Christmas is a time for giving, and we’re eternally grateful to all-round geek and The Pi Cast guest Richard Hayler for gifting us this Raspberry Pi project: a chocolate-dispensing advent calendar that will only dispense precisely one treat per day.

Hayler, a programme manager with Raspberry Pi who works on the Astro Pi project, created the treat distribution system using one of the popular single board computers, the Build HAT , some Lego components, the 3D RGB Christmas tree kit , and a stash of sweet, sweet candies, plus a bit of Python.
The Build HAT is a collaboration between Lego and Raspberry Pi which enables Lego electronic components, such as motors and sensors, to be used with the popular Python programming language.

A press of a button is all it takes to get this Donkey Kong-like tower of Lego to allow a chocolate to roll, barrel-like, down its sloping paths to the bottom, but it will only work if it hasn’t already handed out a confectionary tidbit that day. If one of the delicious delicacies has already been dispensed, a red light is all you get.

Hayler's YouTube channel reveals previous experiments with Pi-controlled Christmas lights, and a fabulous Lego Apollo 11 display case too.