Designed and Constructed by Rory Foster, Raudel Rodriguez, and Joshua Soong
The Harvester was designed and programmed to be both a "passive" and "active" ball collector and its goal was to drop a ball into the "lava island" scoring pit. The two rotating arms scoop up balls into the holding area, and a gate in the back released balls from a ramp to fall either into the scoring cup or onto the ground, depending on team color.
Design and Implementation
Drive train and Motors: We used 2 motors driving 2 wheels in a differential drive train, with a slider in the front for support. The gear ratio for each wheel was 90:1.
Harvesting Arms: Both arms were powered by 1 motor, with 90:1 gear ratio. The wheels on the arms allowed the robot to pick up balls more easily than static, non-moving arms.
Holding Area/Ball Gate: The gate was made up of 2 servos, which rotated out to allow balls to fall from a ramp onto the cup or ground.
Sensors: We had 2 distance sensors behind each rotating arm, to detect when a ball was in optimal range to be picked up by the arms, as well as stop the robot from running into walls in front of it. There were 2 side bump sensors used to wall-follow. There were 3 rear bump sensors, 2 to detect walls and 1 to detect the scoring cup. We had 3 color sensors on the bottom to detect starting orientation and for line following. Finally, 1 color sensor was used above the ball holding gate to detect the color of the balls picked up.
software The software was written in IC. We used a library of functions to control the motors and read values off the sensors. The approach used when coding was to abstract away movements and sensor reads so that we could focus more on the robots strategy. A mess of variables were declared that set tolerances for color detection, sensor and motor ports, and other run-time specific values.
We lost the qualifying round, because our robot could not found its orientation, and lost the second round because our robot failed to line follow.
Overall Record: 2 Losses.
Start Early! Procrastination will only ruin your last 96 hours before qualifying
A defensive strategy will generally win the contest, although drones are harder to make.
Conserve legos - you get less than you think.
Make 2 battery packs in the beginning - you will need them for sure.