Hollow Clock 4

June 3rd, 2024 : The New Hollow Clock V is released!

New version of the Hollow Clock is released. Contrary to the former version (Hollow Clock 3), the angle of the hour hand is controlled not mechanically but magnetically.

You need

• Three 8mm x 3mm neodymium (neodym) magnets 
• 28BYJ-48 stepper motor and its driver board 
• Arduino nano 
• 2mm tapping screws (short : 5, long : 1)

Printing

• Print all parts with supplied posture. No support needed.
• Select either case-side-hole.stl or case-rear-hole.stl. The former one is intended to enclose the all of the circuits including Arduino nano and driver board. Please use the latter one if you want to use the other types of micro controllers outside of the clock base.

Assembly

• Remove debris and blobs from the parts well for smooth rotation.
• Please make sure that all axes rotate smoothly before assembly.

Codes

• Please test your circuitry and motor using stepper-test.ino
• Then flash hollow4.ino for the actual use as a clock.

If the engagement of the two bevel gears are too loose, use washer1.stl and washer2.stl to tighten the clearance.

If the square shaft of the worm gear is too loose with the square hole of the bevel gear, please use bevel-gear-small-hole.stl. (zero clearance version)

"hour-hand-5mm-shorter.stl" has been added. The attractive force is relatively weak but still works in my case. Please try it!

Wooden Version

Wooden version made with CNC milling machine. The model is slightly modified (thickness of the outer case is increased) but basically same.