By Reyhana Mahomed
David Orpen, an Honours student in the Department of Physics and Electronics, invented a ball speed measurer for a cannon used in cricket training and tennis players.Port Elizabeth businessman, Peter Howard, of Kanon Ball Machines, manufactures office, business and sporting equipment. This sporting equipment includes cricket bowling machines and tennis ball machines. Howard wanted to find out the speed the balls travelled at after leaving the cannon, thus, he approached the Department of Physics and Electronics. Orpen, after completing a course on Computer Interfacing, undertook the project. “I felt confident that I could come up with something to measure the speed the ball travels at,” said Orpen.While it took Orpen five minutes to think of something that would be able to measure the speed of the ball for the cannon, it took him a month to implement his ideas. However, he encountered two problems. Firstly, as the microprocessor that he added to his ball speed measurer is static, it often hung in the way of the tube Orpen invented, and caused the speed to be inaccurate. Secondly, the infrared beams are subject to interference from other infrared sources, such as the sun.“I solved both of these problems with the help and advice of Richard Grant [head of the Department of Physics and Electronics],” said Orpen. He explained how the tube that fits over the end of the cannon functions: “The device measures the velocity of something passing through the gun barrel. Two infrared beams are broken by the ball as it passes through and the calculator and timer measures the velocity.” Orpen used a microprocessor which starts and then quickly stops, thus counting the microseconds of the speed at which the ball travelled. He also developed a large seven segment display which shows the speed in km/h. Orpen’s design will be incorporated into a module that can be purchased by users of the cannon.