusting

Because there is a certain amount of play in the gear train, the position of the hour hand will shift left and right. To suppress such problems, insert a soft material such as felt or sponge here to provide weak friction.

Paint your hands for better visibility. Pigment-based paints are better than dye-based inks, which spread by capillary action.

You can find some useful information in the comments at https://www.thingiverse.com/thing:5142739

Step 9: Adjust the time

Microcomputer reset button one minute in advance

Fine-tune the position by pressing the reset button while the motor is rotating

Hour hand can be adjusted by hand (anti-friction)