Josh Meyer and I built this little gizmo for Barbot 2013 and we never properly documented it, perhaps due to hangover issues. Finally getting around to it here though, and you may come see it in action next Sunday at the DNA Lounge Cocktail Robotics Grand Challenge!

Schrödinger's Martini is a robot that mixes a quantum superposition of a wet and a dry Martini. This is exactly analogous to Schrödinger's eponymous feline thought experiment, save that no cats are put at risk.

Image credit: Lenore Edman

Gin in a uranium glass is placed inside a wooden box. (Yes, the glass contains actual uranium salts that give it that green color. Yes, it's only a little radioactive. It glows because UV LEDs excite the fluorescence, not from actual radioactivity though.) After the door is closed, the operator presses a Big Red Button on the top, then a Geiger counter inside the box detects random decay events from the uranium. A microcontroller counts the events in a 30 second period: if there are an even number, a servo automatically pours a jigger of vermouth into the glass; an odd count pours a measure of gin. Because these actions are obscured to external observers, the resulting Martini exists in a quantum superposition¹ of wet and dry which lasts until tasting it collapses the wave function.

Many will find the macroscopic consequences of the Copenhagen Interpretation to be quite intoxicating!

Thanks to Mightyohm for the splendid Geiger counter kit, Lenore for the photo, and Simone for instigation with the original series of Barbot festivals -- may they rest in peace or live in the infamy which they may deserve.

¹ignoring decoherence