Halloween 3D Printed Surprise Spider

This 3D printing project would look great in a window or hidden by a doorway. When activated, the servo turns a winch, suddenly lowering the spider onto your unsuspecting victim!  

• 360 degree servo.
• BBC microbit.
• A 2xAA battery cage and batteries.
• Terminal block.
• M3 Screws and hex nuts.
• 3D Printer.
• Glue (superglue, hot glue or poly cement will work).
• Sticky Pads or double-sided tape.
• Thread.
• Our design files.

When 3D printing the spider, use support material and a brim in order to avoid the legs coming loose from the print bed. The winch drum shouldn’t need any support material when printed on its side.  

We glued the winch drum to a servo horn then pressed onto the servo. For this, we used superglue although hot glue would work fine as well. As soon as the glue is dry, the spider is attached by the black thread tied and wound around the drum.   

The microbit and servo are held onto the battery cage with double sided sticky pads. Tip: The spider descends slightly faster than it ascends. Because of this, adjust your microbit code so that it always comes back to the same height.

A guide on driving a servo using the BBC micro:bit can be found here.