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Apprentissage de la lecture tactile du Code SIXTEM par boucle de rétroaction pilotée par microordinateur Apple II

Experiment Findings · June 1986 CITTIONS READS

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2 authors, including:

Jean-Pierre Bachy

University Joseph Fourier - Grenoble 1

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Tactile learning of code SIXTEM View project Project of simplified keyboards for code SIXTEM View project

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Jean Cucciniello

IEG 3rd year Engineering Physics LIME UJF Grenoble March-June 1986

Person in charge of the internship: Mr. Quezel , director of LIME


TOUCH READING KEYBOARD FOR THE VISUALLY IMPAIRED




This project, by the design and the realization of a tactile keyboard constitutes a study of the feasibility of a method of reading intended for the visually impaired.




I - Role of the reading keyboard


1 - General information on writing:

In general, writing involves the following mechanisms:


This control operation is normally done visually and usually in a sequential mode (we do not check each letter after having written it but rather a word, a line or even a sentence, more or less long sequence of characters). For blind people who write in Braille, feedback is by touch; (they write with a punch the Braille characters composed of six to seven dots on the back of a sheet of which they read the front with the pulp of their fingers in a sequential way). It is these control mechanisms by tactile reading that the system produced must reproduce.





2 - System configuration




The system designed by Dr. Bachy includes:

- A writing keyboard placed under the right hand comprising 8 keys, the six symbolic keys of the Sixtem code and 2 function keys


This system can operate in two modes



Normal mode :

the subject writes a text with his right hand (writing keyboard) the Apple is responsible for managing the text (transcoding, timings, etc.) the subject reads the text then sequenced with his left hand.

The learning mode : the subject sends a text stored in a file, or types it from the Apple keyboard, to the reading file. the subject reads this text with his left hand; he writes with his right hand the text he has just read; the Apple controls the operation (sends a success or error signal).

The following paragraphs focus on the normal mode.



3. "Instant control" mode.

When a blind person types a character with his right hand, he may make a typing error and want to correct it before typing the next character. It is possible to recreate the same mechanism of instantaneous control that takes place in the case of visual control.

Indeed, when the blind person wants to type a character with his right hand, he will expect the corresponding key to move under his left hand, which implies that he has acquired this "conditioned reflex" by learning. If the key that sends the tactile information corresponds to the letter he wanted to hit, the control is positive. Otherwise, it is able to erase the erroneous character and start over.

This control system is identical to the one exercised by musicians when they practice their instrument: if a pianist wants to play a "do", he thinks, he hears internally and waits for a "do" before hitting the key. If, while typing, he hears another note, he will instantly recognize his mistake and be able to correct it.

However, this instantaneous control function will not be used in the usual way. Indeed, several comments from typists and blind people have oriented our research towards a sequential mode of control: A typist only looks at the text she has to type without worrying about the one she is writing , text that it usually checks at the end of a paragraph.

The same for a blind person. The latter writes a line which it then verifies word by word, sequentially. These findings led us to develop a sequential control mode.



4. The "sequential control" mode:

In the sequential mode the subject types a series of characters which are stored in memory by the apple. The latter sends them back to the touch keyboard automatically (word by word, line by line, sentence by sentence) or on a control command sent from the touch keyboard. This mode of control implies a perfect knowledge of the code which can only result from a long apprenticeship. Once the code has been acquired, it is then truly the reading as we usually do with our alphabet.


5. The "reading mode":

It is appropriate here to develop a little the mechanisms of reading. Indeed, after learning the code, the subjects truly acquired a new way of writing and reading which conveys the language.

Not only do they assign the position of the keys under their fingers the corresponding character, but also, after a certain period of learning, they will sequence the reading of their text in words.

When we read the word "tree", we do not stop at the initial stage of our learning which consists of reading a+r+b+r+e = tree but we directly read the word tree (the meaning and understand this representation (meant)

It is the same for people who practice Morse code fluently; these no longer fix their attention on the succession of dots and dashes, nor even on the letters made up of these dots and dashes, but hear the words of the text and mentally imagine their representation.

