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Computer technology in the classroom Meldreth Manor School

Physical Access

One major difficulty in providing access to computer technology to pupils with SLD/ PMLD is that of enabling physical access for people who cannot use the conventional keyboard or mouse. There are several alternative input devices ranging from modified keyboards, joysticks, trackerballs, concept keyboards, touchscreens and switches. An assessment of the pupil by a multi disiplinary team is important to provide an accurate assessment of need which then forms the basis for providing an appropriate interface or link with the technology. This then forms the basis of a continuous process of review and reassessment for the pupil.
The aim in assessing a pupil for physical access is to find a reliable, repeatable and comfortable access system to the computer. With SLD an PMLD pupils this is usually via some kind of simple on/off switch. With pupils with associated physical disabilities such as cerebral palsy this is further complicated by complex physical considerations.
There are, however, some general principles that can be applied when considering physical access;
i. The movement chosen must be large enough to operate the switch without too much effort from the pupil.
ii The movement must be consistent (or capable of becoming so).
iii The movement must be capable of being isolated (it should not be reliant on an action that causes the pupil to go into spasm).
Pupils with physical difficulties usually tire easily so it is important that the action must not be too physically difficult and that there is a good rest position that the pupil can relax into after operating the switch. The switching movement should be a positive action (for example in using an elbow switch it is better to use a pushing movement than having the switch sprung so that it operates when the pupil moves his elbow away). There should be adequate feedback so the pupil knows when he/she has operated the switch, this is most important when the purpose of using the computer is to develop the principles of cause and effect. This feedback can be tactile, visual or auditory. Most press switches have a degree of travel (tactile) and a click (auditory), however when using touch switches or other capacitative type switches this feedback is often missing. It can be supplied by using auditory/ visual feedback from the computer, or by using an inline buzzer or light (a buzzer which connects between the switch and the computer and makes a short noise when the switch is operated). Finally the pupil must be happy with the access method, this may include some cosmetic work to make the switch more visually acceptable.
From an assessment of physical access to the computer the following will be decided:
1. The switch or switches that will be used with the pupil and their position (if the correct type of switch is not available commercially we will make one to fit his/her needs precisely).
2. The position the pupil should be in to use the computer, this could be in a standing frame, sitting in a wheelchair, side lying on a wedge, sitting in a chair (normal, armchair, ladderback). The seating of pupils is especially important, as a general rule if a pupil is having to think about, and work at at positioning himself then he/ she is incapable of attending to any other task, such as using a computer.
3. Specific sensory needs of the pupil. This will dictate the screen position, the colours used on screen, the size of display, any colours needed to highlight the switch, the auditory response (perhaps the use of headphones or vibration), and the tactile nature of the switches (perhaps covered in a material such as fur etc.).
4. The level and type of program to be used (within our software progression) in addition to setting precise goals for the individual in using the computer.
5. Some general guidelines on the times of day when computer use is best and the length of time the pupil should operate the computer.
6. Any specific language to be used and the approach to the pupil.

Switch mounting and positioning
The mounting of the switch mechanism is a further consideration. At the simplest level the switches need to be positioned so that they are useful (bearing in mind the earlier points on functionality, rest position, movement and spasm). Possibly the most common position of switches is on a pupils wheelchair tray or table. Switches mounted on wheelchair trays can be built into the tray so that they are just flush with the surface and can be used with an imprecise hand movement. The overall function of a wheelchair tray also has to be considered. Are the switches going to limit the usefulness of the tray for carrying items or a rebus board if the switches are permanently attached ? An idea is to mount the switches on a thin hardboard sheet which is positioned on the tray and can be removed completely when it is not needed, this also allows the wires to be hidden.
An easy way of mounting switches is to put some self adhesive velcro on the switch and cover a board with velcro active material, the switches can then be easily positioned and changed. hardboard squares can be covered in this material. Some degree of flexibility and adjustment are often needed when making head switches, so that throughout the day can be allowed for.

