Design And Manufacture Of An Ergonomic Computer Pen Odeghe, O

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Advanced Materials Research ISSN: 1662-8985, Vol. 824, pp 239-245 doi:10.4028/www.scientific.net/AMR.824.239 © 2013 Trans Tech Publications, Switzerland Online: 2013-09-27 Design and Manufacture of an Ergonomic Computer Pen Odeghe, O.1,a and Udosen, U. J.2,b 1,2 Department of Production Engineering, University of Benin, Benin City, Nigeria a [email protected], [email protected] (corresponding author) Keywords: Ergonomic pen, computer keyboard, mouse, musculoskeletal disorders, Repetitive Strain Injuries (RSI), Cumulative Trauma Disorders (CTD). Abstract. A user friendly ergonomic computer input pen capable of obviating the use of the keyboard has been developed. It integrates the standard or conventional mouse functions with the touch stick input device functions. The pen-shaped input device developed can perform the normal mouse functions of scrolling and clicking together with handwriting recognition functions. From the stand point of ergonomic considerations, an input device which does not involve the keyboard and allows an operator to work efficiently is to be preferred in order to reduce the medical conditions called cumulative traumatic disorders (CTD) and repetitive strain injuries (RSI). A test set up to determine the acceptability of the ergonomic input pen using participants drawn from traditional mouse and keyboard users indicated a preference for the ergonomic computer pen. Also the average time by 15 participants to type a particular sentence containing all the letters of the English alphabet using the keyboard was 39.6 seconds, while the average time of the same 15 participants to write the same sentence using the ergonomic pen was 38.5 seconds. Introduction Douglas Engelbart, a Professor with the Standford Research Institute in Menlo Park, California, developed the first device that came to be known as the mouse in 1964. At that time, the arrow keys on the keyboard were the only ways of moving the cursor around on a computer screen, and the keys were inefficient and awkward. Engelbart made a small, brick-like mechanism with one button on top and two wheels on the underside. The two wheels detected horizontal and vertical movements and the unit was somewhat difficult to maneuver. The unit was linked to the computer by a cable so that motion signals could be electrically transmitted to the computer for viewing on the monitor. One of the Engelbart’s co-workers thought the device with its long cable tail looked something like a mouse, and the name stuck. Other scientists, notably those at the National Aeronautics and Space Administration (NASA), had also been seeking methods of moving cursors and pointing to objects on the computer screen. They tried steering wheels, knee switches, and light pens, but in tests of these devices versus Engerlbart’s mouse, it was the mouse that was selected. By 1973, the wheels on the mouse’s undercarriage had been replaced by a single, free-rolling ball and two more buttons (for a total of three) had been added to the top. The creature was called both a mouse and a pointing device, and was combined with Alto computer, one of the first personal computers. The Alto had a graphical user interface (GUI). That is, the user pointed to icons, or picture symbols, and lists of operations called menus and clicked on them to cause the computer to open a file, print and perform other functions. Various input devices have evolved over time, like the mechanical mouse otherwise called “ball mouse” invented in the early 1970s by Bill English, while working for Xerox. The optical mouse was introduced in the 1980s and it came in two different varieties, some of such are those invented by Steve Kirsch of Mouse System Corporations, and the touch pad input device commonly used in laptop computers. Beside these broadly classed input devices mentioned above, manufacturers over time produced other types of mouse but still using the technologies mentioned above, like the hand shoe mouse, optical trackball mouse, Evoluent vertical mouse etc. with all claiming to be ergonomic. Although, the wireless and USB Penclic mouse and the Wacom computer pen exists in the category of computer pen, the Penclic pen mouse does not come with any software for writing while the Wacom pen is a tablet device meaning it has its own surface provided for the pen to write on [1]. The ergonomic pen developed here can write on any surface. