System could help blind people determine distance of objects

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Reading University scientists are continuing efforts to develop a system that could help blind people determine the distance or temperature of nearby objects.

The system currently relies on an external, body-worn sensor, which sends a signal in the form of an electric current through a wire coil attached to a vibrating electromagnet placed underneath a fingertip.

Speaking to The Engineer at the launch of a consultation on neurotechnological interventions in the brain, Prof Kevin Warwick said: ‘Ultrasonic sensors and the output from those sensors affect the current in the coil, which vibrates the magnet.’

The magnet will vibrate more when the sensor sends a relatively strong electric signal, which could indicate the presence of something hot or when a person was approaching an obstacle.

Warwick, a professor of cybernetics at Reading University and leader of the project, said three of his students have installed the electromagnets under their fingertips, adding that they are not particularly invasive compared to cosmetic piercings.

Ian Harrison, a PhD student at Reading University has magnets embedded in the middle and index fingers of his left hand.

‘The magnets are 3mm in diameter and 0.7mm thick. They are made of neodymium and coated in a biologically hard substance,’ said Harrison.

One issue with placing the magnets beneath the skin is that their strength is weakened. ‘The surface magnetism is 200mT, though when in the skin [it] is massively reduced,’ he added.

Harrison said the vibration of the magnets depends on the frequency of the input. ‘The standard 50Hz feels like a buzz,’ he explained.

The team, which began work on the system in 2008, currently has experimental results and is in the process of developing a project that will deliver more quantifiable data.