GB2303707A - A joystick control adapter - Google Patents

Abstract

A control adaptor 10 intended for use by the occupant of a wheelchair to control a computer comprises a housing designed to fit over an existing joystick in the chair arm 20, the joystick normally being used to control the chair but temporarily inactivated. The housing has four magnetic field sensors 190, e.g Hall effect devices, secured at equally spaced positions on its interior and influenced by a ring magnet 170 which is placed on the joystick shaft 180 after removal of knob 160. Replacement of the knob holds the magnet in place beneath the upper portion of the housing. The device described is provided with input/output connectors and is preferably designed for wireless communication with a receiver (80, Fig. 1) connected to the computer.

Description

A CONTROL ADAPTOR This invention relates to a control adaptor, and more particularly to a remote control adaptor suitable for use by wheelchair bound sufferers of Cerebral Palsy or other disabilities.

Sufferers of Cerebral Palsy and other debilitating disabilities can exhibit very poor motor control. These motor disfunctions unfortunately provide a natural barrier to a number of tasks taken for granted by the able-bodied population. In the majority of cases, Cerebral Palsy sufferers and other seriously disabled persons are confined to wheelchairs.

A disabled person's wheelchair is invaluable as it allows that person to get around and enjoy some of the activities undertaken by the able-bodied population.

In recent times, wheelchairs have been electrified so as to award disabled persons a degree of autonomy.

These electric wheelchairs typically comprise a conventional wheelchair to which a rechargeable battery pack and a motor control unit are fitted. Typically, the motor control unit comprises a box built in to the arm of the wheelchair that enables the user to move the chair in any given direction. Movement of the wheelchair is usually accomplished by way of a joystick mounted in the arm of the chair. In this way, a user can manipulate the joystick and thereby move the chair.

Fortunately, wheelchair bound disabled persons have sufficient motor capabilities to enable the use of a joystick for motor control. It is those people to whom the present invention will prove to be the most useful.

Over the last few years, the use of computers both in the home and at work has grown almost exponentially. It is not unsurprising therefore that disabled persons have greeted this computerisation process with great enthusiasm given that computerisation enables the completion of tasks that may otherwise have been beyond the capabilities of a disabled person.

Until relatively recently, almost all computers ran a command based disk operating system or DOS. However, with the advent of graphical user interfaces (GUl's) such as Windows (a trade mark of the Microsoft Corporation) more and more of the DOS based computers are being converted to a mouse operated Windows environment. GUI's offer a vastly simplified command structure over conventional DOS systems.

GUI's such as Windows are typically driven by a mouse, movement of which causes corresponding movement of a pointer on the computer monitor. The mice are usually provided with a minimum of two buttons and multiple clicks of these buttons enable the performance of specific tasks within the GUI. Furthermore, objects displayed on the computer screen can be moved around by depressing and holding one of the mouse buttons during movement.

Disabled persons are effectively incapable of using a keyboard due to the fact that their motor control is so limited that the striking of a particular key is almost impossible. In consequence to this, it was hoped that a mouse operated system using a GUI would enable all but the most severely disabled persons to operate a computer.

However, it has been found that the use of conventional mice is fraught with difficulties for a disabled person. In particular, disabled persons with poor motor control often have severe hand tremors. When such a person attempts to use a GUI such as Windows, control of the cursor upon the screen becomes problematic to such a degree that the use of the GUI is prohibited. Numerous different designs of mouse have been adopted in an effort to overcome this problem. In addition, other devices such as tracker balls have also been proposed to facilitate movement of the pointer on the screen.

Whilst tracker balls are easier to use than mice, they still suffer from a significant disadvantage in that any movement of the pointer on the screen requires an unduly large movement of the operator's hand. For disabled persons with poor motor control, such a large degree of hand movement is often very tiring and uncomfortable. Furthermore, mice and tracker balls are designed to be operated on a desk or work station surface. Disabled persons in wheelchairs often encounter difficulties when trying to use these pointing devices on a desk surface.

In view of the above mentioned problems, there exists a need in the art for a pointing device that is easily moveable by a severely disabled person without causing undue vibration of a pointer on the monitor. It would also be helpful if that device were to be mounted in close proximity to the wheelchair bound disabled person.

