PROCEEDINGS of the HUMAN FACTORS SOCIETY 33rd ANNUAL MEETING—1989

DATAHAND*: DESIGN, POTENTIAL PERFORMANCE, AND IMPROVEMENTSIN Till-; COMPUTER K E Y B O A R D AND MOUSE

Leland W. KnightAssoc. Professor, Dept. of Design, Arizona State University

Dale RetterIndustrial Innovations Inc.

ABSTRACT

This paper presents the design and preliminary evaluation of a new computer key and spatialentry system called Datahand. It is intended to improve human-to-computer data entry and control, aswell as providing possible reduction of five major identifiable problems with conventional keyboardswhich subject operator to injury. The overall physical form of this product, its keys, and their organi-zation, are unique in shape and function. Such a departure from traditional keyboards has presented anopportunity to consider new approaches to hand position, key design, spatial control and function.Preliminary empirical results from first users are covered in this paper.

CONCEPT

Introduction

The ideas that became the determinants which wereto form the basis of the Datahand concept grew out of prob-lems encountered while using conventional keyboards.These problems fall into two general categories, a need torethink the tools of computer interfacing, as well as thosefunctions that affect speed and accuracy. Electronic pro-cessing has significantly changed alpha numeric input asspeed and accuracy have been affected by the addition offunction keys and (ten) key pads to the keyboard. It is stan-dard to have 101 keys, or more, in today's electronic key-boards. In addition, many entry devices use a mouse.These changes have denigrated the concept of home keys,and require the user to move the hands and fingers over amuch larger area of control, thus adversely affecting speedand accuracy. In addition, the ergonomics associated withprotracted use, such as word processing and repeated use ofkey entry pads, bring physical and mental stress and are po-tentially capable of physical damage to the user.

System Concept

Datahand looks different, works differently and re-lates to the user in a different way from its predecessors. Aseries of demonstration models were developed. Each modelwas carefully studied and compared with previous designs -until an overall configuration was defined that met the hous-ing needs of the various components and the operationalneeds of the user, Fig.l. By splitting the keyboard into twoseparate components, a left and right unit, the user's handsare brought to the keys which are wrapped around the user'sfingers, as opposed to a conventional two-dimensional key-board. Each unit contains a mouse funcnon thus eliminatingthe need for a separate component. Datahand is a plug-com-patible replacement for both the conventional keyboard andmouse. Each unit (hand), Fig. 2, can be divided into five ar-eas regarding the type of function to be addressed: (1) athumb pocket that is recessed to hold the thumb and sixswitches, (2) four finger holes each containing a five-way-switch, (3) palm support, (4) a key

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assignment viewing screen, and (5) a mouse function, con-tained in each unit The individual shapes that are broughttogether into a single hand unit are carefully developed tomeet their particular area function, and work in conceit withother shapes that make up a right or left hand unit Each unitis free to move in anoc andy motion for cursor control Theleft and right units can be separated, while in use, to allowspace for reference material.

The result is that the product system is more compati-ble with the human system, allowing for a more naturalmatching of human and machine. By providing a separatehand support and key function for each hand, individual dif-ferences in hurnan hand, wrist, and forearm can be better ac-commodated. |For example, arms do not have to be held a^equal length to reach keys. As a; totally new product system,each component of Dntahand is specifically shaped, not onlyby its particular needs, but by other features mat interact withit The physical shape and organization of Datahand isunique in that it uses a three-axis approach to die entry func-tion. Other designers, in attempting to improve on the key-board, have used standard switches which in effect has lim-ited function to two dimensions. The emphasis is on shapingthe product to meet the needs of the user. This can only bedone by considering the total needs of the system and beingcommitted to making changes where necessary. Key as-signments have been designed with a maximum overlap withstandard QWERTY finger movements so that minimal re-learning is required by the user.

HUMAN FACTORS IN DESIGN

It must optimumly perform an the intended require-ments of utility. -User function should be defined and en-hanced by the effective use of human factors needs. Thepurpose and meaning of the product should be reflected by itsappearance; that is to say, the organization and supportingfeatures of a product should be shaped to visually conveytheir function (product semantics). A significant humanfactors concern is not just performance but the ease of learn-ing.

