Michigan State University ECE480 Pre-proposal Design Team 1 Fall 2008 Vinod Natla Kyle Coveart Jeli Joegiono Ryan EveraertExecutive Summary We will be building an accessible automated machine that will accurately cut material (our main focus is pleated ribbon) to a user specified length. The machine will have a simple interface for use by the impaired and will provide audio/visual feedback of system settings. The machine will be constructed using a collection of simple electric motors, custom built mechanical components, and integrated circuits. The final product will require minimal supervision from the user, will be properly safeguarded, and will be sufficiently mobile. The total cost of this project is expected to remain well within budget limitations. A far reaching goal of this project is to help create more employment opportunities for disabled persons. INTRODUCTION Problem to be Addressed One of our sponsors, Michigan business Lettuce Duit, has many manually operated machines in their factory that are used for general purpose cutting of materials. Currently, workers are cutting pleated ribbon material to length manually by hand using only scissors and rulers. Lettuce Duit would like to see an automated machine made that can efficiently handle this task. It is also required that the machine to be built be operable by individuals with disabilities (mainly seeing, hearing, and learning disabilities). Also, in terms of production volume, the machine should be able to at least match the production speed of the individuals who are currently doing the task by hand. Sponsor Specifications: - Machine will be manually fed material by the user initially, and the machine can then take over automatically with minimal aid from the user - Machine can accurately cut material to a length of zero to seventeen inches, with 1/10 inch resolution - Machine accessible to disabled persons - Machine has simple user interface, with audio/visual feedback for the impaired - Material to be cut will have width no greater than two inches - Machine will be electrically and mechanically safeguarded - Machine must be reasonably portableBACKGROUND Research Conducted for Design Solutions Given the nature of the ribbon cutting task, we needed to find components that could successfully replicate motion in a controlled manner. We began by researching electric motors, particularly stepper motors and servo motors. These types of motors were considered because of their smaller size and precision control capabilities, while still being powerful enough to handle the expected demands of our final product. Finding that stepper motors are commonly used inside of printers to control the inkjets, we decided to focus on them and their implementation. For the audio/visual feedback of the machine, we researched many varieties of devices. For the display, we needed to locate a device that could display simple numeric information and be easy to read for the impaired. A collection of 7-segment display modules was decided upon because we had no need for more complicated display technologies, such as the dot matrix. Only a small amount of research was conducted for the audio feedback components because one of our sponsors, Stephen Blosser, donated to us an audio chip. Stephen is familiar with the functionality of the chip and is confident it will fulfill the needs of the project. We will acquire the software necessary to program the chip and implement it after becoming adequately comfortable with its functionality. To bring together and control these various components, we found that the Microchip 18F4520 microcontroller, provided to us by the ECE480 course curriculum, would be more than adequate due to the relatively low amount of processing power and task handling required by the project. Regarding the mechanical components of our design, we researched many premade and custom built options for linear motion stages, clamps and actuators. Some linear motion devices were even found to have stepper motors already built into them. Though many of the devices we came across would functionally fill the needs of the design, product cost and turn-around time prevented these options from being feasible for the scope of this project. However, our sponsor Stephen Blosser offered to build and machine these components himself free of charge. This solution was the best fit to our project because we can work closely with Stephen in a timely manner to obtain exactly the functionality we require.Previous Pertinent Work In 2004, an MSU design team created a talking dryer for the company Whirlpool. This dryer provided voiced audio feedback, allowing the visually impaired to successfully change the machines settings and use the device to its fullest extent. We are taking a similar approach in making an automated machine operable by those with hearing and seeing disabilities. Also at MSU, a design team reconfigured the circuitry of a beep baseball system in spring of 2008. From a technical standpoint, their project provided audio feedback to visually impaired users as well. From a functional standpoint, their project allowed disabled persons to participate in previously inaccessible activities. Other examples of accessible manufacturing equipment, similar to our project, are becoming more abundant in major facilities, including that of Ford and General Motors. CONCEPTUAL DESIGN DESCRIPTIONS Early Design Considerations Upon meeting with our sponsor Stephen Blosser, we found that he already had an early design in mind. Due to the fact that Stephen had already generated a plausible design, our early design considerations were somewhat expedited. That said, the final design we are actively working toward underwent a few reforms before it reached its final state. Our initial design included two linear motion stages, four stepper motors, a rotary cutter, two screw-clamps, a simple user interface, and a central microcontroller. Of the four stepper motors, we intended to us one to both drive and position the movable clamp on its linear stage, one to drive the cutter on its linear stage across the material, and two to turn the screws of each screw-clamp. We also envisioned an automated feeder to the machine that could sense and intake material through a set of powered rollers. After a discussion concerning production speed of the
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