This annotation was already studied and interpreted by the psychologist William BRYM and a former telegrapher Noble Harter in 1897 in a study on the art of telegraphers.

"These pioneers observed, from interviews, systematic observations and recordings of the work of telegraphers, that as he learned, a telegrapher assimilated increasingly long sets of texts: he began by dots and dashes, the basic elements of telegraphy then read letters, syllables, words, even sentences."

The Art of Typing Timothy Salthouse in For Science - April 1984

Also one can quite consider reading from the computer as an end in itself and not only as a control of the writing. Entering the content of a work on a floppy disk, having it read and translated by the computer which then sends the signals in coded and sequenced form to the tactile keyboard where they are then read by the individual's left hand, a business easily achievable.

Compared to books in Braille, this writing method avoids the use of huge works that can be used by only 10% of blind people. Compared to cassettes for tape recorders on which book texts are recorded, the tactile solution presents a silent and much faster solution. There is a new type of tape recorder launched by the VSC company which makes it possible to listen to a recording in a much shorter time, sometimes half the duration recording. Professor Sanford Greenberg studied and made this variable speed tape recorder when he realized that he was going to go blind, and that listening to tapes reports necessary for the exercise of his profession entailed a considerable loss of time; (a speaker cannot pronounce more than 125 words per minute, a regular adult can read about 300 words/min). Tape recorders: the accelerated or slowed voice Roger Bellone Sciences et Vie - June 1981
Thus the "reading" mode appears to be a second outlet just as promising as that of the control of the writing, the success of which depends only on the success of the learning of the code.



II - Choice of reading system

Part of this study consisted of looking for different technical solutions to make the reading keyboard. Here is a brief presentation of the different avenues that have been explored and the reasons for their abandonment or their choice.


1- Keyboard with piezoelectric elements

This physically very elegant solution had to take on the appearance shown in the diagram opposite Many difficulties led us to abandon this idea: - the extreme fragility of the PXDE5 piezoelectric elements - the low displacements or forces produced

- the importance of the electrical voltages that would have had to be produced to generate sensitive displacements, which are difficult to reconcile with safety standards.

However, the Ordi-Braille project, developed by the Language and Computer System laboratory of the Paul Sabatier University in Toulouse, included a keyboard comprising piezoelectric elements, elements abandoned for miniaturized electromagnets.

If the piezoelectric solution is not justified for the realization of a test keyboard, it nevertheless deserves to be deepened with a view to a more sophisticated application presenting other requirements.

One of the advantages of this solution is to be able to respond to a frequency-adjustable stimulation and cause vibrations under the fingertips to which the body is very sensitive (no adaptation of the sensory receptors).


2- The thermal cell keyboard

The idea consisted in using thermal heads identical to those of thermal printers which, placed under the fingers of the left hand, would have provided information by heating the pulp of the last phalanges.

This system was attractive, because using professional equipment, designed to operate quickly (heating time: 3 ms, cooling time: 8 ms), with a long life; it was discontinued for the following reasons:

- the nervous system receiving and carrying thermal information is different from that concerning tactile information and much less efficient.


3- Keypad with buzzers:

The buzzers consist of piezoelectric ceramics and a small oscillating circuit which deliver sounds whose frequency can be varied using an adequate power supply.

The sound thus produced is unpleasant and quickly unbearable and the vibration of the housing is not detectable to the touch, even at low frequencies (< 100 Hz) Indeed the idea which had led to consider this solution was to combine a reading system tactile (vibrating system) and auditory.


4- Auditory reading solution :

The idea, extremely simple to implement, consists in associating with each of the keys of the writing keyboard, an oscillator of determined frequency. This solution leads to the learning of a musical language where each character corresponds to the combination of two sounds.

The only objection that can be made against this solution... is that it makes noise. Paradoxically, it could be used in the case of deaf and blind disabled people.

The psychologists who deal with the blind are adamant: the ear cannot replace the eye; these two sense organs do not admit the same modes of functioning. The ear, organ of watch, cannot provide, like the eye, continuous attention to prolonged stimuli.