Switch Access


Switch Access to the computer,a discussion document (glorified notes) (June 1998)
A complete access solution to the computer

ACCESS METHOD:

For total access a switch user requires:
access to switch based software
access to keyboard driven software
access to mouse driven software
and requires all the software to recognise the input from the switches.

Switch based software:
has switch access programmed in (the program itself monitors the status of the various registers)
either monitoring the
serial port,
the Keyboard buffer,
or mouse button flags.

1. Serial port switches:
responds to the program monitoring the signals from the serial port.
requires a switch switch box which plugs into the serial port (com1 or com2) on the computer.

2. Mouse driven software:
Operates through the software monitoring the status of the mouse buttons.
It operates contextually and positionally according to where the mouse pointer is positioned.
Switch access is via a mouse extension box (Semerc mouser etc).

3. Keyboard activated software:
responds to a selection of keyboard entries
ie. space and return to move through hyperlinks in Internet explorer.
Some switch written software has space/return programmed as set input keys. Switch access requires hardware to connect switches to the keyboard usually an additional hardware which connects between the computer and the Keyboard.

difficulties/advantages to each method:
1. Serial switch access:
Requires a hardware component.
Requires switch software that is written to read the serial port and respond appropriately
Will not work with standard mouse driven software unless additional programming.
There has been considerable difficulty with differring hardware serial ports on computers with modification to the hardware to allow it to work universally (this is now completed). Some computers have two serial ports some have one (some portables have none). The serial port on most computers is used for connectivitity with other devices (modems, networks).
Is limited to two seperate/direct switch inputs *??*

2. Mouse switch access
requires a hardware component.
requires switch software to monitor the mouse clicks.
Works with all standard mouse driven software.
Is limited to two seperate/direct switch inputs.

3. Keyboard switch access
Requires a hardware component
requires switch software to monitor the keyboard input.
Can work with all software since all input can be echoed by the keyboard.
Is unlimited in seperate/direct switch inputs and can use strings/macros.

solution 1
Using different hardware to allow complete access via switches you would need a switch serial box
a keyboard switch box
a mouse switch box
You then have to change the physical switch connection according to the program (ie plug/unplug according to whim/use, employing the well known technical operating technique of Repeat:plug/test/unplug/plug/test: until success)

solution 2
Use a single hardware box which has hardware connections to the keyboard. Keyboard connection can operate as the two mouse switches (easy via the keyboard) and it can operate as serial switches (I've no idea how easy it is via the keyboard).
It can work flexibly with keyboard inputs (space/return for Internet Explorer etc and other combined keystrokes (either prewired as in Don Jonson or programable as in Keyswitch+, and Intellikeys).
It can be used to input strings or any keyboard command sequence (macro)

ACCESS CONTROL:

switch access to software (Direct or Indirect)

Direct
access to switch software is usually progrmmed to be direct/scanning.
Scanning software:
Clicker/Windows switch/SAW/the other one.
using any or all of the above access methods.

Indirect access:
via mouse input
positional control of the mouse pointer required.
or Hypertext link type program (Clikit/hotspots/Windows switch/SAW/browser).

Access to the computer

Physical access:
Access to the keyboard
<diagram>

level of difficulty solution
1. mild software adaptions: sticky keys, keyboard repeat

2. moderate hardware adaptions: Keyguards, large/smaller keyboards.

3. severe alternative access: switch scanning to keyboard function

if you have additional sensory difficulties

add solution

visual impairment: auditory feedback
auditory impairment: visual feedback
cognitive impairment: try everything

Access to the computer wimp
most of our computer access is not through the keyboard but using a mouse pointer device.
so repeat scheme for mouse control
<diagram>

level of difficulty: solution
1. mild: software: slow mouse movement enhance click
2. moderate: hardware: roller ball, larger/smaller mice, joystick.
3. severe: switch access to control pointer via scanning grid

remember we are only considering physical difficulty
so add additional difficulties:and additional solution
visual impairment: auditory feedback (mouse position, mouse over)

auditory impairment: visual feedback (highlighting, large, flashing mouse pointer)

additional cognitive impairment: Real difficulty

Organising computers in school

layout/networking/classroom v. computer base

Information technology policy

-Simplified Policy document