Accelerometer based football trainer

Abstract

The principal aim of this project is the design and construction of a football trainer. A football trainer is a system that is able to determ inate the strength of the impact of a football into a target. This system can be used to train and practice the kick of football players or as a game. To do that, the idea is to use an acceleration sens or, also called accelerometer. This device outputs an electrical signal that is proportional t o the acceleration applied on it. That means that it can detect any movement that has changes in its velocity. This definition includes any kind of vibrations, which is what an impact produce s in the target. By knowing the “quantity” of vibration it would be possible to know the strength of that impact. To build the system I will use an accelerometer fro m Analog Devices. This manufacturer provides an Evaluation Board to test the accelerome ter and learn how does it works. In the Evaluation Board the accelerometer interfaces to a low cost microcontroller which captures and converts the data from the sensor. Then the dat a is sent to the computer via serial communication. The idea is to use the design of the Evaluation Boa rd as a reference to build the acceleration sensor. Some changes will be made to adapt it to th e objective application, the football trainer. The most important change is to add a large memory capacity, so the information of the accelerometer could be stored on it and sent back t o the computer in a different moment. So it would be possible to record the data and store it i n the same board. That makes necessary to use and program a microcont roller to communicate with the external memory chip. So a microcontroller with a large numb er of input/output pins is needed, as the address and data ports have to be implemented. It w ill also need to communicate via RS232 with a computer, so a communication interface is re quired. Because all this characteristics it is very importa nt to make a good choose of this devices (the microcontroller and the external memory chip) to en sure the usability of the final system. I will use a +/-2g measurement range accelerometer (1g is the gravity on Earth surface, and equals 9.8m/s 2 ). One of the questions to answer is if this range will be enough to sense the impact of a full-strength football kick, as it is p ossible that it produces a movement with an acceleration of more than 2g. This will be determin ed by analysing the results. Finally, to complete the system, a computer softwar e will be needed. This software will have to send instructions to the microcontroller, allowi ng the user to choose the action he wants to take. Then it will have to receive the data from th e board and display it.