David Pride (he of the Pi-driven Connect 4 game along with other wonderful hacks!) has been at it again. In the hope of scaring the begeezus out of trick-or-treaters, he’s hooked up a motorised mechanism to his Pi that will launch a spring-loaded trellis. On top of the trellis is a terrifying ghoul mask. An ultrasonic sensor detects people approaching and the trellis is then activated, with accompanying scary sounds, of course. It runs off batteries making it ‘headless’ (ha-ha). You can read about the build on David’s blog and see a video of it in action below (thanks David for uploading!):