MORE than 285m people across the globe suffer from visual impairment. Yet the tools to assist the blind in walking have changed little since the 1920s, when their canes started being painted white to make other pedestrians more aware of their presence. The gizmos that do exist have tended to be expensive and clunky, and have not caught on. This may change if Anirudh Sharma, a 24-year-old computer engineer from Hyderabad, a city in the Indian state of Andhra Pradesh, has his way.

His innovation, dubbed “Le Chal” ("take me along" in Hindi) pairs a smartphone app with a small actuator sewn inside the sole of one shoe via Bluetooth. The user tells the phone his desired destination, which is translated into electronic commands using voice-recognition software. The app, which can be programmed to run in the background, fetches the local map of the area. The phone’s Global Positioning System (GPS) tracks the person’s location in real-time, telling the actuator to vibrate when it is time to turn. The side of the shoe where the vibration is felt indicates which way to go. Mr Sharma opted for a vibrating signal because for the blind, who rely on their sense of hearing to make sense of the environment, audio feedback is a distraction.

The system does not require constant internet access. Once downloaded, maps can be stored locally and combined with GPS data. The app uses Open Street Maps (OSM), an open-source rival to Google Maps. OSM allows editing, a helpful feature in updating rapidly changing urban landscapes. A speed-dial function can rapidly retrieve the most frequently visited routes. 

The shoe pod is also equipped with an obstacle-detection mechanism. A sensor in the tip of the shoe, devised by Mr Sharma’s business partner, Krispian Lawrence,  scans the vicinity using sonar, which emits ultrasounds that bounce off obstacles, indicating their presence. The shoe sets off a distinct pattern of vibrations to alert the person of any obstruction and guides him around it.

For now, the footwear, being tested at the L.V. Prasad Eye Institute, one of India’s biggest eye-health facilities, may be most useful in areas with little or no traffic, such as quiet residential streets or parks. The challenge, Mr Lawrence says, is to get the algorithm to tell an uncovered manhole from a flight of stairs, but he expects it to be able to do so in due course. Dealing with moving obstacles like cars may take longer, though the pair are working on ways to alert wearers not just about cars' presence, but also their speed. 

To ensure that the final product resembles a regular shoe, fashion technologists are being consulted to help with ergonomics and design. Mr Sharma and Mr Lawrence, who started a company called Ducere Technologies to commercialise their idea, say their high-tech brogues should not cost more than an ordinary, stylish pair. Many of the world's visually impaired will like the sound of that.