Design and Implementation of an Ultra-Low-Cost Smart Safety Stick with Multi-Level Obstacle Detection and GPS-Based Emergency Communication for Visually Impaired People in Developing Countries

Visual impairment significantly affects the mobility of visually impaired people and these problems are even higher in developing countries like Bangladesh as they are usually accompanied by undeveloped infrastructure, open drainage systems, risk of uncertain road incidents, etc. Conventional white cane neither provides enough physical feed-back to the user nor it supports emergency communication at remote locations. This study presents an affordable, IoT-enabled Smart Safety Stick designed to support visually impaired people in low-resource settings. The prototype has a listed material cost of BDT 2,323 (approximately USD 18.79). We designed the stick with an ESP32 microcontroller and three ultrasonic sensors for detection of obstacles at different height levels and pothole along the walking path and one resistive water sensor for flood conditions of walking path. It also equips a consolidated GPS and GSM module (NEO-6M and SIM900A) to provide real-time location to track down the disabled and transmit alerts at emergency SMS for predefined mobile contacts. When danger identified the stick instantly produces localized sound from the active buzzer to alert the user and an emergency switch is there which will send its exact coordinates to previously assigned mobile contacts via SMS when pressed. Utilizing a local power distribution network (18650 Li-Ion Battery and AMS1117 Regulator) it has become affordable, highly scalable and easily deployable substitute of high-cost advanced assistive devices. Experimental analysis has shown trustworthy data on detection of obstacle at various angles with promising latency range for transmitting emergency message.