The STEMFIE Desktop Catapult is perfect for shooting ping-pong balls or crumpled paper. The ball-holding beam moves using the energy stored by two rotor springs. To arm this catapult, you rotate the beam until it locks into place held by the trigger.

You can shoot ping-pong balls into cups or hit and flip the STEMFIE shooting target, which is included in this project.

STEMFIE Catapult SPS 000003 (animation with target) 640

Information  –   Parts list  –   Build plates  –   Downloads  –   Assembly steps  –   Gallery


  • Number of 3D-printed parts: 70
  • Number of buildplates: 3 plates < 160 x 160 mm)
  • Non-printed items: ping-pong ball or one of similar size and weight, such as a ball made of crumpled paper.
  • Tools: Spanner (SPN-TOL-0004) and driver (SPN-TOL-0001)
  • Assembly time: 20 minutes

Parts list

SPS 000001 assembly step0 parts list

Click for larger image

Click the links below to download each individual STL file. You can also download the ready-made build plates.

Build plates

SPS 000001 assembly step0 build plates

Right-click and save the the following build plates (.3mf file format).


You can download the complete file set for this project from this link. The files for 3D printing are available as individual files and as ready-made build plates.

Assembly steps

SPS 000001 assembly step0 tools

SPS 000001 assembly step1

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SPS 000001 assembly step8

SPS 000001 assembly step8


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