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 with 2 cable ties, a packer made of scrap paper and 2 3D printed wheels wrapped in tape.

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

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

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 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 on pause at the moment, 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…