For this project, I began with a tutorial I found here on Instructables: Arduino-Controlled Catapult . This was a great instructable to start with as I am not familiar with Arduino projects and this is my first attempt. The instructable includes some good quality pictures, a short video of the catapult's performance, a detailed list of parts, techniques, a copy of the circuit layout, and the program that runs the Arduino. These tools were very helpful in providing a starting point and helping to create this awesome project.
To be clear, I'm still working out many of the kinks in this project. It has the potential to grow and become a more refined piece, but this is mostly a work-in-progress.
Here is a video of my first attempt at using the catapult in its prototype phase.