Mouth-Controlled Text Input Device With Sliding Fuzzy Algorithm for Individuals With Severe Disabilities

Abstract

This study presents a novel mouth-controlled text input (McTin) device that enables users with severe disabilities to access the keyboard and mouse facilities of a standard personal computer via the input of suitable Morse codes processed by sliding window averaging and a fuzzy recognition algorithm. The device offers users the choice of four different modes of operation, namely keyboard-, mouse-, practice-, and remote-control mode. In the keyboard-mode, the user employs a simple mouth-controlled switch to input Morse codes, which the McTin device then translates into the corresponding keyboard character, symbol, or function. In the mouse-mode, the user is able to control the direction of the mouse movement and access the various mouse functions by inputting a maximum of four Morse code elements. The remote-control-mode gives the user the ability to control some of the functions of household appliances such as TV, air conditioner, fan, and lamp. Finally, the practice-mode employs a training environment within which the user may be trained to input Morse codes accurately and quickly via the mouth-controlled switch. Although this study presents the use of a mouth-controlled switch for the input of Morse codes, the form of the input device can be modified to suit the particular requirements of users with different degrees of physical disability. The proposed device has been tested successfully by two users with severe spinal cord injuries to generate text-based articles, send e-mails, draw pictures, and browse the Internet.

The fuzzy schmitt trigger algorithm regulates physiological action signals for disabilities auxiliary input devices

“…We used five 20 to 32-year-old males (subjects 1-5) as experimenters. Three students (subjects 1-3) had normal lifestyles and the others (subjects 4 and 5 [5]) were disabled persons who have severe spinal cord injuries. Subjects 4 and 5 both had C4-level injuries and were quadriplegic patients having no efficient voluntary movement, except for the eyes and mouth.…”

“…vth = vth-1 + ak e (5) Repeat steps 1-3, and the system adjusts the user status to allocate a specific point in order to increase the accuracy of signal translations. Adjust the low level and the fuzzy rules of the low-level FST are shown in Table 2.…”

“…The bio-signal input device combines with the Morse code Text input system [4,5], and allows users to control the computer or general appliances through bio-signal. Figure 6 illustrates a practical example where McTin is operated by a beginner where the user's head had three electrodes.…”

“…This study will use a single channel measurement to record the bio-signal of a specific action from the primary motor cortex [7], and will convert the bio-signal to a Transistor-Transistor Logic (TTL) signal as a Morse code signal by a Fuzzy Schmitt trigger algorithm, and then combine them with the Morse code Text input system (McTin) [5]. Hence, physical disabled patients can use this to communication with others.…”

Fuzzy Tracking and Control Algorithm for an SSVEP-Based BCI System

“…The input range of fuzzifier and the output range of defuzzifier were from −R f to R f and −R d to R d , respectively. Considering the performance and stability of a recognition algorithm in a microprocessor, the number of fuzzy sets was five [21]. The linguistic parameters of these five fuzzy sets were negative large (LN), negative small (SN), zero (ZE), positive small (SP), and positive large (LP).…”