Electromagnetic Technology for a New Class of Electronic Travel Aids Supporting the Autonomous Mobility of Visually Impaired People

It is well known that the most common and largely used assistive technology among the visually impaired community is the white cane. Despite it is a passive technology with a very limited range of work, its easiness of use and low cost make still prevalent its use. Many technologies have been proposed as alternative assistive devices (in literature and on the market) to improve the autonomous mobility of people affected by eye diseases. Nevertheless, whatever is the physical quantity used by these active assistive technologies - mainly ultrasonic or optical sensors - they present many limitations and none of them adequately meets the international guidelines defined for the electronic travel aids and the specific requests coming from the visually impaired community. This chapter aims to provide an overview of the existing travel aids for people affected by visual disorders, discussing pros and cons of available technologies, and to describe the design and the characterization of a novel class of electronic travel aids based on electromagnetic fields, whose advantages, with respect to the traditional ultrasonic and optic devices, will be explained. Starting from a laboratory prototype, the aspects relative to the miniaturization of the device will be discussed, with a particular attention to the realization of a small radiating element to be attached onto the cane. Operative tests with a blind end user will be reported, demonstrating several potentialities of the electromagnetic technology: detecting in advance (few meters from the user) dangerous objects of different shape and material, detecting the presence of obstacles located at chest or head levels, providing the position of the obstacle respect to the user, easiness of use, etc.