**3. Smart braille-block-based route guidance technology for the visually impaired**

The visually impaired people have a lot of difficulties due to their visual limitations when moving outside. However, recently, various route guidance support systems using GPS signals have been developed and introduced to help them find their destination, but there are still many difficulties in mobility in underground and indoor areas such as railway stations where GPS signals cannot be used. Various technologies that can use location information in this indoor area are being developed, but most of them require the construction of many infrastructure facilities, and at the same time, users must have a dedicated terminal or additional device to use these services, etc. [6–9]. Therefore, it is difficult to put it into practical use. In this chapter, to increase practicality through the analysis of these existing studies, IoT-sensor-based route guidance technology was designed through positioning in the indoor space so that the user installs only the smartphone app and minimizes the construction of infrastructure facilities [7, 13].

## **3.1 Overview of IoT-sensor-based route guidance technology**

Braille blocks for the visually impaired are installed on the floor of most indoor areas, including railway stations, and rounded type is installed on the path of the braille blocks, and linear type is installed at junctions or end points to help the visually impaired. In this chapter, the IoT sensor is embedded in the braille block installed on the floor, and the mobile app determines the user's location and calculates the route to their destination based on the signal from the sensor. Following the confirmed user's current location and desired route, route information is guided through

voice and screen of the mobile terminal. **Figure 8** shows the outline of the route guidance technology in the indoor area proposed in this chapter and the application screen of the mobile terminal.

The app screen is used by the visually impaired, not the general public, must be designed in accordance with the national app accessibility standard, and must also be certified by an authorized agency. The app developed in this chapter is designed and certified according to this standard. When the user's location information in the indoor area is confirmed, a route guidance service to the desired place is possible, and additionally, information on major facilities around the moving route and risk information can be provided. In other words, until now, it was impossible to provide various pieces of information to improve mobility as GPS signals were not available in indoor areas. However, through the location information through the IoT sensor proposed in this chapter, it is possible to apply various services for the visually impaired to support movement in indoor spaces. **Figure 1** shows an overview of route guidance technology for the visually impaired.