Nevertheless, the simplicity of this solution can allow its use for additional tasks: - during learning, it can be interesting to couple tactile and auditory readings to facilitate or accelerate the acquisition of the new language. - after learning according to these two modes, auditory reading could replace tactile reading so that the hand, unsolicited, can relax for a while and resume its task once rested.


5- Electromagnet keyboard:

The electromagnetic solution is the one chosen for the design of the test keyboard. The elements used are of the 802 51 19 type from Mécalectro.

                                      


The arrangement chosen so that they cause the most sensitive stimulation is shown in the figure The description of the touch keyboard is given in chapter III 3 The characteristics of these elements are given in appendix 3

This solution has many advantages:


However, these electromagnets have the defects of their qualities and in a later stage, it will undoubtedly be necessary to choose smaller, less aggressive elements and consuming less current.





VI Touch keyboard tests – various interviews`


1- Tests with indicators

The tactile keyboard was tried out, in a more rudimentary form, by about twenty people, which made it possible to draw several lessons. - For most people, the then undamped impulses were clearly sensitive, sometimes even too brutal. However, the differences in sensitivity are significant and justify the use of systems which make it possible to adjust the impulse of the electromagnets.

According to Dr. Bachy, as the subject advances in his learning and gets used to the tactile reading mode, his sensitivity to stimulation increases and the impact of the electromagnets against the fingers should be reduced. This can be done either electronically, or by reducing the stroke of the mobile armature which therefore will have a lower speed and therefore a lower kinetic energy.

The spatial discrimination of the different keys has not posed a problem for the majority of people who have experienced the keyboard, even at high speed (time between two presses corresponding to the composition of a character, ie approximately 400 ms).

These tests made it possible to verify a hypothesis formulated by Dr. Bachy, namely that learning should tend towards a vectorial representation of the typed characters. When we send the subject a character made up of a sequence of two presses and we ask him what he felt, he indicates a vector whose direction is given by the two points in contact and the meaning by the order in which the electromagnets came to touch the fingers. This vectorial language is easier to learn because it is a differential reading whose capture, transfer and interpretation by the neurosensory system is easier because it corresponds to simpler physiological processes: apprehending an isolated sensation is more delicate than for two successive sensations that the nervous system can compare to each other, which allows the sequence of two presses to form an entity corresponding to the character it represents.

This remark leads to others that should be dealt with here: the writing keyboard, in the final phase of learning, will include two additional repeat and reverse repeat keys. These keys avoid having to hit the same key twice (case of m for example) or to press two keys located on the same longitudinal axis (s). This was done to avoid two movements that are more difficult to perform and therefore last longer. Correlatively, this system avoids using in the vector representation the zero vector or vertical vectors in the plane of the plate and therefore using only oblique vectors, of different angles, which are easier to discriminate and therefore to memorize.

However, this artifice facilitating typing and memorization will not be used on the writing keyboard during the initial learning phase and a priori not at all on the reading keyboard.

According to Dr. Bachy, on the one hand the transition from typing with 8 keys to that with 10 keys is extremely easy as the practical contribution of the 2 additional keys is appreciable. On the other hand the fact of having 10 keys under the right hand is only 8 under the left hand does not present any objection on the physiological level as our nervous system is gifted for this kind of situation and for making new neuronal connections. .

As far as the direct or inverse correspondences between the two keyboards are concerned, the test results are conclusive. Indeed, the two keyboards were arranged flat in inverse correspondence (auricular ✏ inch).

Half of the respondents did not even realize that the correspondence was inverse, perhaps less natural than the direct correspondence. As for other people who noticed this particular arrangement, they assured that it did not cause them any discomfort.


2- Interviews

a- psychologist's point of view:

During a particularly interesting interview since Mrs. Y. Hatwell, psychologist at the Faculty of Grenoble, worked for 10 years with two Parisian education centers for the blind, several questions were raised.

In the touch keyboard project, reading is done by the left hand. However, we know that the information entered by the left hand will end up in the right hemisphere of the brain (because the motor commands are crossed) and therefore to be processed by the language center, which is in the left hemisphere, they It will be necessary to carry out a transcerebral transfer, the duration of which could create disorders in the understanding of language.

