One of the highlights of Caltech’s mechanical engineering undergraduate curriculum is ME72ab: Engineering Design Laboratory. Satisfying the program’s capstone requirement, this group-based class is typically taken in a student’s third year at Caltech. A two-term class in the fall and winter terms, this capstone class allows students to explore the intersection between mechanical designing, manufacturing, and electronics by building robots to compete in new yearly challenges. 

This year’s competition, Apex Cleanup: Summit, Mint, Bank, involved very heavy and robust robots, many pellet-shaped game pieces, and a 4-foot tall pyramid. The main objective of the challenge was to build two robots that could collect pellets from the ground, climb up the 37° incline of the pyramid, and deposit them at the top. Though this may sound simple, it definitely was one of the harder ME72 competitions, as there were a lot of elements to consider when designing our robots. This year, we received a $1200 budget to buy all the materials to build both robots.

ME72 begins in the fall, where we spent the first five weeks going through an iterative design process to determine how we would build our robots. Our team of six students spent a lot of time brainstorming everything for our robot, from how we would design the drivetrain, deciding which motors would provide enough power to drive up the pyramid, and how we would design an intake system to collect and deposit the pellets. With so many elements to this project, we split up priorities and tasks between our group members, with some focusing on the design and CAD (computer-aided design) of the robot, while others worked on the electronics (my main contribution!) and the intake system design. 

The next five weeks of fall term were spent building one of our robots, with the ultimate goal being to climb to the top of the pyramid by the end of term. Our team spent so many hours in Caltech’s machine shop, which contains mills, lathes, 3D printers, and other machining equipment. It was definitely a challenge to finish everything on time, but in the end, we were ultimately able to summit the pyramid!

After our demonstration at the end of fall term, our team realized that we had made some incorrect calculations that would cause issues climbing the pyramid for the real competition in March. Therefore, once winter term started, we ultimately decided to fully rebuild our robot. We redid our calculations, redesigned the dimensions for our robot, and bought new materials. This was definitely a time crunch! Our team had to build two whole robots by the competition at the end of term (including an intake system to pick up the pellets!). 

By the time March rolled around, we were ready to practice driving our robots and make final modifications. Our professor organized a mock competition the week before the real competition for us to practice playing the game–this was really helpful to anticipate what was to come. Additionally, every team gets to choose their team name. We named our team Climb and Punishment (and named each of our robots the same), a reference to the famous novel Crime and Punishment.

The day of the competition was filled with adrenaline and excitement (and some nervousness). It was so amazing to see the efforts of our entire class come together to build so many robots, all with different methods and designs. Many members of the Caltech community also attended and watched the competition, and it was really great to have the support of my non-MechE friends as we competed in this event (which was a culmination of six months of hard work!). 

Though our team didn’t win, we learned so many valuable lessons from taking this class. For example, I knew close to nothing about electronics for robots when I started fall term. However, now I’ve learned so much about Arduinos, wire gauges, soldering, and all sorts of electronic components and methods needed for robotics. I’ve listed some of the most important takeaways below, as well as some tips for anyone considering taking ME72 in future years!

ME72 Tips and Takeaways

• Communication and open-mindedness are key to working in a group.
• Ask for help! If you’re unsure about something, ask the professor, the TAs, or the machine shop managers (Paul and Trent).
• Split up tasks/subteams for the robot. For example, two people could focus on machining parts for the robot, two people could work on the electronics, and two people could design the intake system.
• Manage time wisely in the shop! Time management is crucial when trying to build two robots in a short span of time.
• Have fun! ME72 can be stressful at times, but remember that it should be an enjoyable experience that you participate in with your friends.

If you want to know more about ME72, be sure to check out another blogger’s post from the 2025 competition or see this link to learn more about the 2026 competition!