GB2153568A - Input selection apparatus - Google Patents

Abstract

A keyboard for use by handicapped persons has an array of large keys (1 to 16). An overlay (19) is provided on which a printed pattern defines areas (20 to 23) covering two or more of the keys (1 to 16). Touching any key within one of the areas is determined by software (e.g. a microprocessor) as being a touch in that area. <IMAGE>

Description

SPECIFICATION Input selection apparatus The present invention relates to input selection apparatus, more particularly to input selection apparatus for use with an interactive display system and in particular to input selection apparatus capable of adaption to the needs of persons having different levels of physical and or mental handicap.

Training aids for use by the physically and mentally handicapped are often limited by the inability of such handicapped persons to interact with the training aids.

For example small computers may be programmed to play an interactive game with the handicapped and may provide a useful educational aid particularly for young handicapped persons.

However, most kinds of keyboard for providing inputs to computers provide an array of keys which may bewilder the mentally handicapped and which are too precise in their manual operating requirements for many of the Dhysically handicapped.

It is an object of the present invention to provide an input selection device which is readily adaptable to the needs of persons having differing mental and or physical handicaps.

According to the present invention there is provided an input selection apoaratus comprising a unit which has a plurality of input devices each of which is responsive to manual action thereon to cause a signal characterising itself to be transmitted to data processing means, in which the unit has a removeable overlay arranged to define a plurality of sections each of which overlies at least two adjacent input devices of said plurality of input devices and in which the data processing means is adapted to respond to a signal characterising any input device underlying one of said sections as a signal characterising that section.

Within the scope of the invention, the apparatus described above may be modified in that the overlay is such that some of the input devices do not have an overlying said section whereby added spacing is provided between at least some sections, the sections having the added spacing overlying possibly only one input device, and in that the data processing means is adapted to respond to a signal characterising any said input device not underlying a said section to ignore that signal.

Preferably each of the input devices is of the kind responsive to the presence of a touching object (e.g. a finger) to cause the signal characterising itself to be transmitted.

A plurality of interchangeable overlays may be provided each of which defines a differing arrangement of sections, said data processing means being adaptable to forward signals characterising sections in dependence upon the overlay fitted for the time being.

The processing means may be a suitably programmed microprocessor integral with the input selection apparatus and having a plurality of selectable programmes, the programme being selected in dependance upon the arrangement of the sections defined on the overlay fitted for the time being. The microprocessor may be arranged to cause a signal defining the section acted upon to be transmitted to further means responsive to such signals.

Each section of an overlay may be amrked with an alpha-numeric character or a symbol or colour such that by displaying such a character, symbol or colour on an associated display device interaction with the system may be encouraged.

Input selection apparatus in accordance with the invention will now be described by way of example only with reference to the accompanying drawing of which: Figure 1 is a three dimensional view of the apparatus with one of the overlays in place; Figure 2 is a plan view of the apparatus of Figure 1 showing several possible arrangements of sections on different overlays; Figure 3 is a block schematic diagram of the circuitry of the apparatus of Figure 1; Figure 4 is a block schematic diagram of an interactive display system utilising the apparatus of Figure 1, Figures 5 to 8 are flow charts showing programme operations in respect of different arrangements of sections on overlays fitted to the apparatus, and Figure 9 is a block schematic diagram of an alternative circuit arrangement to that shown in Figure 3.

Referring to Figures 1 and 2 the apparatus comprises sixteen 'touch-sensitive' keys 1-16 mounted in a surface 17 which is supported at an angle by a housing 18. Within the housing 18 circuits for detecting operation of any of the keys and for translating operation of such keys to give a preselectable data output are provided. The operation of these circuits is described hereinafter.

To facilitate operation of the keys 1-16 by slightly handicapped persons each key is approximately fifty millimetres wide by seventy-five millimetres in length. The keys are separated from each other by a distance of approximately twelve millimetres.

In use the apparatus is fitted with one of a number of interchangeable overlays 19 of, for example, a plastics material. Each of the overlays may carry markings defining an area which covers more than one of the keys and the overlay 19 shown provides the apparatus with four such sections 20-23.

Within each section on the overlay 19 different markings may be provided in dependance upon the use to which the apparatus is being put. Whilst as shown the markings are geometric shapes the markings may also be for example colours, alphanumeric characters, graphics symbols or pictures.

