Team 6: Indiana Jones

Strategy Summary

Indiana Jones was designed to control both its own snakes and that of its opponent. It would intelligently collect and sort as many snakes on the field as it could and remove the opponent's.

Strategy history and detail

Hardware Summary

Mechanics

Electronics

  • 4 LED/phototransistor pairs

Hardware Details

Mechanical Specifications

Drive Train

Two wheel differential drive train with a gear ratio of 75:1. In order to get more power at such a low gear ratio, three motors drove each wheel. Since effective caster wheels that can support weight are extremely challenging to create, we instead used skid plates placed near the front of the robot.

Lifting Mechanism

A conveyor belt driven by a hacked servo lifted balls up to the top of the robot. The belt was spaced far enough to pick up red balls on its own, and rubber bands were wrapped around the treads periodically to catch the smaller greens.

Sorting Mechanism

A lever switch was used to determine when a ball reached the top of the conveyor. Then a red LED and a phototransistor detected the color.

Dropping Mechanism

A conveyor belt (also on a hacked servo) with a mechanism at the end to control dropping.

Dumping Mechanism

A tray attached to a servo to toss opponents' balls over the edge of the playing field.

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Electronic Specifications

Analog Devices gyroscope for driving straight and accurate turns.

A red LED and red-sensitive phototransistor to sort balls.

Three IR LEDs and IR-sensitive phototransistors for determining initial orientation.

A lever switch at the top of the lifting mechanism to determine when to sort.

Another lever switch at the end of the dropping mechanism to determine when a ball was about to be dropped

A front-mounted lever switch to know when a wall has been hit

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Strategy Details and History

Original Strategy

Originally, we wanted to focus on our opponents' balls primarily and deal with our own near the end of the round. We planned to use the RF system to track our opponents' motions and counter them, targeting whichever collection of balls they did not. We would then proceed to move around the field, collecting any balls we could, dumping theirs periodically and dropping ours into the pits.

Unfortunately, we were unable to make the mechanics work, so we moved to a simpler strategy

Final Strategy

Move around the field, collecting any balls possible and dropping any of our own that have been effectively sorted into snake pits.

Performance

Our design was complex, having many mechanical, electrical, and programmatic challenges. While we were able to overcome most of the mechanical challenges, we were left with very little time to deal with the others

We had two major problems that prevented us from being at all functional in the final competition.

First, our robot's pivot point was at the back, so an initial 180 turn during orientation would inevitably force against the wall.

Second, we believe the black and white paint may have been equally reflective of IR light, making orientation a near impossibility. If we had used the phototransistors without the LEDs, we may have had better luck.

Lesson Learned

Reliability and precision count for more than cleverness and complexity.

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