Pneumatic Cannon

When my classmate Jaden approached me about helping him build a giant air cannon for our end-of-year physics project, I simply couldn’t say no. Jaden started CAD-ing the cannon itself while I got to work designing a wooden frame. It had to be affordable, strong, portable, and allow for smooth tilting. After what felt like too many trips to the hardware store, some funding from River Dell High School (thanks, Mr. Pepe), and late nights in my garage, we had a functioning pneumatic cannon and a stable wooden base.

But we didn’t stop there. I wanted this project to be automated. I found a motor I had lying around from the Tennis Ball Machine project, got my hands on a DC PWM motor driver and an accelerometer, 3D-printed a pulley, hooked it all up to an Arduino, and we achieved elevation control. But that still wasn’t enough. I wanted it to be seamless to use. So, I got an Arduino touchscreen shield and wrote a custom object-oriented graphics/UI framework from scratch. The screen displays different modes and options, has a numpad for entering parameters, and includes a live-updating angle readout.

Still, that wasn’t enough. We wanted to input our target displacements into the machine and have a “ballistics calculator” determine the correct launch angle given the projectile mass and air-drag parameters. So, I implemented an onboard numerical-integration-based algorithm that simulates the flight path with Newtonian drag and iteratively hones in on the optimal elevation angle.

In the end, it was all worth it because we secured the non-existent title of the most impressive AP Physics project in RD history.