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Breath- Joystick - Breath- Joyst


									                   "Breath-Joystick" - Graphical Manipulator
                         for Physically Disabled Users

                         Grigori Evreinov 1, Tatiana Evreinova 2
Evreinov Grigori, Evreinova Tatiana. "Breath-Joystick" – Graphical Manipulator for Physically Disabled Users. Computer
Helping People with Special Needs. ICCHP2000. - Proceedings of the 7th International Conference on Computer Helping
People with Special Needs. . july 17-21, 2000, Karlsruhe, Germany. - p.p. 193-200.
The paper are devoted to investigation of possible ways of designing of alternative manipulators.
Described prototype of breath-joystick was designed and tested. Though this device is used without any
precise motions of the body (of fingers or hands), it has the technical and ergonomic parameters close
to conventional ones.

1    Introduction

Now for physically disabled users who cannot use a conventional, hand-operated pointing devices or
voice recognition systems, several alternative ways to operate computer or external assistive devices
were developed. Alternative input devices, such as foot-mouse, foot- trackball, head mounted pointers,
chin mounted joysticks, eye tracking have all been developed for interaction with WIMP interfaces
(Windows, Icons, Menus and Pointers). A head operated joystick/mouse and use a keyboard emulator
may based on techniques that include the use of different slope/rotation detectors or markers’ detectors
- sensors that track targets placed on a user’s spectacles or forehead; analysis of laser light reflected
from a user’s head [2]. Another approaches use “residual opportunities” of the manipulation by mass’
center of operator, by the face expression, by eyes motions or tongue ones.

In particular, graphic manipulator PadGraph [3] is based on adjustments of the mass’ center of the
operator. It allows the user to create graphic objects without use of hand operations. EagleEyes [4]
allows a person to control the computer by moving eyes or head. The method is based on the
measurement of electro-oculographic potential (EOG), through electrodes placed on the head. With the
help of EagleEyes, people can run educational and entertainment software, spell out messages, and
navigate through the internet just by moving their eyes. However, EagleEyes system requires to set five
electrodes with wires (!) on the head (face) of the user. A similar system [5] employs EOG generated
by eye travel to move a cursor. The signals of side on which teeth-chattering driven, right or left is
extracted from a pair of ear-microphone signals assigned to the roles of two buttons of ordinary mouse.
It is easy to chatter twice for double click, and three times for drag. The Cyberlink(tm) system [1]
combines eye-movement, facial muscle, and brain wave bio-potentials detected at the user's forehead
by three plastic sensors in a headband which is connected to Cyberlink(tm) interface box. The interface
box contains a bio-amplifier, signal processor and connects to the PC computer’s serial port.

1 Computer Centre of Rostov State University, 44/5-13 Lenin St., 344038 Rostov-on-Don, Russia
2 SPECVUZAVTOMATIKA Design Bureau, Lab. for Designing of Information Image Systems, Rostov-on-Don, Russia
Finally, Tongue Touch Keypad and Tonguepoint [6] were designed for people having different
neuromuscular diseases (quadriplegia, cerebral palsy etc.). Although not naturally to use for pointing
the tongue constantly performing sophisticated motor control for swallow, mastication or vocalization.
All of these alternative input devices are somewhat successful, but limited in many aspects, especially
by ergonomics and hygiene. In contrast to conventional input devices they are rigidly attached to the
head or another body part and in the better case implement a remote wireless control through radio or
infra-red communication system.

2   The Designing
Manipulator of joystick’s type was implemented as device having a high sensitivity to human
respiration flow. A circuit diagram of the breath-joystick is shown in Figure 1.

Six thermo-transducers are located in front of user’s mouth on a surface having special elements of
construction, which are dividing and selecting necessary components of directed air stream. Thus, a
prototype implements a function of two-dimension thermo-converter of coordinates, while two others
thermo-transducers must emulated a function of buttons. Thermo-transducers have a temperature little
bit above than environmental one (about 40?C), it allows to remove undesirable influence of a water
vapor, being in air flow.

