String Shooter

Little one in the loop

A string shooter is a cool physics toy. I was inspired by this great demonstration video by Bruce Yeany, and it turns out they can also be made LARGE with rope! – Zoro Feigl

Minimum viable prototype

This was my first minimum viable prototype 2 cable ties, a packer made of scrap paper. and 2 3D printed wheels wrapped in tape.

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Here is a slow mo video of the Mark 1 working. It does work, but when it when wrong, it would rapidly tangle up a big knot around those wheels.

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Mark 2 adding a trumpet to guide the string into 2 toothed wheels and 3D printed housing, Cad 3D Modelling in Solidworks – my tool of choice 🙂 Here’s me playing with Keyshot rendering.

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The Mark 2 worked well, but with heavier string, those 3V motors were underpowered, even when I ran them at 6v!

Parts ready to 3D print

Here are the parts plated up ready for printing on a Prusa i3. The Prusa is so much better quality than the Makerbots we have at work.

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The latest iteration is the Mark 3, it has bigger motors and a better trumpet, here it is working, each iteration is more reliable than the previous.

This project is ongoing, the next stage will be to understand the variables; String weight, Power/torque/speed and to keep progressing the reliability. Then I have a Kinetic art idea for this to explore…