Alex P. Martinez's home page

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• High school projects
  • Ornithopter
  • Gyrocopter for egg drop contest
  • Two-wheeled skateboard
• Undergraduate projects
  • Ducted model rocket optimization
  • Recursive C program
  • Self-replicating blocks
  • Foam catapult
  • Pizza making machine
  • Finite difference code for heat transfer
  • Simple CFD programs
  • Robot design
• Graduate projects
  • Simple cell model
  • Finite element program for solid mechanics
  • Vorticity-based Navier-Stokes solver
  • Braitenberg vehicle
  • Model of an adaptive growth process
  • Optical tomography using reverse differentiation
  • C++ matrix class for fftw
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  • Laser light going through water
  • Ancient Egypt related artwork
  • Miscellaneous artwork
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Foam Catapult

This was another project we did in a second year design course. The challenge was to design a catapult that could throw a hockey ball the longest distance using two pieces of foam, two pencils and one string. We used SolidWorks ® to make the engineering drawings and those drawing were used by another anonymous team to make the catapult. The other team had to remain anonymous up to the day of the competition so that we couldn't instruct them how to make it; they had to build it with the engineering drawings only. Our team got the longest distance in my class. This allowed us to be the managers of a bigger group for the final competition of the course. Below is a video of the catapult being tested for it’s ultimate yield strength; otherwise known as 'pulling on the string until it breaks' test:

In the video I’m holding a red marker pressing on the string so that I know exactly how far I have to pull the string (minus an arbitrary 10% safety factor) so that I don’t break the catapult in the day of the competition. Chi-Hang (one of the three members in my group) and I also made a presentation about the design of the catapult.