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.ttp.net. (#69788666, Pennsylvania State University, University Park, USA-16/09/16,16:52:14) 240 Advances in Materials and Systems Technologies IV In addition, Kotani et al [2] in their study wrote about subjects with no prior experience with pen tablet usage performing better (in terms of speed and error rates) with a pen tablet system than a traditional mouse after second day of use. Pen tablet usage also reduced overall muscular activity in the arm, resulting in confirmed reduction of muscle stress in that area of the body. Also, Hedge and Chao[3] in their publication compared two pen mouse designs with a conventional mouse design in a laboratory experiment. Sixteen people (8 men; 8 women) used each of the mice to perform a series of tasks. Wrist posture was measured while hiding each mouse. Results showed the pen mice decreased ulnar deviation and wrist pronation, the latter being more reduced for women. However, wrist extension was lowest for the conventional mouse. Muller et al [4] did an experimental study to compare a pen to a computer mouse as an alternative input device while taking learning effects into consideration. They had 20 subjects perform a test program (single/double click and drag/drop) with each device for five consecutive days with performance and time to complete the tasks measured. Again the pen showed significantly greater improvement in performance. A study to investigate the Wacom computer pen and tablet versus a standard Microsoft mouse on wrist posture measured by extension, flexion, ulnar and radial deviation and compared across three independent variables: repetition, input device and session by 20 experienced users when analyzed showed less extension found using the pen than the mouse amongst other inferences [5]. To corroborate further Hedge et al [6] performed an investigation on cursor positioning task performance and on wrist posture using five different optical mouse designs including a conventional mouse, angled mouse and vertical mouse, with a pen mouse representing the slanted design and summarized that performance and posture were affected in opposite ways by these different mouse designs.. And overall, an adjustable-size slanted mouse design may offer the best combination of neutral posture and performance. However, there are many health problems associated with this combination such as Cumulative Trauma Disorders (CTD) or Repetitive Strain Injuries (RSI). Prolonged use of conventional keyboards have resulted in cumulative trauma disorders also referred to as repetitive strain injuries due to awkward postures maintained, while performing repetitive typing motions [7]. Researchers have pointed out that the QWERTY keyboard causes the typing to be poorly distributed between the hands such that the weaker ring and little fingers are overworked. Ergonomic designing of keyboards seeks to protect the user against these injuries as well as making keyboards comfortable and easy to use [8]. Right from early age, the normal way human beings are taught to write is by using the chalk, pencil or pen. Human beings are therefore accustomed to the pen instead of the keyboard and mouse. It is quite possible to dispense with the keyboard and mouse by using the ergonomic computer pen as a pointing as well as an input device. This is the major objective of this work in order to eliminate the musculoskeletal health hazards associated with use of keyboard and mouse. The word ergonomics comes from two major Greek words ‘ergon’ and ‘nomos’ meaning the law of work. It aims at improving working environment, reducing operator’s fatigue and strains and increasing the efficiency of the manufacturing organization. It is basically the study of the relation between man and his occupation, equipment and environment and particularly the application of anatomical, physiological and psychological knowledge to the problems arising there from. It covers a very wide field, and it is usually applied at the initial design stage when production lines and workplaces are being laid down. It may also be applied to improve an existing layout or design. Ergonomics is generally known as the science of fitting the job to the worker. Every equipment, tool etc., designed for any activity should take into cognizance the capabilities and limitations of man [9]. Ergonomics supply the principles and techniques for achieving this objective while catering for peoples’ safety and comfort. Ergonomics principles were applied in the design of this ergonomic computer pen. It was designed to fit the pen to the man and made easy to use, whereby a secretary can take notes with the pen and obtain both the hardcopy and electronic or softcopy because the pen incorporates computerized handwriting recognition functions. Advanced Materials Research Vol. 824 241 It has been shown that there is correlation between computer work and the occurrence of serious health complaints due to prolonged working with the mouse [10, 11]. The use of a pen