A Noughts & Crosses - 4x4 Tic Tac Toe Robot

Introduction

Tic Tac Toe is a classic board game. Two persons take turn to fill in a 3x3 board. The winner is the first to create a line of the same colour. As the board only has 9 slots, there is no definite strategy to win the game every time. Hence, I extended the game into a 4x4 board in a later version.

Early 2007 during my first year as an undergraduate, I designed my first Tic Tac Toe Robot. Two motors were used to traverse the 3x3 game board, along the XY-axes while another motor is responsible for dropping a game piece onto the board. Since the early Lego motor was designed to rotate in a circular fashion, I used a worm gear, with a moving shaft to transform the rotary motion into a linear motion to push the pieces. A cheap light sensor was used to detect the piece's colour.

This Robot won the First Prize in the Cool Computing Competition 2009 at the University of London. A performance of the robot can be seen here http://www.youtube.com/watch?v=o9LxPQSkcno

A light-weight Noughts & Crosses Robot

I re-designed this robot in the summer of 2010. The game board was fixed this time. The worm gear system was replaced with an infinite conveyor belt. The light sensor was replaced with two colour sensors for faster detection. The whole contraption fits nicely in a 30 cm x 30 cm standard Lego base.

A performance of the newer version can be seen here.