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Project
There is a competition every year held at the Ocean County College near us. The Lego company has a branch of their toys called Mindstorm. This allows for people to build robots out of legos, rotating motors and different kinds of sensors included, and code them using a simplistic programming style. Teams compete to see how can build the most efficient robot. This year, they allowed for the team to pick their own task to specify their designs for. A video presentation and an in person presentation is to be included. My team, War Machine, consisted of myself and one other person.
Developing and Building
Our final robot was designed to be a children's toy catapult. The prototype that was built was styled after a sort of catapult Nerf gun made out of legos. It's purpose was to inspire younger people to get involved with programming while having fun launching small balls.
During the development of an idea stage, we had a tough time pining down exactly what we wanted to do. A lot of ideas were bouncing around, but we had to go with the most logical option that we would be able to complete in the time we were given. We wanted to create very intricate designs such as a walking robot, a robot that goes up stairs, or a robot that jumps. We didn't trash those ideas completely. The idea of using gears for the legs inspired us to use gears in a different way. This time as a catapult.
When we finally decided on a catapult idea, we started to brainstorm and research into how the robot should be built. A few concepts were put into place. A rotating base allows for movement. Using an ultrasonic sensor can allow the robot to can scan for objects. During the research, we decided to go with a simple catapult with a motor as the fulcrum and power source. We also came across already existing Lego Mindstorm instruction pamphlets that can aid in our own design. The Lego Mindstorm Crane has a rotating base. We decided to add that into our own design. The final robot turned into two parts: the rotating base from the crane design and our own design for the catapult piece.
The model was successful. We used the bottom of the crane, attached a motor onto the back to power the catapult, and a cardboard arm was attached to the motor to hold the projectile. The robot was able to launch a ping pong ball. The model itself did not come without some problems. The motor caused the robot to be off balance. To fix this, we built the motor into the middle of the base rather than the back of it. The spinning base kept getting tangled in the wires. We then changed the rotation to only be in front of the battery instead of all the way around. The catapult needed to go faster in order to launch the ping pong ball. We extended the arm and attached a large gear to the smaller gear. This sped the catapult. The arm could not lock within the motor; it kept falling to the ground. We put gears and other parts in place to catch the arm before it falls to the ground.
Programming
The code itself was composed of four separate parts. The first part scans for objects within the vicinity. The second part stops the rotating base. The third part rotates the motors that spin the catapult arm and launches the ball. The fourth part pulls the arm back. A lot of the programming was tweaking the values of the motors. We needed the motor to go as fast as it could and stop abruptly. It took a lot of testing and tweaking in order to get the robot to produce a wanted outcome.
Presenting
We had to create a video presentation along with a digital one to use for an in person presentation. We had a YouTube video about how our prototype could be used in everyday life that included a voice over. We also created a digital presentation about the design.
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