Pi Wars T-38: Attachments part I

The story of this week has been CAD, 3d printing, more CAD, more printing, quick break to insulate the loft, CAD, print - and I'm finally close to having working prototypes for the two big attachments I need for the Zombie Outbreak and Eco Disaster challenges.

In previous years Hitchin Hackspace had kind of a thing for... high energy projectiles.

flinggggg This side towards enemy

In recent years, probably to stop us doing any more silly things like this, the target shooting challenge has needed a bit more finesse, which proved our undoing in 2019's contest: our Nerf gun shot darts plenty fast enough but it wasn't accurate. The Hitchin team was then roundly defeated by the excellent Forest Fighters, who had a much simpler concept for their space invader shooter: a chute that a ball rolls down.

mean green machine Forest Fighters' Shrub Bug. Picture (c) Mark Mellors, https://www.flickr.com/photos/7205519@N08/albums/72157679663827238

Adhering to the KISS principle netted them a very respectable score, and I decided to take a leaf (har har) out of their book in building my own zombie zapper.

more CAD Plagiarism is the sincerest form of flattery

I did want to make one incremental improvement, though: the Forest Fighters' flinger had a single shot capacity and needed reloading on every ball. I figured a simple servo escapement could handle multiple projectiles, and here's how it ended up:

So: with a suitable "barrel" chute in place that ought to do the job with a minimum of reloads. Now my print has just finished on the second attachment I'm building so I'm off to assemble that. There's a sneaky clue in the video...