[Tim's] ghoul in the box project has all the elements of a classic Halloween prop. He built it for last year’s display but we’re sure it will be a perennial favorite.
As the name implies, it’s modeled after a Jack-in-the-box toy. Fittingly, it’s decorated with bright, happy colors and includes a crank on the right side of the box. But you don’t need any man-power to make it work. Hidden in the red circle at the center of the front panel is a motion sensor. Walk in front of the box and one of two modes will be triggered. The crank may start up and a happy rendition of Pop Goes the Weasel plays. But as it nears the end of the song the tempo slows and the pitch drops as if running out of steam. It’s perfect foreshadowing for the vigorous bursting forth of the ghoul inside.
The demo after the break gives you a look at the operation, as well as the components used in the build.