The Hand Units

Each hand unit has a contoured palm and hand sup-port making it more" comfortable, and also graspable so that itcan be easily moved for mouse control. Bom units incorpo-rate a mouse function (underside motion detection device).Mouse input is achieved by moving the entire right or left unitwithout removing the hands from the keys. Prototype unitshave been developed with a provision to allow palm supportto be configured to the needs of the individual user hand sizeby the addition of shells to the pahn support.

The actual prototype is shown in Fig. 3 and is a fully-functioning model.

DATAHAND KEYBOARD

LEFT DATAHAND RIGHT DATAHAND

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PROCEEDINGS of the HUMAN FACTORS SOCIETY 33rd ANNUAL MEETING—1989

Thumb and Finger Kevs

Datahand electronically layers its keys in three modes:Normal, NAP, and Function. The standard keyboard's 4throw keys are in a new mode called the NAP (Numeric &Punctuation) Mode. In this mode, the numbers become theunder-finger keys, and the keys above them become thepunctuation keys, Fig. 3.

The circular key caps in Fig. 3 represent the keys atthe bottom of the key wells. The square key caps clusteredaround each circular key cap indicates the keys which are ac-cessed by forward, backward, left or right movement of thatfinger.

Datahand employs finger movements almost identicalto a standard QWERTY keyboard, so that little releaming isrequired. The illustration, Fig. 4, indicates the closerelationship of Datahand finger movement to the standardQWERTY finger movement.

With QWERTY With Dotahand

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The present design provides for a large illuminatedcolor multiplexed display to be located above the fingers.Above each finger is a schematic depicting the keys that eachfinger can activate.

The thumb is mechanically and neurologically the most ver-satile and powerful digit on the human hand. With a conven-tional keyboard, both thumbs together share the space bar,providing no other routine inputs. With Datahand, keys areclustered about the thumb joints and tips such that sevenJccyimay, by distinctly differing motions,- beHOperated. Thuswith Datahand, the thumbs control 14 data erhry keys. Thisis an interestingly similar repetition of early human factorswork wherein aircraft pilots' use of finger switches wassignificantly improved upon by transferring control functionsfrom fingers to the thumbs.

Spatial (Mouse) Input

A. Vernier mouse control could be added to all appli-cations (presently employing a mouse) with no software orhardware alteration. This is accomplished by making onehand's motion a coarse mouse control and the other a finemouse control.

B. Simultaneous two point screen'control is possible.For example, each of tv.o diagonally opposite comers o!' arectangle could be separately controlled by a left and rightmouse device. This would give simultaneous control overboth size and location in a graphics or CAD type application.This same selection method could enhance text selection in aword processor or field selection in a spreadsheet application.

C. Simultaneous three dimensional control for 3D,graphics, CAD and other applications. Use of the left hand toinput a "Z" axis coordinate together with the right hand'sexisting "X and Y" axes input would make this easy and in-tuitive.

Keyboard Caused Iniurv

There are 5 major identifiable problems with conven-tional keyboard data entry systems which subject operators toinjury as follows:

Problem #1: A conventional keyboard requires the wrist tobe bent This creates muscle stress, compresses the carpaltunnel and median nerve (through which finger-controllingtendons and median nerve pass), increases the friction onmoving tendons by causing them to bend, and stretches thefinger tendons. Datahand attempts to reduce these problemsby allowing an operator's wrists to remain straight.

Problem #2: A conventional keyboard requires the opera-tor's hand to maintain a flattened profile. This places con-stant tension on the finger muscles and tendons; it also re-quires a less-than-optimal angle of key actuation. Datahandallows the hands to remain in a natural relaxed position withthe fingers comfortably curved. It was designed around ahuman hand in the most relaxed position.

