Gadgetorium

A large pumpkin with an image of a cartoon robot with a comical expression carved into it. A smaller pumpkin next to it has two metal eyes and round speaker in the place of a mouth.

Jack O'Lantern

Created: 2023-10-29 Updated: 2025-10-30

2025 Edition

This year I choose GIR from Invader Zim for the design. Since the image I used had good separation of the elements, I went with a traditional carve-through technique. I did most of the work with a pumpkin-carving knife from the dollar store. It isn't very sharp at all, and it took some elbow grease to saw through the gourd. However, unlike most kitchen knives, it doesn't get stuck. The initial stab is tricky, but sawing gives pretty good control.

A knife--short, narrow, thick, with two edges featuring different sized sawteeth.

The original firmware was hardcoded to do the eerie pulsing of the Space Kook, and I only slightly modified that for Beetlejuice last year. This year, I overhauled the firmware using some code from Thinko, so that the animation can be synchronized with the audio.

See it in action video(mp4)

2024 Edition

A large pumpkin with an image of Michael Keaton as Beetlejuice carved into it.

Since Beetlejuice Beetlejuice came out this year, I decided I had to try making Beetlejuice as a jack-o-lantern. I used the same techniques as last year, but it was much more difficult to make a photographic image. I used carve-through highlights this time instead of just glowing eyes. The code has been updated to pull random files from a particular folder, quotes from the first Beetlejuice this time.

See it in action video(mp4)

Construction and First Design: 2023

A large pumpkin with an image of a skull in a space helmet carved in relief. A smaller pumpkin next to it has two metal eyes and round speaker in the place of a mouth. A black cable connects the two. A glowing orange image of a skull in a space helmet.

My first Jack O'Lantern since childhood. I used some clay sculpting loops and a hobby knife to carve the image. This carving is in the likeness of the Spooky Space Kook from the classic Scooby Doo episode. I couldn't resist souping it up with electronics: Amber LEDs simulate candle flames, and a proximity sensor triggers a sound clip with synchronized LED animation.

See it in action video(mp4)

The Internals

A capsule from a toy dispenser protects the pair of LEDs. I used two for more brightness, and animating them independently makes the candle flicker more realistic. Some steel fishing weights hold it in place inside the pumpkin. The cable feeds out and plugs into the cable from the other pumpkin. I used an old headphone cable cut in half.

The main action is the smaller pumpkin, made of foam. An Adafruit PropMaker 2040 board is the brain. (The same as my sound effects board project.) It runs off of a Li-Ion battery. An ultrasonic sensor works as the eyes, triggering when something crosses its line of sight at a set distance. A speaker salvaged from an old set of computer speakers produces the sound.

© 2025 Kyle Delaney | Site Map