Machine Control Design Project
See project file here.
A “cookie factory” needs my team to design a device that will put a chocolate drop on top of their peanut butter cookies. Using the knowledge given by PLTW’s Principles of Engineering course, I created a machine utilizing VEX equipment that is able to solve the cookie factory’s needs.
For this project, we are able to go down a few different routes in order to fulfill the design requirements and solve the problem statement. By using VEX parts, nearly all design possibilities utilize some sort of track mechanism to transport the ‘cookie’ and deliver the ‘chocolate chip’ on top. While wide tank track and thinner cables could be used, both relied on a sprocket system in order to power the mechanism. For the sensors, design possibilities varied between sonic sensors to sense when the ‘cookie’ was positioned correctly, to bump switches to determine if the ‘cookie’ was in the proper place manually. We opted to utilize a more simple time-based approach, in which we iterated through each cycle of the program using a for loop and time constraints within the code.
For programming, options varied based on what type of loop the design called for. Possibilities included while loops, if statements, and for loops (which is what we ultimately used) in order to iterate the program effectively and prevent arduous hard coding from taking up the bulk of the engineering design process. While if statements could’ve been used in our design along with sonic sensors, we found that due to the physical limitations of the sensor itself it could not be used reliably within our design to yield the same outcome we wanted. In the end, we opted for a for loop approach that enabled us to iterate as many times as we wanted, only having to press a bump switch in order to start the program (which was accomplished by using an if statement to check whether the button was depressed).
The most difficult part of the problem was definitely troubleshooting the code to get it to work. While if we had gone with a sensor-based design it might have been easier overall to program, by hard coding the time delays between each motor movement it made it more difficult for us to figure out the exact numbers.
One feature that could have been added would be a final area for the cookie w/ chocolate to lay once off the conveyor, instead of just falling off onto the base platform. Another would be a pusher mechanism that is timed alongside a motor in order to iterate each new cookie being pushed onto the conveyor, not requiring human motion to put one on. This would require more effort, but the machine itself would be more self sufficient.
