My master’s thesis is about a development of an embedded sensory circuit and an Android application associated to it, which is capable of measuring and indicating an additional parameter used in rowing sports.
The Waterstars Sportelektronika Kft. has developed an instrument in recent years, which can measure, process and display the most important parameters of rowing sports. These are namely the stroke rate, speed and heart rate. In this context, it emerged an idea about a realization of a new embedded instrument, which could be a new member of the Waterstars product family with measuring another important parameter, called Speed on Water. The idea to prepare a complete, functional product has become the main task of my master’s thesis. To measure the Speed on Water value, a two-pole magnet propeller should be put into the water, wherein the propeller rotation provides magnetic field changes, which gives the necessary information to determine the current speed. The embedded system what I have developed – called Impeller – has the ability to perceive the magnetic field strength changes caused by the propeller in induced voltages. After the analog signal filtering, amplification and digitization a microcontroller unit can calculate the current speed, which is then transmitted to the Waterstars main device or an Android smart device with radio communication. During development two different prototypes has been made, where the main differences occur in the kind of radio communication. The first version with an RFM73 module, while the second version with modern Bluetooth Low Energy, or ANT/ANT+ has the ability to establish a connection with the surrounding environment.
In parallel with the creation procedure of the embedded system I have made an Android-OS application, which can take advantage to realize the functions and behaviors of the Waterstars main device with using the sensors of smart phones and tablet devices, while it reaches a much more polished interactive graphical interface, and furthermore to be able to communicate with the Impeller circuit by using Bluetooth Low Energy, or ANT/ANT+, too.
My thesis first gives an insight into the world of rowing sports in touching with the biomechanical background, and after that it will present the main steps of the development of the embedded system and Android application to the reader, and of course the behaviors and appearances of the finished products.