Various combinations of the keys 1-16 may be used in the sections of the overlay 19 to cater for differing ievels of handicap of an operator. In one case for severe handicap it is possible to use the apparatus as one large pushbutton providing a simple operated or non-operated response. Other possible arrangements are shown by chain-dot lines in Figure 2.

For example if two large keys are required the eight keys 1-4 and 9-12 as shown by the line 30 may be enclosed within a section marked on the overlay to provide one "key" whilst the other eight keys provide the second large "key".

In the case of the overlay 19 of Figure 1, the key 20 comprises the keys 1, 2, 9 and 10 and the keys 21-23 comprise logical combinations of four keys each as will be easily recognised. Eight vertical keys may be provided in the manner shown by the line 31 whilst eight horizontal keys could be provided in the manner suggested by the line 32. If four horizontal keys are required these may be provided in the manner suggested by the line 33.

In an alternative mode of use where greater spacing between sections is required alternate ones of the keys 1-16 may be indicated on the overlay 19 as indicated by the lines 34. In this mode of operation any touch on a non-designated key (e.g. the key 7) will be ignored.

Output signals from the apparatus to data-using equipment is by way of a ribbon-type cable 24.

Turning now to Figure 3 the touch sensitive keys 1-16 are of the capacitance type in which the presence of a touching object (e.g.) a finger (or in the case of larger keys, say, a hand) causes a variation in the capacitance.

A square wave clock signal is provided to each of the keys 1-16 from a clock generator 40. The frequency of the clock generator 40 is controlled by a frequency control circuit 41 to provide overall sensitivity control of the response of the touch sensitive keys 1 to 16. However it will be realised that the square wave clock signal and or frequency control could be provided by use of a microprocessor 42 which also receives the clock signals.

The clock signals are differentiated by the capacitance of the keys 1-16 each of which passes the signals by way of a respective local sensitivity control circuit 43 to an analogue detector 44 which provides either a binary "0" output if its associated key 1-16 is not operated (i.e. touched) or a binary '1' output in the operated state.

The detector circuit 44 is in practice a "monoflop" which is triggered if the amplitude of the square wave is sufficient. The respective local sensitivity controls 43 are adjusted such that when the associated keys 1-16, are not touched the amplitude of the pulses is just sufficient to trigger the respective analogue detectors 44.

The output of the detectors 44 is fed by way of "debounce" circuits 45 to a one out of sixteen addressable multiplexer 46 which is addressed by the microprocessor 42 and which gates the selected signal to an output 47. The microprocessor 42 forwards an appropriate data signal to outputs connected to the ribbon cable 24 which data indicates either that none of the keys 1-16 has been touched or which of the keys 1-16 or which section of the overlay 19 has been touched.

The microprocessor 42 may be set to operate in a number of modes. If for example the apparatus is required for use with all sixteen keys then the scanning pattern of Figure 6 to which reference is now made may be used.

When the microprocessor 42 enters this mode of operation each of the keys 1 to 16 is scanned in turn until one of the keys is found to be operated or until all of the keys have been scanned once. By setting to continuous scanning, the microprocessor 42 remains in a loop, scanning each key in turn, until a key is operated.

Once one of the keys is operated the microprocessor 42 returns to a main programme path which determines from the key address which of the keys 1-16 has been operated (touched) and the data to be sent.

In the case of testing individual keys of the apparatus the key address is preset by the microprocessor programme and the macro-function of Figure 5 is used. This returns to the main programme with either a true (operated) or false (unoperated) indication.

For keys grouped in sections under one of the overlays 19 the flow chart of Figure 7 is used. In this case a preselectable code to check for operation of a specific section is applied to a table to determine which of the keys 1-16 belong to the particular group. In combination with the single key test macro-function of Figure 5 a touch on one of the sections of an overlay 19 may be detected.

In another mode of operation (Figure 8), on return from the sixteen key test macro-function of Figure 6, the key address is translated to give a section definition for the overlay 19 in dependance upon the returned key address and preselected data determining the arrangement of sections in the overlay 19.

Referring now to Figure 4 in an example of the use to which the apparatus may be put the cable 24 is connected to a processor 50 of a typical interactive game computer 51 which is of the kind sometimes referred to as a home computer.