When blind people read a text in Braille, they use both hands, which are generally of equal skill. Paradoxically, when one allows you to read faster than the other, it's the left. This is explained by the fact that Braille reading involves the seizure of forms which finds its natural address in the right hemisphere; moreover, when the blind write, they do so with their right hand and reread with their left hand.

Thus, the layout of the reading keyboard under the left hand does not present any contraindication in principle. The most important point that emerged from this interview is what could be called: the problem of the passive hand of objects and this in a mode

movement dynamics. The success of Braille is due to the fact that the input of information, abstract objects materialized by the pins of the matrixes of the code, is carried out in the proper mode of the hand, an active mode by movement.

The principle of manipulation using the Sixtem code causes the left hand to remain static to enter information; that is to say that the left hand fulfills its role of sensor in a passive mode which is not its own mode.

Devices have been made for the blind based on ultrasonic systems intended to direct them without danger. These devices have created phenomena of rejection because the permanent stimulation of the ear is equivalent to aggression. They have been abandoned in favor of the good old cane, a natural extension of the arm.

Thus, the problem of the passive hand is one of the major obstacles that the touch keyboard project will have to overcome in order to be accepted. We can nevertheless compensate for the passivity of the left hand when reading by assigning it a certain number of active functions to perform (control, word processing, etc.).





b- Physiologist's point of view:

The most effective physiological circuits are those which preserve the analogies between the two hands, with the least possible transformations

The analogies of the keyboard, of movement, of duration are not rigorously respected: - keyboard with keys for writing, hand placed above electromagnets for reading and inverse symmetry between the two hands. - downward movement for the right hand; static position of the left hand which receives the upward movement of the electromagnets - duration of support for the right hand; duration set by the time delays of the sequences for the left.

However, the transformations carried out are not complex and therefore do not require a significant effort to establish the relationships between the gestures of the two hands.

Moreover, the absence of differentiation between the two keyboards would risk creating an identity between the objects sent by the right hand and those perceived by the left hand which could mask errors of the type: "mental confusion between the two characters".


c- Point of view of an engineer from the Ordi-Braille project (Paul Sabatier University of Toulouse):

The Ordi-Braille project aims to give the blind access to computers, it includes: - a writing keyboard (right hand) composed of six keys corresponding to the pins of the Braille code - a reading table comprising 20 matrices of 6 pins at 2 mm pitch (Braille) made up of plunger cores that are read sequentially by moving the hands.

The difficulties encountered by these researchers are of interest to our study:

 - fragility of the electromagnets, which are very sensitive to dust. In a more advanced phase, it is planned to replace the current electromagnets with smaller elements.

 - the 6-key matrices do not allow the 128 ASCII characters to be produced, an imperative that must be fulfilled by the Sixtem code, the development of which is not yet complete.

 - the Ordi-Braille project costs an exorbitant price:
 - the tactile keyboard costs about 15 kF - its use with word processing software costs 100 kF and does not even allow the management of a bank account…



d- interview with a blind engineer about a similar project:

Mr. Dumont's project consists of making a steno-braille printer and the interface that allows it to be controlled from a computer like any other peripheral.

The two studies have a large number of points in common such as control (letter by letter or sequential), learning methods, etc.

In addition, Mr. Dumont, who works mainly for deaf and blind disabled people, uses Morse code which he reads on the membrane of the loudspeaker of his computer by touch.

On the problem of the Sixtem code which, like a young first, comes to dispute its place with the very noble Braille, Mr. Dumont encouraged its development because he knows the difficulties of learning Braille. However, he advised us to go to centers for young blind people, like the one in Poitiers for example, where we would find people more inclined to try new procedures than older people who have invested a lot of time and effort in learning Braille.



3- Test and interview with blind people:

Thanks to the kindness of a couple of blind people, it was possible to carry out a test with the tactile set in its current form, coupled with the computer and to have a realistic opinion (because these people were very objective) of people to whom this project is addressed.

