NXTasy.org Challenge No. 2 -

“Move the Ball!”

Challenge 2 is now over, and it is time to show some videos of the competitors. The mission, if anyone forgot, was to find and pick a ball placed in a random place inside the test mat black oval, go around the oval twice and put the ball back in place. The original rules page is found here. To test the outcomes, each participant had to submit 3 video files with ball placed at three marked sites, and the robot starting from the same place. The average time gave the final scores of each robot.
This challenge was indeed tough. It tested several robotic ‘proficiencies’ – target identification and location using sensor, line following and dead-reckoning (at least some robots used reckoning to return the ball). We divided the competition into two categories – NXT-G in one, and Robolab/RobotC/LabView/NXC etc. in the other. Prizes, courtesy of mindsensors.com, were 60$ coupons for first place winner at each category and 35$ coupons for second places.

Note: some of the video files are pretty big, so download may take some time on a slow connection.

First, here’s a robot that deserves the title ‘the slowest robot’. This modified TriBot, programmed in NXC, had an average result of about 85 seconds. You can watch the three runs here: video 1, video 2, video 3. Better luck next time Victor!

Next, we have Laurens200 RobotC bot. Laurens found a clever way to overcome the discontinuous oval line near the ‘START’ area. The rules were clear – you can’t modify anything inside the oval. What Laurens did was to add some black tape outside the ‘START’ area, completing the oval. A close-up image is here:

You can watch Laurens bot videos here: video 1, video 2, video 3. Also, the well documented RobotC program is here.

Above you see the robot of MichalisZ. He made his program with NBC, scoring the second place with an average of 31 seconds. His line following was very smooth, and went clockwise ort counter-clockwise depending on the last steering direction in the routine which locates the ball (this extra trouble saves some time, and that was just what he needed to beat Laurens). The videos and program are here: video 1, video 2, video 3, NBC code.

I’ll jump now to the NXT-G category. Here we had only two submissions. One of them, made by Alex, had failed to put back the ball in the test runs, even though Alex claimed it worked when no one was watching… He got the second place, even though his result (28 seconds) was better then 1st place winner (54 seconds) that videoed the complete task. His ball mount was pretty original, standing high above ground. Videos are here: video 1, video 2, video 3. The .rbt file and MyBlocks needed are zipped together here.
The NXT-G category winner was Larry, with an average result of 54 seconds. His videos are here: video 1, video 2, video 3. Code and MyBlocks are zipped here.

Finally, we get to Lren, whose NXC robot finished the mission in an average time of 16 seconds! Apart from efficient and fast line-following and accurate targeting, Lren had done a nice job with the ball caster – it caught the ball even if the positioning wan’t perfect. The videos of Lren are here: video 1, video 2, video 3. The NXC code is here.

Thanks everyone for participating, and see you all (and many others, hopefully) in the next NXTasy.org challenges!

Guy Ziv
NXTasy.org