Such home computers comprise a keyboard 52, voice synthesis circuitry 53, a graphics generator 54 and a conversion circuit 55 which combines the graphics and voice signals to provide an output signal compatible with an ordinary domestic television set 56.

The keyboard 52 may be used to programme the processor 50 or, more usually, a preprogrammed cassette (not shown) is plugged in to the processor 50.

Once an appropriate overlay has been fitted to the apparatus of Figure 1 and its microprocessor given key grouping data in respect thereof the processor 50 may be caused to commence displaying information on the television set 56 accompanied by appropriate sound stimuli.

For example a pentagon may be displayed on the screen for comparison with the overlay markings accompanied by a voice synthesis question such as "which one is this?".

If the section 21 (of Figure 1) is touched the processor 50 will receive a corresponding indication on the cable 24 and may respond with a verbal cue such as "well done" and may proceed to display a further picture.

If one of the other sections 20, 22 or 23 is touched then the processor 50 may respond in an appropriate manner.

It will be realised that whilst herein the apparatus includes its own microprocessor decoding system, the processor 50 of the computer 51 could be arranged to control the scanning of the keys 1-16 with inclusion of appropriate programmes in the loading cassette and extension of the number of wires in the ribbon cable 24.

It will also be appreciated that data defining the section arrangement for any particular programme could be transferred to the microprocessor 42 from the processor 50 by way of the ribbon cable 24.

Referring now to Figure 9 in an alternative keyboard to that shown in Figure 3 an analogue multiplex 60 receives the output signals from the keys 1 to 16 and key scanning is effected by addressing on leads 61. Only a single sensitivity control 43 is needed together with a single analogue detector 44 which outputs to a single debounce circuit 45. The Clock 40 is set to run at fixed pulse rate of One Hundred and Twenty kilohertz.

The apparatus may be used in the same manner as the apparatus of Figure 3 but is less costly in production.

The apparatus may be impiemented using a double sided printed circuit board which may carry the keys and all of the components associated therewith.

It will be realised that in ,r-e simplest form the apparatuses of Figures 3 any 9 may be provided without a microprocessor, addressing of the respective multiplexers being carried out by the host computer processor 50. In such circumstances the host computer processor 50 may be programmed to include the scanning programmes of Figures 4 to 8.

Claims (8)

1. Input selection apparatus comprising a unit which has a plurality of input devices each of which is responsive to manual action thereon to cause a signal characterising itself to be transmitted to data processing means, in which the unit has a removeable overlay arranged to define a plurality of sections each of which overlies at least two adjacent in put devices of said plurality of input devices and in which the data processing means is adapted to respond to a signal characterising any input device underlying one of said sections as a signal characterising that section.

2. Apparatus as claimed in Claim 1, in which each of the input devices is of the kind responsive to the presence of a touching object (e.g. a finger) to cause the signal characterising itself to be transmitted.

3. Apparatus as claimed in Claim 1 or Claim 2, modified in that the overlay is such that some of the input devices do not have an overlying said section whereby added spacing is provided between at least some said sections, the sections having the added spacing overlying possibly only one input device, and in that the data processing means is adapted to respond to a signal characterising any said input device not underlying a said section to ignore that signal.

4. Apparatus as claimed in any one of Claims 1 to 3, in which the removeable overlay is one of a plurality of interchangeable overlays each of which defines a differing arrangement of sections, said data processing means being adaptable to respond to a signal characterising any input device underlying any of said sections as a signal characterising that section in dependence upon the overlay fitted for the time being.

5. Apparatus as claimed in Claim 4, in which the data processing means is a suitably programmed microprocessor integral with the input selection apparatus and having a plurality of selectable programmes, the programme being selected in dependence upon the arrangement of the sections defined on the overlay fitted for the time being.

6. Apparatus as claimed in Claim 5, in which the microprocessor is arranged to cause a signal defining the section acted upon to be transmitted to further means responsive to such signals.

7. Apparatus as claimed in any one of Claims 1 to 6 for use with an interactive display system, in which each section of the overlay, or each overlay as the case maybe, is marked with an alpha-numeric character or a symbol or colour such that by displaying such a character, symbol or colour on an associated display device interaction with the system may be encouraged.

8. Input selection apparatus substantially as herin before described with reference to the accompanying drawings.