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• Button PCB designs

  Theremin Hero • 09/26/2025 at 21:19 • 0 comments

  Figuring out the space available for button PCBs and wiring to the main board requires accurate measurements of the partially assembled LEGO kit. Images of half-finished builds are helpful for rough measurements, but really we need a full 3D model of the build.

  Following a build video that a LEGO reviewer posted, I was able to virtually build the set in the excellent BrickLink Studio software. This then let me export the full 3D model as a .obj file, suitable for inspecting virtually and 3D printing physical size guides.

  Inspecting the model makes it clear that the space available underneath the buttons is barely larger than the buttons themselves. And with the D-pad, there is a rubber gromit that needs to fit through the middle that allows the part to pivot correctly. 

  With all this taken into account, the resulting boards look like this, with a very small margin for error.

  Printing out the PCB designs at 1:1 scale alongside 3D models of the parts they needed to fit into helped give more confidence that everything should fit.
  

• Initial research & feasibility questions

  Theremin Hero • 09/21/2025 at 17:50 • 0 comments

  The information on the internal design of the LEGO kit is currently limited to two images, which don't provide enough information. Contacting the original designer of the LEGO kit may be the best option to gather dimension information.

  Determining the feasibility requires the following questions are be answered:

  What space is made available inside the LEGO kit when the existing cartridge and lenticular screen is removed?

  Is there space under the button mechanism to insert a PCB with membrane conductive pads?

  There seems to be a physical separation between the screen area and the button area. Is it possible to run wires or ribbon cables between these two areas?

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