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Poster Paper Proc. of Int. Conf. on Advances in Computer Engineering 2011

Wireless Tongue- Teeth Operated System for Physically Challenged People to Operate Computer M. Karthick Kannan, S. Pavithra Deepa, S. Kannimuthu Sri Krishna College of Engineering and Technology/ Department of IT, Coimbatore, India Abstract—In today’s world people with severe disabilities including those with spinal cord injuries, strokes find it very difficult to lead a self-supportive independent life without the help of others. Assistive technologies were introduced that would help them communicate their intentions and effectively control their environment. This helps them operate a computer and control the activities. This paper provides a technique based on tongue-teeth driven systems to support such people.

A. Working Principle In Tongue Drive System the tongue controller uses a special magnet attached to the user’s tongue with tissue adhesive. The motion of the tongue is traced by an array of magnetic sensors installed on a headset which is an external control unit worn outside. The magnetic sensors are mounted on a dental retainer and attached on the outside of the teeth to measure the magnetic field from different angles and provide continuous real-time analog outputs. These sensors measure the magnetic field generated by a small permanent magnet pierced on the tongue, which is the tongue controller.

I. INTRODUCTION A large group of assistive technology devices are available to support people with disabilities. It includes blow-n-suck (sipn-puff) device, chin control system, and electromyography (EMG) switch which are all switch based systems that provide the user with limited degrees of freedom. Apart from these we have devices based on electro-oculography, tilt sensors and the like. All these devices require some or the other interaction using a switch. Whereas a tongue-tooth driven system does not require any switch activity, rather it uses the concept of just sensing. This paper is about developing a wireless, noncontact, unobtrusive, tongue-teeth operated assistive technology called the Tongue-Teeth Drive System (TTDS). People with disabilities are trained to easily remember and correctly issue tongue commands to play computer games and drive a powered wheelchair around an obstacle course with very little prior training. We also try to issue other type of commands that can be transmitted to a computer to perform specified tasks.

Figure 1: Grain sized magnet along with the headset containing a receiver

The signals coming from the sensors are wirelessly sent to a portable computer for further processing. The signals received by the external controller unit are demodulated and demultiplexed to extract the individual sensor outputs. By processing the output signals, the motion of the permanent magnet and consequently the tongue within the oral cavity is determined. Assigning a certain control function to each particular tongue movement is done using software with MATLAB support. These customized control functions may then be used to operate a variety of devices and equipments including computers, phones, and powered wheelchairs. Before using the Tongue Drive system, the subjects trained the computer to understand how they would like to move their tongues to indicate different commands. A unique set of specific tongue movements was tailored for each individual based on the user’s abilities, oral anatomy and personal preferences.

II. TONGUE-DRIVE SYSTEM Individuals using a tongue-based system require only the movement of their tongue, which is especially important if a person has paralyzed limbs. A tiny magnet, only a size of a grain of rice, is attached to an individual’s tongue using implantation, piercing or adhesive. This technology allows a disabled person to use tongue for moving a computer mouse or a powered wheelchair. The tongue is used to control the system because unlike the feet and the hands, which are connected by brain through spinal cord, the tongue and the brain has a direct connection through cranial nerve. In case when a person has a severe spinal cord injure or other damage, the tongue will remain mobile to activate the system. Tongues movements are also fast, accurate and do not require much thinking, concentration or effort. The Tongue Drive system is also non-invasive and does not require brain surgery like some of the brain-computer interface technologies. © 2011 ACEEE DOI: 02.ACE.2011.02. 181

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Poster Paper Proc. of Int. Conf. on Advances in Computer Engineering 2011

Figure 2: Tongue Drive System Components

Figure 3: Layout of the proposed approach

Training requires commands to be repeated several times for computer recognition, but is relatively fast. Each command is defined by collecting changes in the magnetic field in relation to the tongue position. This data being stored in the database is used for later purpose of performing the required action. We also try to establish two modes of operation namely the stand-by and working mode so that the entire system may be temporarily switched off during activities like eating, sleeping.

