Validation of an eBAT as a mobility aid for blind people

Low-Cost Ultrasonic Range Improvements for an Assistive Device

To achieve optimal mobility, visually impaired people have to deal with obstacle detection and avoidance challenges. Aside from the broadly adopted white cane, electronic aids have been developed. However, available electronic devices are not extensively used due to their complexity and price. As an effort to improve the existing ones, this work presents the design of a low-cost aid for blind people. A standard low-cost HC-SRF04 ultrasonic range is modified by adding phase modulation in the ultrasonic pulses, allowing it to detect the origin of emission, thus discriminating if the echo pulses come from the same device and avoiding false echoes due to interference from other sources. This improves accuracy and security in areas where different ultrasonic sensors are working simultaneously. The final device, based on users and trainers feedback for the design, works with the user’s own mobile phone, easing utilization and lowering manufacturing costs. The device was tested with a set of twenty blind persons carrying out a travel experiment and satisfaction survey. The main results showed a change in total involuntary contacts with unknown obstacles and high user satisfaction. Hence, we conclude that the device can fill a gap in the mobility aids and reduce feelings of insecurity amongst the blind.

An intelligent indoor guidance and navigation system for the visually impaired

Intelligent guidance in complex environments where various procedures are required for navigation is critical to achieving mobility for the visually impaired. This study presents a newly developed software prototype with a hybrid RFID/BLE infrastructure to provide intelligent navigation and guidance to the visually impaired in complex indoor environments. The system enables the users to input their purpose via a specially designed user interface, and provides intelligent guidance through a chain of destination targets which are determined according to the inherent procedures of the environment. Path optimization is performed by adaptation of the traveling salesman problem, and real-time instantaneous instructions are provided to guide the users through the predetermined destination points. For evaluation purposes, a hospital environment is constructed as an example of a complex environment and the system is tested by visually impaired participants. The results show that the intelligent purpose selection and destination evaluation mechanism modules of the system are found to be effective by all the participants.