Bryan Bonahoom's W.O.P.R.

Man met machine during BrickFest 2006 as I, a self-proclaimed tic-tac-toe virtuoso, squared off against Bryan Bonahoom's W.O.P.R. It was a great battle that ended in a draw, but even more impressive was the robot itself.

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."

Category:

Howto & Style

Tags:

• Bryan
• Bonahoom
• W.O.P.R.
• LEGO
• Mindstorms
• NXT
• NXTasy
• robot
• tic
• tac
• toe

[dogdogaaaaa]

the computer cheated = )

[33ecb]

my last name is bonahoom :P

[busfany]

Cool!

[TractionEra]

Joshua- Hello, Doctor Falcon. Do you want to play a game? TractionEra- Lets play Global Thermonuclear Warfare Joshua- How about a nice game of Chess instead? TractionEra- Global Thermonuclear Warfare. Joshua- U.S. or U.S.S.R.? TractionEra- U.S.S.R. Joshua- Accepting Codes. A long drawn out War Games senario later... Joshua- Strange game. It seems the only winning move is to not play at all. TractionEra- How about a nice game of Chess? Ware Games is my favorite movie of all time! :)

[tanyeochian]

if it can play 5 stones game, that would b nice!

[54spiritedwill54]

Thats Awesome!

[brdavis5]

Originally, this grew out of a contest where we had LEGO robots going head-to-head in Tic-Tac-Toe, with no human intervention (and, since we used RCX's, no BT). It was amazing to watch, actually, even if you knew how every game was going to end. I have an RCX version on YT as well... the main difference being that it resets its own pieces as well.

[ronaldmcrae]

Correction to my previous comment. The fourth line should have said "unblocked, open path from sensor to Lego 1x2 light brick".

Also, from a Lego show perspective, it would be neat to see two NXT robots playing against each other on the same board, using bluetooth to synchronize the acivity. But then someone would need to clear the board at the end - or would they, maybe there is a use for those 5*4 trap doors - they could open at the end of play and dump the board. Ah well, back to work.

[ronaldmcrae]

I'm surprised by your comments on the RCX light sensor. Yes it wasn't great but I did get it to distinguish reliably between four colors (RED/WHITE/BLACK/MIRROR TILE) as well as a fifth option "unblocked open to light sensor". This was the arrangement for my RCX Slot Machines at Brickworld 2007 (search you tube). Isn't that enough colors for TIC-TAC-TOE? Of course now once using NXT there is no going back. Everything becomes so much simpler. Watch this space for the Brickworld 2008 models!

[Coastergeekperson04]

What fun is it if you can't win every once in a while :p