Battery-Powered Trebuchet

Yesterday, some friends and I participated in a Project Manus MIT “Let’s Make” event, in which we were given a small kit of parts — an Arduino Uno, a couple breadboards, some potentiometers, batteries, a few sensors — and an hour and a half to build something fun.

Our team was composed entirely of mechanical engineers, so we promptly retreated to the nearest machine shop and built a trebuchet.

A small one. It’s battery-powered.

battery powered trebuchet

A nice little bundle of two 9V and four AA batteries serves as the counterweight, so calling it “battery-powered” is technically correct…which, as the saying goes, is the best kind of correct.


Yes, I made a braided “rope” out of electrical tape to attach the counterweight. It’s not completely authentic — electrical tape was, of course, invented during the 16th-century Siege of Vienna and trebuchets had largely fallen out of favor by the end of the 14th century — but it’s a pretty respectable approximation.


We initially planned to add an Arduino to the trebuchet to power underbelly lighting, but eventually we decided that would destroy the authenticity. So we removed the Arduino with a chisel. It’s important to use the right tool for the job.

Our trebuchet is surprisingly good at flinging small objects like potentiometers short distances. If you’re ever in a position where you need to besiege a sandcastle, this design has considerable merit.