Enabling Independent Swimming for Blind and Visually Impaired Athletes
H.G. Stallenberg (TU Delft - Mechanical Engineering)
G. Smit – Graduation committee member (TU Delft - Mechanical Engineering)
F.C.T. van der Helm – Mentor (TU Delft - Mechanical Engineering)
R.M.A. van der Slikke – Mentor (TU Delft - Mechanical Engineering)
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Abstract
Blind and visually impaired (BVI) swimmers cannot independently detect the end of a swim lane, impacting their safety and training efficiency. As a result, BVI swimmers rely on a ‘tapper’, which limits their ability to train independently and increases the risk of injuries. This thesis investigates whether transmitter-based technology can enable BVI swimmers to independently detect their turning point in a swimming pool.
Design requirements were used to evaluate three transmitter-based technologies: radio frequency identification (RFID), ultrasound, and Ultra-wideband (UWB). Based on range, accuracy, and power consumption, RFID was excluded. Subsequently, after performing preliminary experiments and comparing concept designs, UWB was selected for further development.
A test setup was designed with the Pozyx UWB kit, and its ranging performance was characterized on land using one and two anchors. After integration of the haptic motor and a waterproof enclosure, the test setup was validated in a swimming pool. These validation tests included static measurements at and above the water surface, as well as dynamic tests with a swimmer performing front crawl and breaststroke.
The results showed that the UWB system provided reliable ranging up to eight meters, with performance decreasing significantly beyond this distance. Furthermore, system accuracy degraded when the wearable was partially or fully submerged or when the haptic vibrations led to multipath propagation. During the dynamic tests, false negatives occurred more frequently than false positives, particularly under non-line-of-sight (NLOS) conditions, when the swimmer’s head obstructed the UWB signal.
These results demonstrate the potential of Ultra-wideband as a detection method within an eight-meter range, which is sufficient to trigger the feedback signal. However, for full lane coverage, additional anchors are required. This thesis presents a proof of concept, and further development is required to miniaturize the design, calibrate the ranging system for consistent performance across different swimming pools, and improve the feedback component.