Design of an Ultrasonic Distance Measurement and Obstacle Avoidance System for Visually Impaired Persons in Ibadan

This project designs an ultrasonic-based distance measurement and obstacle avoidance assistive device for visually impaired persons in Ibadan, Oyo State, South West Nigeria. Visual impairment significantly restricts independent mobility, and traditional white canes offer limited detection capability for obstacles above ground level such as overhanging branches, open cabinet doors, and vehicle side mirrors that are common hazards in Nigerian urban environments. The device consists of three HC-SR04 ultrasonic sensors mounted on a lightweight chest harness to provide frontal, upper-left, and upper-right field detection coverage. An Arduino Nano microcontroller processes the sensor distance readings and controls vibration motors embedded in the harness straps to provide directional tactile feedback proportional to the detected obstacle proximity. Audible alerts through an earphone provide supplementary warning for obstacles within 50cm. The harness is designed for lightweight wearability and incorporates a rechargeable lithium-ion battery with an estimated eight-hour operational lifespan. User acceptance testing was conducted with ten visually impaired volunteers at the Ibadan School for the Blind, where participants navigated a standardised indoor obstacle course with and without the device. Results show a 67 percent reduction in obstacle contact incidents when using the device compared to the white cane alone. All participants rated the directional vibration feedback as intuitive after a brief orientation session. Recommended improvements include integration of GPS and GSM modules for outdoor navigation assistance and caregiver location tracking. Keywords: ultrasonic sensor, assistive device, visually impaired, obstacle avoidance, Ibadan.