The present invention overcomes the above mentioned problems by providing a device that enables existing users of electric wheelchairs having a joystick to utilise the full capabilities of a GUI computer.

In accordance with the present invention, therefore, there is provided a control adaptor comprising four magnetic field sensing devices arranged to sense changes in magnetic field due to movement of a magnetic object.

Preferably, the adaptor is provided with an aperture within said adaptor, said magnetic field sensing means being provided on the perimeter of said aperture. In one embodiment, the aperture is substantially circular.

It is also preferred that said magnetic field sensing devices are arranged in a cross shape "+", and said magnetic object is free to move within said aperture.

Preferably,the aperture is sized so as to accept a joystick shaft therewithin whilst allowing full movement of said shaft.

It is also preferred that said magnetic object is removably securable on said shaft such that movement of said shaft causes corresponding movement of said magnetic object. In which case, the joystick may further comprise a removable knob capable of being mounted on said shaft, thereby securing said magnetic object.

In one embodiment, the joystick is mounted on a powered wheelchair such that said joystick controls movement of said wheelchair.

In all of the embodiments, it is preferred that the adaptor includes wireless transmission means for wireless communication with a receiver, the receiver being connected to a computer such that movement of said magnetic object causes movement of a pointer on a computer monitor.

It is preferred that the magnetic object is a ring magnet, and that the magnetic field sensing devices comprise Hall Effect Devices.

The adaptor may have at least one button mounted thereon, and may have at least one output socket for wired communication with an external device.

In addition, it is preferred that either the wheelchair arm or the adaptor incorporates a master switch which would switch off the powered wheelchair and thereby prevent unwanted movement of the chair when the adaptor is being used.

Preferred embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, throughout which like parts are referred to by like references, and in which; Figure 1 shows a schematic perspective view of a wheelchair arm fitted with a control adaptor according to the present invention, the adaptor being in wireless communication with a receiver connected to a host computer;Figure 2 shows a schematic perspective view of a desktop 'dummy' module capable of receiving the remote control adaptor according to the present invention and communicating with a receiver and host computer similar to that pictured in Figure 1; Figure 3 shows a sectional view along the line A--A of Figure 1; Figure 4 shows a schematic plan view of the wheelchair arm and partly disassembled control adaptor placed thereon; and Figure 5 schematically illustrates a set of electronic components provided to enable operation of the control adaptor according to the present invention.

With reference to Figure 1, a control adaptor is shown, the adaptor 10 having been fitted over a motion control module which forms an arm 20 of a wheelchair (not shown). The control adaptor 10 comprises an approximately planar body 30 having a pair of side arms 40 depending perpendicularly and in parallel therefrom. The planar body 30 includes a circular aperture 50 in a forward portion thereof. A rear portion of the planar body 30 is provided with a series of input/output (VO) connectors 60 for communication with external devices such as switches. The wheelchair arm 20, in common with traditional devices, is provided with a joystick 70 extending vertically from a top surface thereof.

The control adaptor 10 is placed in use over the arm 20 of the wheelchair such that the joystick 70 extends though the aperture 50 in the adaptor 10. Preferably, the adaptor 10 is releasably secured to the arm 20 in order to prevent accidental mislocation of the device. Furthermore, the adaptor 10 preferably engages with means (not shown) on the wheelchair arm 20 such that the joystick 70 extends through a centre point of the circular aperture 50.

The control adaptor 10 is preferably capable of wireless communication with a receiver 80. The receiver 80 is in turn connected to a host computer via conventional VO devices.

With reference to Figure 2, a second embodiment of the present invention is shown. The controller adaptor 10 is identical to the unit depicted in Figure 1 and is capable of being mounted over a desktop 'dummy' module 90. The desktop 'dummy' module 90 is designed to enable a handicapped person to use their computer at times when they are not seated in their wheelchair. The module 90 may be fitted to a table or an arm of an armchair, for example. In this way, a disabled person may still enjoy the benefits of the present invention whilst not being restricted to using their computer only at times when they are seated in their wheelchair.

The module 90 comprises a box 100 which may have a bevelled rear face 110 to improve the comfort of the device in use. A top surface 120 of the module 90 has a circular aperture 130 provided therein. A dummy joystick 140, mechanically similar to that depicted in Figure 1, is provided in vertical extension from the aperture 130 in the module 90. Preferably, the top surface 120 of the module 90 is provided with raised portions 150 so as to restrict the movement of the adaptor 10 when placed over the module 90.

