Specs and Constraints: Mousetrap Car 2.0

The main goal of my project is to make a mousetrap car that can run over a long distance (hopefully about 200 feet), so most of the the specs below are set based on this goal.


  1. Functionality: the car must be able to achieve a distance of at least 100 feet.
  2. Friction: in order to achieve my long distance goal, the friction between the wheels and the ground, and between the axles and the body must be minimized (powdered graphite lubricant can be helpful here).
  3. Mechanical advantage: an increase in mechanical advantage will lead to an increase in distance, so the lever arm length must be 20 inches long. This is the optimal length so it can’t be shorter or longer than that.
  4. Aesthetic: The car must exhibit a minimalist aesthetic. This also helps with my goal because the car will be lightweight.
  5. Reusability: After each run, all components must stay intact, and the string must be able to be wrapped around the axel again for another run.


  1. Time: Drilling holes, assembling the wheels and setting up the mousetrap can be more time consuming than I think. I usually procrastinate on assignments but it’d be best if I start doing these early on.
  2. Testing the distance: It will be difficult to find a place with a straight and smooth surface that is at least 200 feet long so I can test out my mousetrap car. Right now I’m planning on testing it on the walkway in front of my house, which is not ideal but it’s an option.
  3. Wrapping the string: This is one of the more crucial step. Based on my previous experience, this step can be pretty easy to mess up so I’d have to be careful and make sure I do it right.
  4. Tolerances: I’ll have to follow every dimensions I set as accurately as possible during the assembly process, because it’ll be troublesome to detach parts that have been superglued to each other.


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3 Comments. Leave new

  • like to get to know you well

  • Valerie Welch
    April 14, 2021 1:28 pm

    Hi Thuc, this is a cool project! Good specifications and constraints! It seems like you’ve figured out the optimal shape and size for things. I also had a suggestion for a flat 200 foot stretch. If you went to a local high school track you could use a straight stretch of the track and have 100 meters to work with. It won’t be as smooth as fresh pavement but it would be free of cracks and obstacles. Good luck with this, I’m interested to see the final results!

  • Hey Thuc,

    I like the mousetrap car design you have, and think you’ve outlined your specs. and constraints well. One suggestion for the test area could be a freshly paved parking lot. This would be pretty flat and void of obstacles, and definitely long enough. I think the minimalist aesthetic makes sense as you want it to be light weight, but could you add things to make it appear more minimalist/aerodynamic. Obviously adding weight would make the car perform worse, but finding a way to hide/ cover the mousetrap could make the car more streamlined and portray the minimalist aesthetic more.


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