A WiFi tracking device printed directly on textile for wearable electronics applications

Despite the abundance of localization applications, the tracking devices have never been truly realized in E-textiles. Unobtrusive and flexible integration of tracking devices with clothes is difficult to achieve with standard PCB-based devices. An attractive option would be direct printing of circuit layout on the textile itself, negating the use of hard PCB materials. However, due to high surface roughness and porosity of textiles, efficient and reliable printing of electronics on textile has remained elusive. In this paper, an interface layer is first printed on the textile to facilitate the printing of a complete localization circuit and antenna for the first time. The tracking device utilizes WiFi to determine the wearer's position and can display this information on any internet-enabled device, such as smart phone. The device is small enough (55 mm × 45 mm) and lightweight (22g with 500 mAh battery) for people to comfortably wear it and can be easily concealed in case discretion is required. The device operates at 2.4GHz with communication range of up to 55 meters, and localization accuracy of up to 8 meters.