Once pupils are familiar with the timed activation 'Popup' levels and can respond to on-screen program generated cues, they should begin to work with the targeting levels. These levels introduce the concept of both horizontal and vertical scanning and require the user to activate the switch when a moving object is within a specific area of the screen.
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The object moves either horizontally or vertically across the screen at a user selectable speed. The switch must be activated when the object is within the target area to trigger the animation sequence. Any activation of the switch outside of this area is ignored. |
SENSwitcher presents two levels of ten activities each. In the first level shapes and simple objects are used with a clearly defined target area. In the second, scenes are used and the user is required to activate the switch when objects are aligned in either a horizontal or vertical plane.
| Pupils will activate
a switch in response to a specific program generated event. |
Which is broken down into four smaller steps.
| 17 |
Pupils
can track a moving object
horizontally across the screen, activating the switch when the object
is close to the target area. |
| 18 |
Pupils
can track a moving object horizontally across the screen, activating
the switch when the object is within the target area. |
| 19 |
Pupils can track a moving object vertically up or down the screen, activating the switch when the object is close to the target area. |
| 20 |
Pupils can track a moving object vertically up or down the screen, activating the switch when the object is within the target area. |
| CASE STUDY EIGHT- TARGETING Dominic understands cause and effect, switch building and can activate a switch in response to both visual and auditory cues from the computer. He is working towards using a scanning system in an attempt to meet his future communication needs. Early attempts to introduce switch scanning were not successful as Dominic had some difficulty in tracking a traditional scanning highlight (the box around the object) across the screen. Dominic is using the targeting level of SENSwitcher as an aid to understanding the relationship between the moving object and the target cell. He is making good progress and can track and correctly target slow moving objects moving horizontally left to right across the screen. |
One could argue that the overall aim of learning to use switches is to enable choice. For some people that will mean choosing to make something happen or not, for others, especially those for whom assistive technology may be their primary means of extending influence and control over their environment, it may mean using a switch to select from a range of options such as symbols on a communication device.
SENSwitcher scanning level provides eight activities designed to promote the development of row scanning skills. Row scanning works by sequentially highlighting a number of objects or cells presented in a horizontal row across the screen. Each object is highlighted (gains focus) in turn as the scan moves across the row. The user selects an object or cell from the row by activating the input device when the object gains focus.
For example:
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The scan moves across the row sequentially from left to right, highlighting each cell as it gains focus. The user activates the switch when the cell he wishes to select is highlighted. |
Further information about scanning systems can be found in the Priory Woods Assistive Technology Skills Progression document, which can be downloaded from the Northern Grid web site.
In the first six activities, choices are made between two objects using the row scanning principle. Teachers can choose to use either shapes or objects and can select the speed of the scan to suit the individual child. The final two activities use scanning proper by introducing empty cells into the row, first a single empty cell (wait, press) followed by two empty cells (wait, wait, press).
| Pupils
will activate a switch to select a specific object using row scanning. |
This is broken down into four smaller teaching steps:
| 21 |
Pupils
can activate a switch to select ANY of
two on-screen objects using the row-scanning principle. |
| 22 |
Pupils
can activate a switch to select a specific animation from two on-screen
objects using the row-scanning principle. |
| 23 |
Pupils can differentiate between an empty and filled cell, activating the switch to select the filled cell using the row-scanning principle. |
| 24 |
Pupils can differentiate between two empty and a filled cell, activating the switch to select the filled cell using the row-scanning principle. |
| CASE STUDY NINE - ROW SCANNING Andrew is a proficient switch user and is able to sequence events and respond to program generated cues. He was introduced to SENSwitcher scanning levels as part of a structured programme to help him develop scanning skills to enable the use of an augmentative or alternative communication (AAC) device. Andrew started to use scanning to choose between two objects, first on his own and then in response to a question from the teacher, "Can you find the frog?" Andrew learned to do this and was moved onto empty cell scanning which he quickly internalised. Andrew's teacher has now created a series of linked communication grids using Clicker 4, covering different vocabulary areas. Vocabulary and navigational cells are row scanned, enabling Andrew to select the appropriate grid to initiate or respond to communicative opportunities. |
| ©
2001 Northern Grid for Learning |