III. PROPOSED APPROACH-TONGUE-TEETH DRIVE SYSTEM In the existing system we use a small piece of magnet attached to the tongue (tracer) and analyze its movements using a receiver that is placed in the headset. The signals being generated are recognized by the sensors in the headset. The recognized signals are then matched with the trained pattern to perform the corresponding operation. In the proposed approach we try to use touch sensors. The tongue controller uses a special magnet attached to the user’s tongue with tissue adhesive. The motion of the tongue is traced by an array of touch sensors. The touch sensors are placed on the individual’s teeth. As many sensors that would replace a normal mobile keypad may be used for this purpose. Certain magnetic effect is caused due to the small grain sized magnet that is pierced in the tongue of the individual. This magnetic field results in the generation of certain signals. As the individual moves his/her tongue the touch sensors recognize these signals. These signals are amplified and are sensed by the receiver in the headset. After sensing the signal we try to match it with the trained pattern. The degree of accuracy depends on training. The sensor output signals are wirelessly transmitted to an ultraportable computer and are processed to extract the user’s commands. The user can then use these commands to access a desktop computer, control a power wheelchair, or interact with his or her environment. During the training session the user must train the system to link each designated tongue movement to an action. We store the required actions to be performed in the form of commands for each signal being sensed.

A. Steps involved: 1)

Preliminary session:

Step 1: Implant the grain sized magnet on tongue. Step 2: Place the touch sensors on the individual’s teeth along with the required control unit and magnets.

Figure 4: Placement of sensor inside teeth

2) Training session: Step 3: Activate the touch sensor using tongue. Step 4: Sense the required signal using the external control

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Poster Paper Proc. of Int. Conf. on Advances in Computer Engineering 2011 unit attached with the headset. Step 5: Store the control function for the signal being sensed using some software.

CONCLUSION The TTDS provides people with minimal or no movement ability in their upper limbs with an efficacious tool for computer access and environmental control. This type of systems may be very helpful for persons with disabilities as a result of various causes, from traumatic brain injury and spinal cord injury (SCI) to stroke, who generally find performing everyday tasks extremely difficult without continuous help.

3) Active session: Step 6: Activate the touch sensor Step 7: Sense the signal being generated Step 8: Transmit it to the system and test for a match with the trained pattern Step 9: Determine the corresponding control function or the commands Step 10: Execution of the commands.

REFERENCES

B. Advantages The cranial nerve from the tongue is resistive to spinal cord injuries and hence can be used for people with different kind of disabilities for whom other traditional methods may not be supported. The tongue muscle is similar to the heart muscle in that it does not fatigue easily. Thus it is a suitable organ for manipulating assistive devices that can move faster and accurately. An oral device involving the tongue is mostly hidden from sight, thus it offers a degree of privacy for the user. This is not possible with those methods involving the movement of head or eye. The Tongue Teeth Drive users simply wear headphones that are commonly worn to listen to music, so the system is more acceptable to potential users. This hides the sign of disability which is not the case with other methods like the usage of sip-n-puff devices. The tongue muscle is not affected by repetitive motion disorders. The tongue is not influenced by the position of the rest of the body, which may be adjusted for maximum user comfort. The principal advantage of the TTDS is that a few magnetic touch sensors and a small magnetic tracer can potentially capture a large number of tongue movements, each of which can represent a particular user command.

[1] Xueliang Huo, Jia Wang, Maysam Ghovanloo. Introduction and preliminary evaluation of the Tongue Drive System: Wireless tongue-operated assistive technology for people with little or no upper-limb function. Journal of Rehabilitation Research and Development [2] Georgia Institute of Technology (2008, June 30). Tongue Drive System Lets Persons With Disabilities Operate Powered Wheelchairs, Computers. ScienceDaily. Retrieved June 4, 2011, f ro m , h t t p: / / w w w. s c i en c ed a i ly. co m / re l ea s e s/ 2 0 0 8 / 0 6 / 080630090821.htm [3] Huo X, Wang J, Ghovanloo M. Wireless control of powered wheelchairs with tongue motion using tongue drive assistive technology. Conf Proc IEEE Eng Med Biol Soc. 2008:4199-202. [4] Susumu Harada, Jacob O. Wobbrock, Jonathan Malkin, Jeff A. Bilmes, James A. Landay: Longitudinal Study of People Learning to Use Continuous Voice-Based Cursor Control [5] Bilmes JA Malkin J, Li X, Harada S, Kilanski K, Kirchhoff K, Wright R, Subramanya A, Landay JA, Dowden P, Chizeck H. The vocal joystick. : Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing; 2006; Toulouse, France. New York (NY): IEEE. p. 625–28 [6] Rafael Barea , Luciano Boquete, Jose Manuel Rodriguez-Ascariz, Sergio Ortega and Elena Lopez: Sensory System for Implementing a Human—Computer Interface Based on Electrooculography.

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