SeSaMoNet: an RFID-based economically viable navigation system for the visually impaired

Abstract

In this article, the authors present secure and safe mobility network (SeSaMoNet), a navigation and environment description system for users with visual impairments. The system is designed with attention to usability and accessibility features and for its great scalability. The spread of mobile technology such as handheld devices and related software, personal digital assistants and smartphones, wireless communication, text-to-speech, databases and finally radio frequency identification made it possible for the authors to build a portable, easy to use orientation and navigation aid that still has a great development margin. A double version, Symbian and Windows Mobile, allows quite every type of user equipment to be supported. The system aims to provide a non-intrusive and accessible way to expand the experiences of people with visual impairments and provide them with useful information about the environment beyond the tactile probing of the closest surroundings. This article expands previous work, detailing the usability and accessibility issues the authors faced and the new features introduced in the last period.

Keywords:

• navigation system
• visual impairment
• environment description
• RFID
• mobile

Notes

^1. Further explanation in Section 4.

^2. Patent Application n. 2734LU, filed on 26/10/2004.

^3. The cost is the result of the recovery, cleaning and transportation of about 5000 tags used in the setup of the track on the lakeside of Laveno.

^4. This value considers the inaccuracy related to the read range of the RFID cane and the error due to the delay of the played sound from the read event and the speed of the cane during the sweep with which the user explores the ground.

^5. Preliminary tests held at Sapienza University of Rome indicated that the needed coverage in indoor complex environments may be up to one device every 10 m². This is a very high density, but not if considering that ZigBee technology's first application field is domotics: likely scenarios may use even higher densities of devices in indoor environments.