Vanishing Cheese
A block of cheese "disappears" under the dome, replaced by a small mouse.
This project is based on "Mac N' Cheese" by the ever so talented "gzumwalt."
I wanted to use this in Santa's Shop, so I built a copy. Unfortunately, my construction skills were not sufficient to build a model that could reliably run for a couple hundred hours, so I modified the design to use a linear actuator, electromagnet and Arduino.
The cheese is hollow, so the mouse fits inside and the mouse is glued to the round base. The cheese has three magnets on the bottom and one on the top (hidden inside). The dome has one magnet attached to the upper portion of the dome. If the dome is lowered (and electromagnet off), the magnet on top of the cheese "sticks" to the dome magnet and is lifted up. If the electromagnet is "on," the pull downward is greater than the lift upward and the cheese stays in place.
Supplies
Arduino
DPDT relay board
3mm x 1.5 mm magnets
Wire, solder, screws, 3d printed parts
3mm screws
12 volt dc, 2 amp power supply
The mouse, dome and cheese come from the "Mac N' Cheese" project, so the files can be obtained there.
The other files (design and print) are included here.
The electromagnet fits inside "magnet upper" and "magnet lowera." These fasten together using 3mm screws. Thread the wires through the pole and screw the pole into the magnet housing assembly.
Glue or melt (using soldering iron) the magnet pole to the linear actuator holder.
Fasten the actuator arm to the actuator using a 3mm screw and nut. Tie the dome onto the end using thin wire.
Wire according to the schematic. Load the sketch into the Arduino.
The system operates once every 40 seconds or so. Linear actuators and electromagnets have a "duty cycle," and if they are on too much of the cycle, they will overheat.
Downloads
Enjoy the magic :)