is said to be less physically tasking, and the wrist position is more neutral and consequently better [12,13]. In addition, the muscle stresses in the forearm are 2-5% lower than when using a standard mouse Alternating between the mouse and the keyboard is not an easy task. For users who work with a mouse for prolonged periods, such as web designers or graphic designers, pens are a very good solution. From the foregoing, this design of an ergonomic pen capable of being used as a mouse as well as an input device in place of a keyboard is therefore justified. Methodology This research work is basically divided into two parts, the mouse function and the handwriting recognition function. Some of the important components used for the design and construction of the pen representing the mouse include: Resistors; Capacitors; Diodes; Oscillator; and Micro Controller IC. The component which needs a description is the micro controller integrated circuit (IC). Micro Controller. An Integrated Circuit (IC) is a small microchip that contains a large number of electrical connections and performs the same functions as a larger circuit made from separate parts. Then the micro controller is that I.C or microchip which permits a set of computer codes or programs to be downloaded into it to carry out a particular task or function. For the purpose of this work, the PIC 18F4550 micro controller was used. The codes in the micro controller monitors the four inputs that describes motion for up, down, right and left movements of pointer or cursor. Four small copper strips connected to appropriate pin legs of the controller are aligned on the four walls of the pen shaped casing so that when the stylus material presses against them, it describes the motion of the user’s hand. As the user moves the stylus over a surface, the stylus presses against these metal plates, and the circuit detects these plates action and initiates the recording and transmission of this information to the PC via the USB connection (using USB communication protocol) to effect the cursor movement on screen. The micro controller has internal registers it assigns for monitoring the four direction plates. When the stylus presses against any plate during movement, the controller increments count of the assigned register and this count is proportional to the intended distance to be covered or distance covered. This information is then processed into the communication data packet and then transmitted to the PC. This monitoring is for all directions typically, right, left, up and down. Two types of the ergonomic pens were developed, one using metal strips for contact as described above and another using an optical sensor. Figure 1 depicts the ergonomic pen with an optical sensor. The pen controller system consists of the optical sensor and the micro controller 18F4550. The optical sensor stage consists of the sensor and the LED to illuminate the surface on which the pen is scrolled. The optical sensor is a CMOS 0M10B type or an A2636 variation. The optical sensor has a camera-like lens used to scan surfaces and extract movement information by comparing successive picture frames of the surface and then processes the information to the direction and distance moved. This is sent out to the micro controller serially. The micro controller in turn receives the data and extracts the movement/displacement information of the X/Y axes and then sends the data to the PC (which is the Host). The micro controller unit checks for button states too before transmitting it to the PC. A test was carried out to compare the ergonomic pen developed with an input device already in existence, viz. the computer keyboard. A sentence containing all the English alphabets given as:“THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG ON THE GROUND”, was used in the test. The subjects used the ergonomic pen to write this sentence in a computer program developed using C++ computer language and the times to write an error free sentence were recorded. There after the same subjects also used the QWERTY keyboard to type the sentence and they were timed and the comfort ratings presented in Table 1 were employed by each participant to assess how comfortable he or she felt using the keyboard compared with the ergonomic pen. The 242 Advances in Materials and Systems Technologies IV results were then plotted in the histograms presented in Figure 2. Figure 3 depicts the times obtained by a participant using the keyboard and ergonomic computer pen repeatedly ten times. The times obtained are presented in Table 2. 