Micromouse is an event where small robot mice solve a 16x16 maze. It began in late 1970s, although there is some indication of events in 1950.

Events are held worldwide, and are most popular in the UK, U.S., Japan, Singapore, India and South Korea.

The maze is made up of a 16 by 16 grid of cells, each 180 mm square with walls 50 mm high. The mice are completely autonomous robots that must find their way from a predetermined starting position to the central area of the maze unaided. The mouse will need to keep track of where it is, discover walls as it explores, map out the maze and detect when it has reached the goal. Having reached the goal, the mouse will typically perform additional searches of the maze until it has found an optimal route from the start to the center. Once the optimal route has been found, the mouse will run that route in the shortest possible time.Mice can run at up to three meters per second, with current world records around 6~7 seconds, depending on the maze design.

Mice can use various searching algorithms. Two of the more popular ones are A* and Bellman-based flood-fill searches.

Left: Distance sensors in operation seen through an IR camera. Right: Robot revisions 3 & 4.

Some videos of the robot in action here!