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PROCEEDINGS of the HUMAN FACTORS SOCIETY 33rd ANNUAL MEETING—1989

Problem #3: A conventional keyboard requires the operatorto constantly support the hands and arms floating above thekeys. This creates constant muscle stress in the hands, arms,shoulders and neck. Datahand provides built-in palm restswhich completely support the hands and arms.

Problem #4: A conventional keyboard demands that anoperator maintain one single operating position for his or herhands and arms. This prevents variation in the muscle, jointand tendon loads. Datahand allows the operator's hands tomove about independently.

Problem #5: A conventional keyboard requires consider-able ergometric work to actuate the keys. Since a conven-tional keyboard's only operator support is achieved by par-tially resting the fingers on the keys, the keys must be stiffenough to prevent inadvertent operation. Also, since a con-ventional keyboard requires fingers to traverse longdistances, the fingers must travel so quickly that fingertip im-pact is appreciable and requires a lengthy key travel to par-tially cushion die shock of impact With Datahand, fingertravel is only a few millimeters and because the hands aresupported through the palms, the keys can be much moresensitive, have less travel, and therefore require lessergometric work.

EARLY SUMMARY AND EXTRAPOLATION ONFIRST CONVERSION LEARNING CURVES FOR

TOUCH TYPISTS LEARNING DATAHAND

Findings

At this point only two controlled "conversions"(where experienced QWERTY typists learn to type utilizingDatahand) have been undertaken. These two operators arcboth thought to be above average in motivation, openness tochange, learning speed and manual dexterity. This is basedon their willingness to participate in this study out of enthusi-asm for Datahand with no or minimal monetary payment.Subject #1 tests at 49 wpm on a conventional keyboard andsubject #2 at 54 wpm. The prototype utilized for these pre-liminary tests operates significandy below the performancelevel expected for production models.

After 9 sessions totalling 13.2 hours, an averagespeed of 32 words per minute with an accuracy of 99.% uti-lizing 26 characters, was obtained by the first subject Thesecond operator after 14 sessions totalling 16.8 hoursachieved an average speed of 35.7 words per minute with anaccuracy of 98% utilizing 29 characters. Both operators'performances were very close to each other when adjusted forpractice time.

Discussion

• Although these arc the first preliminary results fromour first empirically quantified study, it appears that Datahandcan be learned in a relatively few hours. How many practicehours will be required for operators speed to equal or exceedtheir standard key- board speed is not yet known. If Data-hand will be faster and more accurate is not yet known.Likewise, it is not known if the potential medical advantagesof Datahand will be realized in actual operation.

13 DATAHAND Speed as a % of StandardKeyboard Speed

Q Cumulative Hours Practice

•*- Number of Characters in Use

•o- Average Speed with DATAHAND

40 Keysor WPM

30 KeysOf WPM

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Practice Sessions

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PROCEEDINGS of the HUMAN FACTORS SOCIETY 33rrl ANNUAL MEETING—1989

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Respecting both graphs, the values for the columns readon the left axis. The darker bars represent Datahandtyping speed as a percentage of the subject's averagetyping speed on a conventional keyboard. Speed mea-surement for both Datahand and conventional key-boards was made with Typing Tutor IV (Simon & Schus-ter Software by Kriya Systems, Inc.. version I.2). a com-puter based software application which administers andcomputes typing speed. This application was used asthe training program for typists learning Datahand.

The lighter lower columns represent the cumulativenumber of hours spent learning Datahand (time kept bythe computer) and the values are read on the left axis inhours (Hr.)

The line connecting the dark data points represents thenumber of keys the typist is employing during each prac-tice sessions and the value is read on the right axis. Theline connecting the light data points represents theaverage speed in WPM achieved using Datahand, aver-aging all speed tests taken during each session. Allspeed tests averaged better than 98% accuracy.

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Conclusion

It is hoped that this preliminary report will induceothers within the human factors discipline to undertake moreadvanced comparative studies of the device.

*Datahand is a trademark of Industrial Innovations, Inc.,Scottsdale, Arizona, U.S.A. Patents are pending. All rightsare reserved. Keyboard Assignments arc Copyrighted©1989 by Industrial Innovations, Inc.

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