2cm Power indicator 17cm USB cable Right click button Body Left click button USB connector Pen Figure 1: Ergonomic mouse with optical sensor Advanced Materials Research Vol. 824 243 Table 1: Comfort rating table Extremely comfortable Very comfortable Comfortable Fairly comfortable Not comfortable 5 4 3 2 1 In a test involving fifteen participants using the keyboard (to type) and the ergonomic pen (to write) the document in question, the times presented in Table 3 were obtained. Table 2: Keyboard and Ergonomic Pen Repetitive Times 56 53 51 50 48 47 46 43 40 38 Ergonomic Pen Times (sec) 1 2 3 4 5 6 7 8 9 10 Number of repetitions Table 3: Times (seconds) of 15 subjects using Ergonomic Pen and QWERTY Keyboard 59 57 54 53 51 49 47 46 44 41 1 2 3 4 5 6 7 8 9 10 Keyboard Times (sec) Number of repetitions Subjects 10 11 12 13 14 15 Mean 48 50 49 32 40 53 42 38 37 31 26 34 33 41 24 38.5 Keyboard(sec) 58 39 51 30 43 57 44 40 39 37 29 36 33 30 28 39.6 Pen(sec) 1 2 3 4 5 6 7 8 9 Discussion of Results From Figure 2, it is noteworthy to mention that not all the participants agreed that the ergonomic pen was comfortable in usage. The results indicate that a more efficient inputting method to the computer can be obtained using the ergonomic pen. Figure 3 presents the times obtained by one participant repeating the test ten times using the keyboard and the ergonomic pen. The result shows that the times obtained using the ergonomic pen were lower that those of the keyboard. Reduction in the time required to type a document has many advantages. Studies have shown that prolonged usage of the computer keyboard can cause cumulative trauma disorders (CTD). It is therefore pertinent to minimize the duration of typing or better still, write with the ergonomic pen to eliminate this health hazard. It is for this purpose that the ergonomic computer pen presented here should be applied. The simple test carried out as mentioned above revealed that some participants in the test wrote the words faster using the ergonomic pen than others who used the computer keyboard. In another test involving 15 participants presented in Table 3, the mean time obtained when using the ergonomic pen was 38.5 seconds compared to 39.6 seconds for the QWERTY keyboard. This is an indication that the pen may be easier to use than the keyboard. 244 Advances in Materials and Systems Technologies IV FREQUENCY KEYBOARD AND ERGONOMIC PEN COMPARED USING COMFORT RATINGS 14 12 10 8 6 4 2 0 Series1 KEYBOARD 1 2 3 4 Series2 5 ERGONOMIC PEN COMFORT RATINGS Figure 2: Comfort ratings of Keyboard compared with Ergonomic Pen KEYBOAR D 70 60 50 30 20 TIMES(SEC) 40 ERGONOMIC PEN 10 0 1 2 3 4 5 REPETITIONS 6 7 8 9 10 Figure 3: Graph depicting the ergonimic pen times slightly lower than the keyboard times. Conclusion An ergonomic pen capable of being employed as a pointing device and as an input device has been developed, tested and applied. In a test carried out to compare the ergonomic pen developed with an input device already in existence, viz., the QWERTY keyboard, the participants agreed that the ergonomic pen was comfortable and the times obtained when writing with the pen were found to be lower than times from typing with the computer keyboard. The ergonomic pen will no doubt prove to be a very useful device which will eventually obviate or supplant the use of computer keyboard as an input device. In another test performed by fifteen participants, using the pen and keyboard, the mean time computed for using the pen to write a document was found to be 38.5 seconds and was lower than 39.6 seconds obtained when typing the same document with a QWERTY keyboard. This is an indication that the ergonomic pen is to be preferred as the faster input device. Advanced Materials Research Vol. 824 245 The ergonomic pen has the advantage of minimizing CTD caused mostly by keyboard usage. The human body has the ability to adapt and acclimatize to poor conditions, even poorly designed input devices. This notwithstanding, there is also clinical evidence of finger, wrist, neck, back and shoulder joints of keyboard operators with marked flexion, extension, abduction and deviation due to prolonged operations which force the joints into unnatural postures resulting in pains. Also physiotherapists and osteopaths have observed that keyboard operators provide them with a large occupational patients group. Since the introduction of computers, RSI has been reported and is experienced from repeated exposure to doses of strain by keyboard operators who perform over 10,000 keystrokes per hour resulting in swelling of the hands and wrists. This undesirable occupational health hazard is bound to increase in future, but luckily the ergonomic pen which incorporates computerized handwriting recognition functions has been developed to replace or minimize keyboard usage. References [1] S. Zhai, The Computer Mouse and Related Input Devices. 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