After participating in DC 2008, and only receiving a small “Best Ball Shooting Mechanism” award, my team decided to try again. This year, the game involved picking up balls of different colors, and shooting them over the appropriate opponents wall.
JK Flip Flop II was started in December of 2008, and in May of 2009, had made it past all the rough milestones and was successfully entered into Design Competition 2009!
After 3 seasons, 2 tiebreakers, and 10 rounds, JK Flip Flop II, proud robot of Team Mallet, came away with 1st prize. Among the spoils were $3000, 1 course credit, and 15 minutes of fame.
Our robot navigates using three 100mW lasers. These lasers normally shine on the wall, which is covered with special photoreflective tape. This allows our laser beams to hit the wall, and reflect back exactly to where the laser is, no matter which direction we are facing. This is useful because we can place a phototransistor right next to the laser to pick up the return beam. If a ball is in the way, there will be no return beam, and that is how we can tell if there is a ball there.
After we find the ball, we have a pair of Faulhaber motors with a gearhead attachment that allows us to drive to the ball. We have another motor attached to a bottle brush that sweeps the ball into our hopper. We though the bottle brush was pretty nifty because the flexible brush ends allows us to flex to the contour of the corners of the arena, so we can pick up a ball no matter where it is.
As the ball rolls down the ramp in our hopper, it is stopped by a gate, which is controlled by a servo motor. Servo motors are motors that aren’t too strong or fast, but can turn to an exact angle on command, due to some nifty potentiometer engineering. Also, they sound pretty frikkin sweet, and look real cute (Imagine Wall-E’s arm going up and down, it’s kinda like that…only not as cool).
While in our hopper, the ball is tested for color. We have 3 phototransistors, each with a different color filter, and this can show us the RYB values of the ball. Once we find the color, we aim using an IR phototransistor, and then shoot it with our sweet shooting motor (which was painstakingly crafted by our mechanical engineering teammate for perfect rotation and speed).
