The system interprets commands
movements to operate maneuver
an electrically powered wheelchair;
© Georgia Tech
The Tongue Drive System is getting less conspicuous and more capable. Tongue Drive is a wireless device that enables people with high-level spinal cord injuries to operate a computer and manoeuvre an electrically powered wheelchair simply by moving their tongues.
The newest prototype of the system allows users to wear an inconspicuous dental retainer embedded with sensors to control the system. The sensors track the location of a tiny magnet attached to the tongues of users. In earlier versions of the Tongue Drive System, the sensors that track the movement of the magnet on the tongue were mounted on a headset worn by the user.
"By moving the sensors inside the mouth, we have created a Tongue Drive System with increased mechanical stability and comfort that is nearly unnoticeable," said Maysam Ghovanloo of the Georgia Institute of Technology.
The new dental appliance contains magnetic field sensors mounted on its four corners that detect movement of a tiny magnet attached to the tongue. It also includes a rechargeable lithium-ion battery and an induction coil to charge the battery. The circuitry fits in the space available on the retainer, which sits against the roof of the mouth and is covered with an insulating, water-resistant material and vacuum-molded inside standard dental acrylic.
"One of the problems we encountered with the earlier headset was that it could shift on a user's head and the system would need to be recalibrated," explained Ghovanloo. "Because the dental appliance is worn inside the mouth and molded from dental impressions to fit tightly around an individual's teeth with clasps, it is protected from these types of disturbances."
When in use, the output signals from the sensors are wirelessly transmitted to an iPod or iPhone. Software installed on the iPod interprets the user's tongue commands by determining the relative position of the magnet with respect to the array of sensors in real-time. This information is used to control the movements of a cursor on the computer screen or to substitute for the joystick function in a powered wheelchair.
REHACARE.de; Source: Georgia Institute of Technology Research