Assertive Technology For The Physically Impaired Computer Science Essay

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The 21st century is the century of the computers. People from all walks of lives need to learn how to use computers as most of the things around us required at least some basic knowledge of the computer. Somehow, for perfectly normal people like us, it is a piece of cake to adapt to the evolving technology.

As we look around the street, have we ever thought of those unfortunate people with disabilities? What about their difficulties in utilizing the computer? Of course, we might say that the number of the disabled people is minority compared to us. Some people even look down on these ill-fated people because they think that these people will not offer useful contribution to the society.

Therefore, it is unbelievably thoughtful for some companies that bring to mind the existence of unlucky disabled people. There are a few categories of disabilities - mobility impairment, visual impairment, learning disability, hearing impairment and etc. All these disability is not severe enough to affect the usage of a computer. Those companies created special devices to assist the disabled people known as assertive technology. Thus, it had made their lives easier in coping with the advancing technology.

For the purpose of this assignment, our group focuses on assertive technology for the physically impaired.

Examples of Assertive Technology:


Head-Controlled Computer Access

" What is a HeadMouse? "

A HeadMouse is a wireless optical sensor which tracks a tiny reflective target(dot) which is usually placed on user's forehead. The HeadMouse translates natural movements of a user's head into directly proportional movements of the computer mouse pointer. It works just like a normal computer mouse. The reflective dot can also be placed on any parts of the body-arm, fist, foot-whereever it has the best movement. The mouse cursor is controlled by the user by moving his head. HeadMouse replace a conventional mouse for the handicapped. HeadMouse gives a wide field-of-view and greater accuracy. It supports graphic-intensive applications and Computer Aided Design(CAD). The HeadMouse is a very small, lightweight, fast and low powered optical head pointing device which fully emulates all mouse movements.  It is powered by the host device (either computer or AAC device), draws extremely little power and connects to a USB.

<<<=Tiny, flexible and paper tracking dot placed on forehead.

Objective :

To provide a mechanism of interaction and low-cost alternative for people with reduced mobility or pointing problems that cannot use an ordinary mouse especially the handicapped.

" How does a HeadMouse works? "

The HeadMouse must be first connected to the computer or augumentative communication device through a USB port and operated using standard mouse drivers. The HeadMouse is powered over the USB connection.

When the user moves his head(or any part of his body tat the reflective dot has been placed), the movement of the HeadMouse is recognised by an infared receiver which in turn translates the head movements into cursor movements on the screen. In addition to cursor movement another element is required for full mouse functionality that is button clicking. Mouse button selections are made either by using a dwell and click software application whereby the user pauses over the on-screen target for a user definable period of time, at the end of which, a pre-defined button click (left, right, double left, click and drag, scroll) is generated. Alternatively, clicks can also be generated using a physical external switch (link to switches) that can be activated by fists, fingers, arms or foot.

Advantages to the handicapped :

The HeadMouse is the latest technology which is designed especially for the handicapped. They don't need to use their hands to control the computer mouse as the HeadMouse can be controlled by placing a tiny reflective target or a reflective dot on the forehead of the user and using the user's body movements to control the HeadMouse. This would be much more convenient or those who are handicapped.


" What is a keyguard? "

A keyboard keyguard or keyguard is a plate with computer key-sized holes that is used to place above the keys on a standard keyboard. The keyguard is resistant to pressure due to its stiffness. It is usually made from metal or unbreakable, clear, thick Lexan (a plastic material).

The history of the keyguard was originally developed by a form sixth student who is inspired by a man whose hands trembled too much for him to that unable him to type.

" How is it used? "

Keyguard was developed for those whose hands trembled too much, or with tremors and athetoid conditions, that give them difficulty in typing on the keyboard, where they tend to hit a series of unwanted keys as they are typing. When the keyguard is placed on the keyboard, users with difficulties particularly in the hand area will not face trouble when typing words with a keyboard. This is because the holes in the keyguard are made to protect, or in other words covers the keys that are not used in case if a physically impaired (in their hand) user need to rest, the user can rest their hands on top of the guard while typing and therefore reduce strain on the upper limb due to tremor or muscle weakness in their hands.

Types of Guard

There is no standard-sized computer keyboard. There are small differences between hundreds of keyboards for instance, spaces between keys, shapes and types of keys, and even its size. This means that it might be difficult to get a keyguard to fit any given keyboard. Fortunately keyboards are very cheap in compare to the keyguard, so it's usually best to buy the two devices together to make sure that they fit.

