Using Magneto-Inductive Sensors to Detect Tongue Position in a Wireless Assistive Technology for People with Severe Disabilities

We have developed a wireless assistive technology, called Tongue Drive, to enable people with sever disabilities control their environment using their tongue movements. A small permanent magnet is attached to the tongue as a tracer. The magnetic field variations due to the tongue movements are detected by an array of magneto-inductive sensors mounted inside the mouth on a dental retainer or outside on a headset, similar to a head-worn microphone. The sensor outputs are wirelessly transmitted to a PC/PDA, worn by the user on his/her body or wheelchair, to be processed. The PC/PDA classifies the signals and converts them into control commands, which are then communicated to target devices in the user's environment. We have built a prototype Tongue Drive system on a baseball helmet using off-shelf components. Preliminary results showed that our sensor signal processing algorithm can effectively minimize external magnetic interference, and translate different tongue movements into six individual mouse control commands for computer access.