                                Figure 1 Circuit diagram of the breath-joystick
          Figure 2 Part of circuit diagram of the breath-joystick using mouse’s microcontroller (e.g., HT6513B)

However, an evaluation      showed that this construction has a number of peculiarities, which can make
difficult a conventional    manipulation. In particular, if user selected menu item and he must “press
button”, during this time   a position of cursor may begin to drift in any direction. A similar limitation is
observed in a case of       dragging of objects. I.e. this construction required a special interface for its

Therefore we decided to make this device operate like a joystick rather than a mouse, but which would
use a mouse’s microcontroller and serial port. For a breath-joystick, the cursor must move when air
flow reach some threshold velocity (or of pressure) and must stop when air stream falls. To achieve this
operation only the electric circuit was modified (Figure 2).

In this case the device operates in the same way as most joysticks, in that there is a position (the
‘deadband’), which, when adopted (“threshold”), causes no movement. Whilst the air stream is outside
this deadband, the mouse cursor is moved with installed “Steps’ frequency”, and continues to move
until air flow will less than the threshold velocity. Thus, users wishing to move the cursor along X-axis,
will redistribute air flow with the help of their lips between respective thermo-transducers and must
keep air pressure until the cursor has reached the desired location. But in contrast to the first variant
(Figure 1) they may interrupt a manipulation in any point.
3   Results

During this pilot project there were evaluated different types of air flow’s transducers: piezoelectric,
tensiometric, thermometric and mechanic. Thermo-transducers have the best results regarding to
sensitivity, interference immunity, and technologic implementation.
The breath-joystick has been evaluated with a small number of users and with limited set of programs.
For a comparison of different prototypes we used such p         arameter as a performance's time of a simple
moving task: it was necessary to find the absent fragments of two objects and return these parts, i.e. to
displace and connect their with appropriate objects. The time of performance was shown on digital
watches in the bottom part of the game field (Figure 3).

However it is important to note, in contrast to the discrete “analog method” of the air flow’s processing
allows permanently to check the parameters of breath function of user and provides feedback about h     is
actions. Such opportunity will seem useful too at a designing of the therapeutic programs of respiration
training, particularly for the children having a weak breath function.

                                    Figure 3 Snapshot of the test-program
4    Conclusions

The described device can be used as an alternative input device for persons with minimal reliably
controlled physical movements (e.g., children who are multi-disabled and non-verbal from birth,
reanimation patients). The breath-joystick’s construction has the technical and ergonomic parameters
close to conventional ones. The results also suggest that there is potential for further development. For
example, the device can be also used for respiration training of children having a weak breath function.

5    References
[1] CHRISTEN, M., JUNKER, A., Cyberlink mindmouse: applications of brain wave computer control, in Proc. CSUN 99,
    Papers, Electronic Publications:

[2] EVANS, D.G., PETTITT, S. and BLENKHORN, P., A head operated ‘joystick’, in Interdisciplinary Aspects on
    Computers Helping People with Special Needs (eds.: Klaus, J., Auff, E., Kremser, W., Zagler, W.L.), ICCHP'96, Linz,
    Verlag R. Oldenburg, Wien Munchen, 1996.

[3] EVREINOV, G., AGRANOVSKI, A., YASHKIN, A., EVREINOVA, T., PadGraph, in: Human-Computer Interaction:
    Communication, Cooperation, and Application Design, Volume 2 of the Proceedings of HCI International '99 (the 8th
    International Conference on Human-Computer Interaction), Munich, Germany, (eds.: Hans-J.o.rg Bullinger and
    J.u.rgen Ziegler), Lawrence Erlbaum Associates, Publishers Mahwah, New Jersey, London, 1999.

[4] GIPS, J., DiMATTIA, Ph., CURRAN, F.X. and OLIVIERI, P., Using Eagle Eyes - An Electrodes Based Device For
    Controlling The Computer with your Eyes - to Help People with Special Needs, in Interdisciplinary Aspects on
    Computers Helping People with Special Needs (eds.: Klaus, J., Auff, E., Kremser, W., Zagler, W.L.), ICCHP'96, Linz,
    Verlag R. Oldenburg, Wien Munchen, 1996.

[5] HASHIMOTO, M., YONESAWA, Y., ITOH, K., New mouse-function using teeth-chattering and potential around eyes
    for the physically challenged, in Interdisciplinary Aspects on Computers Helping People with Special Needs (eds.:
    Klaus, J., Auff, E., Kremser, W., Zagler, W.L.), ICCHP'96, Linz, Verlag R. Oldenburg, Wien Munchen, 1996.

[6] SALEM, C., ZHAI, S., An Isometric Tongue Pointing Device”, in Proc. CHI 97 Electronic Publications:

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