Jam Launcher | Devpost

"Imagine a retail park here"

Inspiration

In The Wrong Trousers, there's a scene at the start of the movie where a slice of toast pops out of a toaster and gets shot with jam automatically. We tried to recreate that.

What it does

In theory, a 2-axis arm automatically aims a tube with jam at toast that has just come out of a modified toaster. In actuality, TBD, depending on how well it falls together in the last hour.

How we built it

To detect the toast, we used OpenCV/Python. We attempted more fancy ML-based methods, but none worked well.
The arm's controller was initially written using PlatformIO/C++, but we had difficulties sending buffers from the detector program. As is obligatory, we rewrote the controller in Rust with Embassy. This was great for the USB/serial controller, but amazingly there aren't any established stepper motor driver libraries (the few that do exist were all done seven years ago and have no chance of compiling now).
To fire the jam, we used a solenoid valve and CO₂ chargers to push jam through some aquarium tubing.

Challenges we ran into

We broke the toaster by putting too many springs on the lever
We went to pets at home and got fish tubing after super glueing the pipes together. At one point the tubing exploded and our ears rang for a while.
A lack of understanding of plumbing and the refusual to purchase plumbing tape.
Toast is a very difficult subject to detect using image segmentation, especially when none of us are good at computer vision
The stepper motor drivers currently smell like burning when we try to use them
- Update: The stepper motor screams for the sweet release of death (but with fearless concurrency)
Apple Maps lead us through two miles of mud "paths" to get to Screwfix, which didn't have the tubing we wanted
The O ring exploded last minute and we had to use a rubber band as a replacement.