Material Sorter
Procedure
Lane, Kaleb, and I had the task to create a sorter capable of separating recycled materials (marbles) into separate bins. Our sorting machine had to be completely automated and tested with three of each of three different types of marbles. The machine had to be efficient enough to be able to run under two minutes.
Brainstorming
The first thing that the group brainstormed was which method we would like to use including sorting by weight, light penetration, size, texture, or reflection. We decided that the best method would most likely be to sense the reflection that each marble gave off. The next step was to pick which marbles would work the best for giving off different reflections and we ended up choosing the steel, the clear, and the wooden marbles. Our next design that we had to make a decision on was the shape of our hopper. Our choices were either a straight hopper or a funnel hopper, and we ended up choosing the funnel hopper because it would be more efficient.
Decision Matrix
During the brainstorm process, we had a hard time choosing between ideas that would work best for us. To help solve this problem, we used a decision matrix to see the pros and cons of each idea. This helped us choose between a funnel slide, a straight slide, and a rail with teeth and gears that could move marbles. The funnel slide won by one point. We also used this method to choose the type of sorter we would use. Two wipers beat one wiper by six points.
FInal design solution
We sketched out what we had in mind for our final machine including bins, hopper, base, wipers, sensor, and motors. More was added to the machine later on to make it more efficient.
design modifications
We started to realize that using two stoppers to stop the marbles wouldn't work because the first stopper would let out more than one marble at a time and the purpose is to only let one through. By replacing the first stopper with a wheel similar to a water wheel, we got it so that only one marble would only go through at a time.
After the wipers were built, we realized that they were too tall for the marbles, so we designed something which wasn't too tall and would direct the marbles to there proper location.
In order to fit on our base, we didn't make separate pathways for the marbles after the wipers, but instead used one flat piece of metal and used guiders to lead the marbles to their bins.
Along the way, we ended up adding a flashlight and moving the light sensor to get a better reading of the reflection.
After the wipers were built, we realized that they were too tall for the marbles, so we designed something which wasn't too tall and would direct the marbles to there proper location.
In order to fit on our base, we didn't make separate pathways for the marbles after the wipers, but instead used one flat piece of metal and used guiders to lead the marbles to their bins.
Along the way, we ended up adding a flashlight and moving the light sensor to get a better reading of the reflection.
Programming
Programming was by far the most difficult part for the group. None of us really felt completely comfortable with the programming portion of this project. Before we started, we made a list of operations in the order that would work for us starting at the first marble being let through all the way to the wipers moving to the right direction and the whole process being repeated. At first, we were able to get the wheel, the flashlight, and the stopper to function properly, but as we progressed farther into the program and started to try to get the wipers to work, our program no longer seemed to work. At one point, we couldn't even get the flashlight to turn on. We wanted to give up, but we figured out a few things around the end of our time period. We never completely got our wipers to turn where the marbles were supposed to go mostly because the marble's light reflection values would never stay the same. If we had a longer time period to figure out how to keep the values the same and work out some of the other problems we were having, I'm sure we could have made it work.
conclusion
What started out as a great idea slowly spun downhill as we got into the programming portion. We ended up changing mechanical components of our machine to make programming easier but in the long run it just messed us up. Also, we did a lot of experimenting with our program at the beginning and found solutions that worked, but tried to better these solutions without keeping any documentation of our solutions that worked. Because we did this, we lost all of our hard work and ended up with a mess. If we could do it all again, I would stick to the initial design because it would have worked. I would have also kept documentation of every experimental program that worked for us and added it up in the end to create a solution to our programming problems. At times, I just wanted to rip the entire machine apart and start over, and if we had more time I probably would have. This was a great learning experience of how you should always keep a record of everything you do. I also feel like I have a stronger understanding of programming after this project.