Within the module 90 there is provided a simple mechanical arrangement which enables the joystick 140 to operate in a conventional manner. The control adaptor 10, when placed over the module 90, operates in a manner identical to that shown in Figure 1 and is capable of wireless communication with the receiver 80.

This second embodiment enables a disabled person to utilise the control adaptor 10 according to the present invention at all times, whether they are seated in their wheelchair or not. In both of these embodiments, the planar body 30 of the controlled adaptor 10 may be provided with a number of buttons or other control switches (not shown).

Alternatively, or in addition, other control devices such as head and feet switches may be connected to the control adaptor 10 by way of the IIO sockets 60.

These buttons or control switches may have specific functions or, more preferably, may have custom functions selected from a computer program, for example. The joysticks 70 and 140 used in connection with the present invention have, in common with the majority of conventional devices, a removable head portion 160 which may be removed by any person, for the purpose of fitting magnetic means 170 thereon, thereby to render the joystick 70 or 140 capable of operation with the device according to the present invention.

Figure 3 illustrates the operating principals of the present invention by showing a cross-sectional view along the line A--A of Figure 1.

With reference to Figure 3, the control adaptor 10 is shown in section and fitted over the arm of the wheelchair and its joystick 70. The joystick 70 is shown with its head portion 160 removed. However, in use, the removable head portion 160 would be secured to the joystick 70. The joystick 70 is capable of movement in a plane defined by the size of the aperture 50 in the adaptor 10.

Prior to use, the head portion 160 of the joystick 70 is removed and said magnetic means 170 is fitted over a shaft 180 of the joystick 70. The magnetic means 170 is sized so as to fit snugly over the shaft 180 and to exhibit a minimal amount of movement when the removable head portion 160 is secured to the joystick 70.

Within the control adaptor 10 there are provided four Hall Effect devices 190, two of the devices being provided on the joystick's x-axis and two being provided on the joystick's y-axis. Figure 3 shows only the x-axis devices, the y-axis devices being hidden from view. As shown in Figure 3, each pair of devices is positioned within the adaptor 10 such that each device is on a directly opposite side of the joystick 70 and provided substantially equidistant therefrom.

The adaptor 10 is shown in Figure 3 as being fitted over the arm 20 of the wheelchair, but a similar arrangement would be obtained if the control adaptor 10 were to be fitted over the 'dummy' module 90.

The magnetic means 170 is preferably a ring magnet having a substantially annular shape and a substantially constant north/south axially polarised field. It will be immediately apparent that other arrangements of suitable magnetic devices may be employed to achieve the same effect. For example, a pair of north/south polarised bar magnets may be encapsulated in resin so as to form an approximately annular shape and then provided over the shaft 180 of the joystick 70 in a manner identical to that described above.

Figure 4 illustrates a plan view from above the substantially planar body 30 of the control adaptor 10. In Figure 4, the control adaptor 10 has been partly disassembled to better illustrate the working components of the present invention. As discussed above, the control adaptor 10 is provided with four Hall effect devices 190, two in the x-axis of the joystick 70 and two in the y-axis of the joystick 70. The Hall effect devices 190 are shown connected to a printed circuit board (PCB) 200, the PCB having a plurality of electronic components mounted thereon. The PCB 200 controls the operation of the adaptor 10 and is capable of communication with external devices via the VO sockets 60, or wireless communication with the receiver 80 by way of transmission means 210.

Preferably, the transmission means 210 comprises an infra-red diode, the receiver 80 being adapted to sense and receive infra-red signals. However, it will be immediately apparent that other transmission arrangements may be adopted.

The adaptor 10 is shown as being fitted over the wheelchair arm 20 and the joystick 70 extends vertically and perpendicularly from the arm 20 through the circular aperture 50. As shown, the head portion 160 has been removed from the joystick 70 and the magnetic means 170 is shown as having been placed over the shaft 180 of the joystick 70.

