Wheelchair operates by power of thought

The wheelchair, developed at the University of Zaragoza, has a laser sensor and a screen that displays a real-time, three-dimensional virtual reconstruction of the wheelchair's surroundings. To steer the chair, a user concentrates on the part of the display where he or she wants to go, and electrodes in a skullcap detect the user's brain activity and work out the destination, the researchers said.

Sensors on the wheels keep track of the chair's position as it moves. The laser scanner detects obstacles to avoid collisions, so the chair can be used in unfamiliar surroundings, the researchers said in a paper.

Volunteers took just 45 minutes to learn how to use a prototype chair safely and accurately, said associate professor Javier Minguez, an expert in mobile robotic navigation and brain-computer interfaces who headed the chair-development team.

The prototype can handle only two thought commands a minute and can be used for only about two hours since the wet gel used to fix the electrodes to a user's head dries and loses its effectiveness.

An improved version that could go into commercial production is being developed, Minguez said.

The wheelchair is not the first to be controlled by brain waves, but is the first to incorporate mind-control in a system of real-time navigation, route planning and collision avoidance, computer science lecturer Palaniappan Ramaswamy of Britain's University of Essex, told New Scientist magazine.

Copyright 2009 by United Press International.