Keyguards can also be use with other specialist keyboards such as the IntelliKeys (programmable alternative keyboard that plugs into any computer) and BigKeys (standard push-button keyboard but with bigger keys), and even detached numeric keypads.

Big keys


Intellikeys Keyboard

Advantages and Disadvantages

There are some advantages when using a keyguard for instance, Even though the keyguard was originally developed for people with tremors and athetoid conditions; it has also proven to be a successful tool for people with muscular weakness difficulties. In this case, the user can rest their hands on top of the guard while typing and therefore reduce strain on the upper limb. This also means that keyguard can be used for everyday users and does not apply only to physically-disabled users.

Some of the disadvantages when using a keyguard are; the users are unable to type fast. This is because the holes are on top of the keys of the keyboard, which involves lifting up their hands every time to touch the keys that are located under the holes. Therefore, it is required to type one button at a time. Nevertheless, there is a solution to this matter. The user could install Word Prediction software such as Co: Writer or Penfriend, that able to complete the words that are intended to be type, by just typing a few words as a start. Other than that, keyguards are not applicable to laptop computers. One reason for this is that laptops and their keyboards defers in layout, size, and shape. Other than that, laptops might not be such as a good idea because the screen on a laptop is attached to the keyboard, these results in a poor ergonomic set-up that could contribute to neck pain. As a solution to this matter, users can purchase a portable keyboard for the laptop such as the Compact Keyboard, and adding a guard to it.

Voice Recognition

Recognition systems that must be trained to a particular speaker, as is the case for most desktop recognition software.

Recognizing the speaker can simplify the task of translating speech. Speech recognition is a broader solution which refers to technology that can recognize speech without being targeted at single speaker, such as a call center system that can recognize arbitrary voices. The aim of the technology is for a two-way purposes, firstly is easy to control of various home appliances by voice, and the other is to enable severely disabled person's movement independently using voice activated powered wheelchair. The voice activated home appliances control system works out through a few follow-up process, in which firstly, the speech input device is can be use not only headset but also mobile telephone via Skype Voice of IP (VOIP) module.

At first, the microphone captures the speech signal. The incoming audio stream is then segmented for recognition using the VAD module. The stream is transmitted from speech interface to the recognition engine where the recognition procedure is carried out. Our recognition engine employed a Julian decoder (Lee at al., 2001) with mel frequency cepstral coefficient and adapted a speaker-dependent acoustic model. Finally the recognition result is executed when results are satisfied with voice using V/NVclassification module. By using the result of speech recognition for infrared remote control, system can be remote control powered wheelchair and home appliances including TV, radio, VCD/DVD player, lights, and fan. System is also offers hand-free management of telephone calls and direct calling to family through one voice command. Software is designed and developed under the visual studio platform and using visual C++ programming, which can be installed and run in Ultra Mobile PC (UMPC) under operating system of embedded windows.

A voice controlled Graphic User Interface (GUI) is carefully designed for disabled person in the Fig 1. By clicking on one of the icon on the user's screen or voice command directly correspond to the environmental commands like switching on the lamps, starting the Radio, calling the facilitator. Also, wireless microphone or mobile phone can be used instead of wire headsets for user's convenience.

Fig. 1. Example of system GUI design. (a) Powered wheelchair mode. (b) Home Appliances Control Mode. (c) Sub Control Mode ( TV, Audio, Phone)

The developed system consists of a headset, a Pentium M 1.2GHz UMPC, infrared

<< Fig. 2. Prototype powered wheelchair.

The voice commands to control wheelchair direction are not easy when use the minimum number of commands.

transmitter for long distance transmission and a wheelchair controller, as is depicted in Fig. 2 below. Also, wireless microphone or mobile phone can be used instead of wire headsets for user convenience


Computer technology has gradually increased over the years. Special devices for disabled people have made their lives more convenient in accessing and utilizing the computer. It is captivating to see those disabled people and their strong will in fighting to be known as "normal" to us. Everyone wants to be extraordinary, differ from others and exclusive in their own way but these people are in fact poles apart from us. They want to be treated equivalent and crave to lead an ordinary life.

Hopefully assertive technology continues to develop consistently in the near future so that the improvement of technology in computer will cease more of the inconveniences for these people.