Leprechaun Trap (Simple Machines)

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🍀 Leprechaun Trap - St. Patrick's Day Simple Machines Project

A fully functional leprechaun trap designed around the elementary school "simple machines" project. This build incorporates five simple machines working in sequence to catch one unsuspecting leprechaun.

How It Works

The leprechaun follows the "GOLD! THIS WAY!!" sign and steps onto the platform, triggering a chain reaction:

1. Pulley - The leprechaun's weight on the pot of gold pulls a rope through the pulley system, yanking out the wedge
2. Wedge - Holds the marble in place on the ramp until released
3. Incline Plane (marble slide) - The marble rolls down and strikes the lever arm
4. Lever - Launches the leprechaun up
5. Incline Plane (Leprechaun slide) - Guides the Leprechaun straight through a door that shuts behind him. Trapped! 🎩

You can replicate the trap as pictured or devise your own with the components. 

 

There was a decent amount of trial and error involved to get this working reliably - tweaking of the lever placement and where the marble hits the arm (launch angle & distance), getting the right pot platform height and string tension and pulley arm placement to pull the wedge, adjusting the angle of the leprechaun slide, figuring out where walls/rails were needed to guide him in, etc. 

 

It's great learning experience for little ones - not just the simple machines, but the process involved to get all the pieces working together. Just bring a bit of patience and determination. 

What's Included

• Spiral marble slide
• Lever with launch platform
• Pulley with mounted arm
• Marble-holding wedge
• Pot of gold prop with gold coins
• Circular base to glue to the leprechaun's feet
• "GOLD! THIS WAY!!" directional sign

Materials Used

• ¾" steel ball bearing (Amazon link)
• String/twine for pulley rope and rope bridge
• Small twigs for bridge posts and ladder
• Popsicle sticks for bridge planks
• Cardboard & tape for structures, Leprechaun slide, etc.
• Construction paper for DIY springs beneath the pot of gold platform (hidden from view)
• CA glue with accelerator spray (highly recommend this! Dries instantly, so no need to keep things still while glue sets)

All parts printed in PLA.

Credits

My build uses the following community models - go show them some love:

• 🐊 Flexi Baby Crocs - swimming in the river (scaled down, can't remember how much)
• 🍀 Lucky Leprechaun - the victim (scaled to 66%)