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




< 160 x 160 mm

ping-pong ball or similar size and weight, such as a ball made of crumpled paper. 20 minutes

Spanner (SPN-TOL-0004)

Driver (SPN-TOL-0001)


Parts list


SPS 000001 assembly step0 parts list

Click for a larger image.

Download the STEMFIE files below by right-clicking on a link and saving it on your computer. You can also download the ready-made build plates.

Build plates

SPS 000001 assembly step0 build plates

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


The files for this and several other STEMFIE projects are available from the central web file repository. Also, if you prefer to have the files synchronized to your computer, consider subscribing to the STEMFIE cloud repositories. For instance, you can clone the STEMFIE GitHub File Repository to your local hard drive and get all updates when you synchronize. 

Assembly steps

SPS 000001 assembly step0 tools

SPS 000001 assembly step1

SPS 000001 assembly step2

SPS 000001 assembly step3

SPS 000001 assembly step4

SPS 000001 assembly step5

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SPS 000001 assembly step8

SPS 000001 assembly step8

SPS 000001 assembly step8


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