Low-Cost Ultrasonic Range Improvements for an Assistive Device

Area of Science:

• Assistive Technology
• Biomedical Engineering
• Sensory Substitution

Background:

• Visually impaired individuals face significant challenges in mobility, primarily concerning obstacle detection and avoidance.
• Existing electronic mobility aids are often complex and expensive, limiting their widespread adoption.
• There is a need for affordable, user-friendly assistive devices to enhance the independence of blind people.

Purpose of the Study:

• To design and develop a low-cost, enhanced ultrasonic-based mobility aid for the visually impaired.
• To improve the accuracy and reliability of obstacle detection by minimizing interference from other ultrasonic sources.
• To create an accessible device that integrates with a user's mobile phone, reducing cost and complexity.

Main Methods:

• Modification of a standard HC-SRF04 ultrasonic range sensor with phase modulation to distinguish echo origins.
• Development of a system that utilizes phase modulation to filter out interfering signals, enhancing detection accuracy.
• Integration of the sensor with a mobile phone application, informed by user and trainer feedback, for ease of use and cost reduction.

Main Results:

• The modified ultrasonic sensor successfully discriminated between direct echoes and external interference, improving detection reliability.
• Field testing with twenty visually impaired individuals demonstrated a reduction in involuntary obstacle contacts.
• User satisfaction surveys indicated a high level of acceptance and perceived improvement in mobility and security.

Conclusions:

• The developed low-cost electronic aid effectively addresses the limitations of current mobility devices for the visually impaired.
• The phase modulation technique significantly enhances the accuracy and security of ultrasonic-based obstacle detection.
• The device offers a practical and affordable solution, reducing insecurity and improving the mobility of blind individuals.