Here are the comments that were made during the test and the discussion that followed on the design of the touch keyboard, the Sixtem code and the learning method.

a- the touch keyboard:

The principle of the touchscreen keyboard and its construction were of great interest to these two people, who only found fault with it for a few points of detail: Regarding the perforated plate on which the fingers rest: Draw an imprint in the shape of the hand so that the blind can hold their hand more easily

- replace the 8 circular holes with 4 oblong holes so that the two electromagnets hit the fingertips well

- number and name the electromagnets to recognize them easier.


Regarding the problem of the left hand, they did not object in principle, but this problem may only appear after the learning phase, after a long time of use keep on going.

The idea of replacing tactile reading with auditory reading was mentioned. They categorically reject it; only musicians can remember long melodies.


b- the Sixtem code:

It is on this point that these blind people were the most reluctant.
One was categorical: it is out of the question for blind people to invest time in learning a new code that offers neither the guarantees nor the services of the Braille code.
On the one hand, the blind have boundless admiration for this code when they practice it.
On the other hand, assuming that from a reading point of view, the Sixtem code is also efficient, it does not offer the possibility of hardware support (this problem has been removed, the Sixtem code can be embossed like the braille code is read in the same way using the index fingers of both hands and perhaps even in the global form of the character by the most gifted).

 

The other person was more nuanced and seemed more open to other solutions than Braille (like the Optacon project which uses mini cameras for example) and encouraged research into the tactile project with the Sixtem code.


c- the learning method:

The principle of read-write feedback immediately appealed to this blind couple. Of course, the programs presented must be optimized, but the method won them over, to the point that they recommended using it to create a Braille self-learning system! It is in fact possible to combine the tactile keyboard with a writing keyboard having the configuration of those used by the blind to write in Braille (some for the blind mutilated can be used with one hand). This keyboard would send characters to the microcomputer which would transmit them to the tactile keyboard configured in such a way as to allow Braille reading.


d- conclusion:

The results of these tests are very positive as to the very principle of manipulation: the reading of the characters on the touch keyboard was fully successful, the reading feedback absolutely compelling writing. The Sixtem code, a direct competitor to Braille, was not accepted. For it to be, it would have to be simpler, more efficient and able to provide the same services than Braille.

Note: the current project of tactile reading of the SIXTEM code by an haptic interface will allow the automatic learning of the code implemented on an Arduino Mega 2560 after programming on matlab 2022a.


Elements of reflection on the Sixtem and Braille codes

The opinions of the blind couple brought water to the mill of a reflection on the Sixtem code which, during the course, had made me go through a crisis of skepticism as to its validity.

This reflection came to me when I realized that the different ideas considered led to quite similar technical solutions: writing keyboard with 6 to 8 keys under the right hand, touch keyboard under the left hand, or both hands .

What must therefore make the difference between our solution and the others: it was the Sixtem code. The design of the Sixtem code had to allow it to surpass Braille, which has already proven itself and, above all, which has been established for 50 years, something that is difficult to imagine. The arguments in favor of the Sixtem code are:

- it makes it possible to create 128 ASCII characters, something only possible with 7-point Braille - it uses simple configurations (a character is a combination of 2 presses; 1 to 7 points for Braille - it uses symbols that reproduce the graphics of the usual alphabet, which offers an appreciable mnemonic aid for late blind people - a number that could work in favor of the Sixtem code is that of blind people who practice Braille: 50% of blind people know it but only 10% practice it in fluent reading.The question is whether blind people who do not practice Braille could learn the Sixtem code.



Conclusion

The results of this study are generally positive since the assembly produced, a test prototype, made it possible to verify the feasibility of the tactile reading operation and highlighted the merits of the learning method by writing-reading feedback. and this by blind people.
Of course, the already functional touch keyboard could be improved (installation of a microprocessor to make it more autonomous) and the learning programs optimized.
This will allow the practice of the Sixtem code which we will see, in use if it can claim a place next to the "brilliant" Braille code.

As for the interest that I took in this course, already great by the realization of a manipulation crowned with success, it was multiplied by the number of areas that I had to approach to achieve the touch keyboard: electronics to do-it-yourself, from computer science to physiology and psychology!...