Indoor Wayfinding Based on Wireless Sensor Networks for Individuals with Multiple Special Needs

Wayfinding systems are an assistive technology targeting disabled patients who are mobile and need to travel in both indoor and outdoor environments, thus increasing workplace and life independence. Such a personal guidance system can improve the quality of life and minimize risks such as wandering behavior, which has been previously observed in patients with acquired brain injury. The proposed system called AssistMote is a full-ledged navigation solution using wireless sensor networks (WSN) for ambient condition detection, routing engines for navigation, and PDAs as the user interface, to assist with indoor wayfinding for individuals with multiple special needs. Ambient intelligence such as inadequate illumination and wet floors can be critical to wayfinding for the targeted population. The routing algorithm is based on the innovative use of Dijkstra's shortest path with the special requirements of navigation applications taken into account. The study reports the prototype design, experiments, and detailed performance evaluation based on computer simulations and field trials of eight human subjects with multiple disabilities who participated in pedestrian navigation in a five-floor building with 91 sensor nodes. AssistMote achieved 95% success compared with 37.5% in a controlled study that used verbal instructions and paper maps.