1. Senior Capstone Design Project – Electrical Engineering – 2016 In and Out Line Monitoring System for Volleyball Kelley White Advisor: Professor Buma DESIGN: The prototype is a 6 foot portion of the end line It is powered by a rechargeable 9V battery and has an LED indicator for when the ball lands on the line It is simple to install with just an overlaying tape over the existing line. Figure 1: Block Diagram of line monitoring system The force sensitive resistors (FSR) are the sensor input. They are 2 feet long and have a sensing area of ¼ inch wide A volleyball hits the surface with a minimum diameter of 1 ½ inches. Therefore with a 2 inch wide boundary line the sensors must be aligned as shown in figure 2 in order to have an accurate system. Figure 2: Alignment of force sensitive resistors Safety is a very important part of the line monitoring system and therefore the line must be thin to be negligible to players. Using only thin components for the line, the line will be 0.5 mm thick. Figure 3: Layers of line monitoring tape INTRODUCTION: Volleyball is a fast paced, competitive game and line calls are an issue that continuously come up in any level of play Lack of focus, speed of the ball and inaccuracy of the eye have caused many incorrectly judged calls in the game of volleyball An in and out line monitoring system will relieve the stress from line judges as well as ensure good calls and a fair game for coaches and players The line monitoring system consists of force sensitive resistors (FSR) built into a tape which lays over the boundary of the court A microcontroller receives a signal from a force and the algorithm decides if the force is a ball or a player The output is an LED light to indicate a ball has hit the line The line monitoring system will run on a 9V battery for 10 hours, which is long enough to monitor a one day volleyball tournament TESTING : There are two different ways I went about differentiating the signal of a ball and a person: by duration of the impact or the force of the impact. The force sensitive resistors do not measure high force, therefore the hope was that there was a large difference in the duration of the two contacts. Figure 4: Output signal of a run Figure 5: Output signal of a ball bounce The duration of the run is 0.258 seconds and the duration of the bounce is 0.026 seconds. Through these results and further testing, it is clear that the impact of a player takes much longer than the impact of the ball. ALGORITHM: Using the Arduino Uno as the microprocessor, the flow chart in figure 7 was used to code the system Figure 6: Set up of system Figure 7: Flow chart of algorithm RESULTS: Measurements of the Arduino and FSR’s produced an average percent error of 4.14%. Four scenarios were tested in the volleyball gym: two foot jump, run, hard hit and free ball. With ten tests each scenario, there was an error rate of 10% Run Hard Hit CONCLUSTIONS & FUTURE WORK: My in and out line monitoring system for volleyball successfully differentiate between a ball and a player Future work includes expanding the line monitoring system to the whole court and increasing the accuracy of the system by continued testing and modifications. ACKNOWLEDGEMENTS: Union College, SRG Funding, Gene Davison, Union College Volleyball, Coach DeRan, Coach Brown and Coach Katalina and all faculty and students who helped with the in and out line monitoring system.