Marble Sorter

Marble Sorter From Above	Gate System
Secondary Channel	Storage System

Overview

“The National Recreation Park Association (NRPA) has asked your team to develop a solution to a growing problem in their parks. The association has placed dumpsters for recyclable material throughout the parks. They have a sorting facility; however, they need the device that will sort the recyclable material.” -Problem 3.3.1 Design Problem: The Marble Sorter. We were tasked with creating a machine for separating recyclable materials which sorts 3 different types of marbles. The purpose of this fabricated scenario is to introduce a real-life problem which needs to be resolved in a timely and cost efficient manor, putting our skills to the test which have otherwise been strictly used for abstract practice, into a project which will help strengthen our problem solving skills.

We have worked with vex equipment extensively this year with many different projects including the winch design project, and the rube Goldberg machine, each of which required the members of our group to band together and think outside of the box to not only come up with a design, but to also an improvement on that design every day to ensure a well built, efficient final machine. These skills described above were needed to ensure the success of our machine in terms of efficiency (cost, time, etc.) as well as in terms of reliability to solve the problem at hand multiple times with minimal failure.

Conclusion

Our sorter did not succeed in sorting the fifteen marbles, which had 3 different colors. Instead our machine sorted 3 out of 15 marbles correctly in 10 seconds on the second and most successful of the two tries. Despite sorting these marbles in less than two minutes we did not sort all of the marbles.

The problem came with our coding of the 2-wire motor, which allowed the movement of the channel that separated cups, which ideally would have directed the marbles into one of the three cups. In hindsight, if we had an opportunity to change the steps we took to crating the marble sorter we would definitely have started programming sooner as we could have gotten the speeds of the 2-wire for the separation, the servo positions for the gates, and the 14

light sensor values more precisely recorded, which in turn would have helped immensely on the day of testing. Throughout the testing the structure of the sorter seemed pretty solid due to the alterations made post construction (see Post Selection Modifications above), as the problems occurred mostly in the software o the machine.

The budget aspect of the project tripped us up a bit as we expected to blow through the $50,000 budget very quickly if we weren’t careful. We didn’t come anywhere near going over budget (see in Appendix A). Looking back we actually were over cautious with the budget and purchasing supplies because we didn’t account for supplies running out (we actually had to strike a deal with another group for the most important pieces of our machine, the servos, see Appendix C). We were also naïve about programming aspect in correlation with the budget. Since the rental was $1,000 per day we agreed as a group on the very first day that we would put that off as long as possible to ensure we maintained a healthy balance. That decision ended up being costly as we came to realize we should have spent more time on coding, as evident in our results above. This project helped us learn that a budget adds a new facet to time management and weight of what each aspect of design carries. As a group we learned that a whole lot more can be accomplished if everyone in the group has their eye on the goal and is willing to put in the time to see it through.