Spook Unsuspecting Passersby with Glen Akins' Automatic Grave Bell

As Glen Akins explains, people in the late 18th and early 19th centuries were obsessed with the possibility of being buried alive. It’s an understandable fear, as the possibility of waking up from a state of unconsciousness, while trapped in a coffin six feet underground is truly terrifying. To help those who were buried, but “not quite dead yet,” a safety coffin was devised with a string and bell apparatus, which allows the buried-alive person to ring a bell outside.

Although legend has it that this setup never actually saved anyone from a literal early grave, it’s still an interesting and spooky historical oddity. For Halloween this year, Akins decided to turn into an awesome Halloween prop with the help of modern electronics. His grave bell system uses a leather strap to ring the bell, and instead of it running to a grave below, it’s hooked up to a servo motor to automate the ringing.

An ultrasonic sensor on the outside measures if person passes by, and reacts by activating the bell for a very spooky effect. Since the sensor used has a 5m range, it takes measurements on powerup to see how far away the next static object is, allowing it to react only when the distance changes (useful if set up indoors). An STM8 microcontroller runs the show, though this isn’t critical. It simply needs to operate at 5V, take in serial signals from the ultrasonic sensor, and output PWM for the servo.

The prop looks like some fun and perhaps it could provide inspiration for your next spooky hack, as it seems that once again October and Halloween is just around the corner!