Step right up and behold Professor Bubbleton’s Breathing Head, a curious apparatus to keep your audience on the edge of their seats. A submerged head rests under theatrical LED illumination sealed inside a clear apothecary jar — until a visitor dares to tap the vessel, at which point the head responds with a sudden stream of bubbles, as though its humours have not fully departed upon beheading.
At the heart of this modern marvel is the Circuit Playground Express, whose onboard accelerometer and NeoPixel light ring make it perfectly suited for sideshow duty. A knock on the jar is detected directly by the board, triggering a timed burst from a hidden air pump while the built-in NeoPixels provide customizable lighting effects. The result is a self-contained illusion that feels uncanny and responsive, without requiring complex wiring or extra sensors.
In this guide, you’ll assemble the apparatus using readily available parts, mount the Circuit Playground Express inside the jar, and configure our simple code to coordinate the tap detection, bubble effect, and lighting. Along the way, you’ll learn how to turn a single gesture into a memorable interaction — the kind that invites onlookers to step closer, tap lightly, and immediately question whether they should have done so at all.
No actual beheading is required for this guide. Our effigy was not harmed in any way. We'll show you how to create this illusion with any head you'd like to submerge -- all you need is a few clear photographs. Or, use our example effigy for instant gratification!
Cable glands will allow you to pass the air tube into the jar.
You'll Also Need
- A plexiglass apothecary jar that's head-sized - I used this one from Amazon
- Photo editing software (if you want to make your own head, or use our example head)
- A printer
- A laminating machine and at least 2-3 laminating sheets
- A drill and 1/2" drill bit (smaller bits help too)
- A fake mustache to hide the air tube
- Some fake hair for the head - using part of a wig works great
- A soldering iron & accessories
- Silicone RTV Adhesive - great for waterproof seals
- Hot Glue Gun
- A pin or awl for poking air holes
- Some EVA foam, wood, or other material to make a base for the jar
Page last edited February 17, 2026
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