You thought Kasparov vs. Deep Blue was epic?! Well, witness as I, a self-proclaimed tic-tac-toe virtuoso, squared off against Bryan Bonahoom’s W.O.P.R. at last weekend’s BrickFest. It was a great battle that ended in a draw, but even more impressive was the robot itself.

See the video.

In describing the robot, here’s what Bryan told nxtasy.org:

W.O.P.R. is a robot that exploits the advantages of NXT over RCX. I previously constructed an RCX based robot to play Tic-Tac-Toe. Obtaining the accuracy required (1/2 a stud in two directions) to play cubes was very difficult and it required many pieces and sensors. With the NXT, I simply used the built in motor encoders. Additionally, it was difficult to get the required dynamic range out of the RCX light sensor to distinguish between filled cells and empty cells on the board. The led to much more complicated solutions to detect the cubes on the board. The NXT light sensor is able to consistently distinguish between cubes and empty cells.

All of this led to an ability to construct a much simpler robot. I also changed the cube size from 4 studs with the RCX robot to 2 studs. Simpler robot and smaller cubes allowed me to construct a much smaller and portable robot. Additionally, this led to a higher reliability. The WOPR ran through BrickFest without any physical breakdowns. The only time it had difficulty playing consistently was when the batteries were extremely low.

The NXT display also enables the inclusion of instructions to the user on resetting the robot. This allowed WOPR to run unattended. I just wish I had included a game counter in the code.

As a side note: Some of the readers may not be old enough to remember the movie War Games from the early 1980’s. This is where the name of my robot came from. WOPR stands for War Operations Planned Response. If you look at the NXT carefully, you will see that it is named Joshua.