Hey everyone!
It has been awhile. Over the summer, I participated in a camp at Georgia Tech for aspiring engineers.We built quadcopters from a kit made by a GT graduate student, which was very cool . But I have to say the best part of the camp was the challenge that was given to each group: we had to build a racquetball launcher that could compete in contests such as accuracy, range, and speed (maximum balls shot in one minute). The machine had to be set off from a distance and we could not be touching the structure itself when it fired. While there, I learned how to use a laser cutter, a laser engraver, and a water jet, which was a phenomenal experience.
For the project we were given a limited budget which we would use in a materials auction. The auction was a blast, with groups competing for materials and trying to remain under budget. We ended up with two sheets of steel, polypropylene, scrap wood, and, most importantly, an elastic band.
My friend, Alex Lin, who I have worked with before on a UAV, was in the camp with me, and we formed a team consisting of us and two other campers. We decided on a crossbow design using an elastic band. We split up into two groups: the designers and the constructors. Due to my proficiency with 3D modeling, I was one of the designers. I was tasked with the general design of the crossbow, the design of the triggering mechanism, and a stand for the machine. My partner would assemble the pieces, mark the screw points and measurements, and send them on to the other half of our team to put together.
At first, I planned on using the polypropylene as the main component in a structure that would slide and lock together in an elegant method. Unfortunately, the machine that we needed to cut the polypropylene with was not large enough to accommodate our designs. This resulted in a complete scrap of the design. Instead, I designed the body made primarily out of wood. My personal touch to the crossbow was the stand for it and the trigger used to fire it. I designed these completely independent of the rest of the team. We hoped to win the accuracy and distance competitions, so to maximize our chances I designed a system that allowed us to aim our shots fairly consistently. The mechanism is pictured below, and is a sheet of polypropylene cut in a quarter circle with holes cut in it at specific degrees. This allowed us to insert a dowel through the bottom of the crossbow to aim it. We determined the approximate range mathematically, using our rudimentary knowledge of kinetics. Surprisingly, the final range was relatively close to our estimates. This was a great learning experience, as it taught us to be resilient after our first design failed.
Below are some pictures:
Construction:
The competition:
I got my picture made with Buzz:
Checking our distance:
Buzz even decided to show up at the competition to give it a shot!
Our team receiving our awards:
We were even interviewed about our experience at Georgia Tech!
In the end, we ended up winning the accuracy and distance competition as well as The Best Technical Quality Award. I had a lot of fun and learned some useful new skills! It was a great experience!
