Smart optical wireless sensor for real time swimmers feedback

Water is difficult environment for a wireless communications during swimming. A novel swimmer feedback system to enable consistent swimming pace consists of a ring of eight green LEDs which transmits information from a wrist mounted accelerometer using frequency shift keying (FSK) and on-off keying (OOK). The receiver on the goggles used an integrated detector preamplifier (IDP). The percentage of received optical data was determined for different positions for the swimmer´s hand in different swimming styles (Freestyle, breaststroke, backstroke and butterfly). The system was evaluated in air and water to evaluate the preferred arm position and LED for communications. The stroke rate was determined using a 3-axis accelerometer and the interpretative firmware is different for each swimming style. One or more LEDs will be switched on during the cycle to achieve a maximum link performance. This system can be employed in pacing swimmers in both pool and open water swimming.