4 digits, 24hour-notation (military time) mechanical digital clock controlled by micro:bit and only one RC servo motor. Time adjustment from PC is possible via bluetooth.

Tips to make the clock with STL files

• ALL STL files can be printed out without supports. Please arrange them with flat plane facing down.

• Bottom case : front panel should be facing down
• Rectangular axes (servo axis and selector axis) : horizontal
• Display axis (cylinder shaped) : vertical

• The last number of the STL file name is the necessary copies for a single clock. For example, please print four copies of display-4.stl
• Four copies of each digit number (1.STL, 2.STL, etc.) should be printed out with any material of different color (ex. white).
• Generally, large parts should be printed out in light weight (typically two layers, less infill). The inertia of number wheel matters. Contrary, smaller parts should be relatively tough.
• You may need some work (carving, slight bending, etc.) to make the clock working properly.
  • It depends on the preciseness of your printer and slicer settings.
  • To bend PLA parts, use a hair dryer. Please be careful not to overheating.
  • To fix some parts each other, soldering irons or hot bonds are useful.

You need additional parts as follows:

• One SG90 type mini servo (around 2.5USD)
• micro:bit (around 20USD) or your favorite controller circuit.
• Piano ｗire
• silicon oil or grease for lubrication

You can select micro:bit code with or without Bluetooth function.

• With BT version, you can adjust the time from google Chrome browser.
• BT version is a bit unstable due to the less memory problem. Please press buttons on micro:bit slowly or it will reset.
• non-BT version is much more stable. Please use this version if you do not use BT function.
• settime.html is a derivative of the source code in
  https://qiita.com/nakazawaken1/items/4a15480899722a33e8ee

By modifying the code for micro:bit, it can show the time in 12-hour notation, or the other purposes showing a number from 0000 to 9999.