Summary

Want to use GraviTrax as an educational aid to teach digital logic to kids? Want to start your own STEM GraviTrax Kids Club?

Assemble these 3D-printed labels for the GraviTrax launch pad, and you can keep track of Input A, Input B, and Input C. Input C can also be used for a Clock signal marble (for example, to implement a NOT gate), or for a Carry-In Bit from the previous place value when adding multi-bit binary numbers.

For example tracks, lessons, and app codes for teaching digital logic using Gravitrax marble runs, see the "GraviTrax Marble Computers" playlist from The Masked Marble on YouTube: https://www.youtube.com/playlist?list=PLJDGaKsG5JeLVG4KFG8oSwUhOFm3bK4-F

Here is a link to a video showing how to assemble the GraviTrax launch pad input labels:
https://youtu.be/oXbdAXnc6xM

ASSEMBLY INSTRUCTIONS: Print both pieces. Glue the flat side of the base with post to the underside of the top. When completed, the post should face down, and the A, B, and C letters should be facing up on top.

TO use: Press fit the label assembly into the top of a GraviTrax launch pad, by inserting the post into the launch pad's central hole. Press down completely. To remove, use your fingernails to grasp and pull the label while twisting.

PRINTING NOTES:
Design updated to combine the post and the base (what was I thinking printing it in 3 parts??)

Note on the launch pad input top: To print in dual color, in your slicer insert a filament change 2 layers above where the A, B, and C start being printed.