The main point of this studio was to use a linear actuator to make various devices, so we decided to make two projects: a catapult and a robotic arm.
The catapult we designed is portable and launches ping-pong balls using springs placed under the arm.
There were 2 catapults in this studio. Both of them had the same idea: to pull down one end of the pivot with a linear actuator, but they had different designs. One catapult tried to use the actuator to pull down quickly, whereas this catapult’s arm is loaded by pulling back a string, compressing the springs. The string has a ball on it, which slided off of the arm when it’s time to launch so it doesn’t interfere. A motor pulls the string backwards until it’s in place, at which point a hook clamps onto the arm, and the string slackens. When it is time to launch, the hook would move backwards a little, and boom.
All of the motors were wired up to an Arduino microcontroller with a remote control card to let us shoot it from afar. The catapult did have some problems, like not shooting very far, and having a high reload time, but with more work, springs, and time, those problems could be solved. For now, however, having a working catapult is reward enough.