Figure 5 illustrates schematically the various electronic components that may be applied to the printed circuit board 200. The control adaptor 10 is preferably provided with a battery power source 220 in order to preserve the wireless and portable nature of the adaptor 10. Various different kinds of battery may be utilised, but preferably, the battery is a rechargeable nickel cadmium battery. In the preferred embodiment, the battery 220 is connected to a battery supervisor 230 which is in turn connected to a microcontroller which oversees the operation of the adaptor 10. In this way, the battery supervisor 230, in conjunction with the microcontroller 240, may warn the user of the adaptor 10 of low battery power by way of an indicator 250. The battery supervisor 230 also oversees the distribution of power from the battery 220 to the various circuit components.

In use, the Hall Effect detectors 190 detect changes in magnetic field due to movement of the magnetic means 170 which is fixed to the joystick 70. These changes in magnetic field cause the Hall Effect detectors 190 to produce signals.

Those signals are then passed to signal amplification and conditioning means 260.

The signal amplification and conditioning means 260 may purcly comprise an amplifier for amplifying the signals. However, the signal amplification and conditioning means 260 may additionally comprise complex filter devices to remove any small unwanted variation in the signals from the Hall effect detectors 190, the variations perhaps being caused by unconscious hand tremors of the operator. In this way, the pointer on the computer screen will be relatively free from flicker thereby aiding use of the adaptor by a disabled person. Alternatively, rather than providing actual filter components on the PCB 200, the signal filtering process may be carried out by suitable software filters run on the host computer. Specialist software functions may also be initiated by button or switch depressions.

The amplified and filtered signals are then passed to an analogue to digital convertor 270 which in turn passes the digital signals to the microcontroller 240. The microcontroller 240 converts the amplified and conditioned digital signals from the A/D convertor 270 from signals that describe the changes in magnetic field into signals that describe the movement of the joystick 70 that must have occured to produce the aforementioncd changes in magnetic field. In other words, the microcontroller 240 converts the signals from the Hall Effect detectors 190 into a series of signals that describe the movement of the joystick 70 in an X-Y axis. These X-Y movement signals are then passed from the microcontroller 240 to a signal modulator 280 prior to their transmission by the transmission means 210.

The microcontroller 240 is also connected to the VO socket 60 and any other switches (generally designated 290) provided on the control adaptors exterior by way of a data buffer 300. The microcontroller 240 is also connected to an address switch 310 which allocates addresses within the PCB 200.

As mentioned above, the battery supervisor 230 oversees the provision of power to a plurality of circuit components. In this case, the battery supervisor 230 powers the Hall Effect Devices 190, the signal amplification and conditioning means 260, the A-D convertor 270, the microcontroller 240, the signal modulator 280 and the transmitter means 210.

In addition, it is preferred that the control adaptor incorporates an on/off switch which may or may not be linked to the on/off switch for the wheelchair. For example, the adaptor on/off switch may be arranged in such a fashion that the adaptor may not be operated until the motor function of the wheelchair has been disabled by way of the wheelchair on/off switch. At this point, it should also be noted that the 'dummy' module 90 need not be provided with any sort of power source.

It will be apparent that a variety of different circuit components may be incorporated onto the PCB 200. In this connection, it should be remembered that the above description relates only to a preferred embodiment and that other modifications may be made within the scope of the appended claims.

With regard to the forgoing, there has been described a control adaptor which may be fitted either on an arm of a wheelchair or additionally on a 'dummy' module.

The disabled person using the wheelchair is then easily able to use a computer without having to perform any movement other than the movements that they would normally perform when operating their wheelchair. In addition, the 'dummy' module enables computers to be operated at times when the disabled person is not seated in their wheelchair.

It is also conceivable that the control adaptor according to the present invention may be capable of operating other household appliances. For example, an automatic door switch could easily be manufactured so that key depressions on the control adaptor according to the present invention cause internal and external doors to open or close. Furthermore, it is not inconceivable that the control adaptor according to the present invention could be utilised to operate other household items such as cookers, washing machines and the like which have been suitably adapted to enable computer generated menu-driven control.

It will be understood, of course, that the present invention has been described above by way of example only and that modifications may thus be made within the scope of the appended claims.

Claims (15)

1. A control adaptor comprising four magnetic field sensing devices arranged to sense changes in magnetic field due to movement of a magnetic object.

2. The adaptor according to Claim 1, further comprising an aperture within said adaptor, said magnetic field sensing means being provided on the perimeter of said aperture.

3. The adaptor according to Claim 2, wherein said magnetic field sensing devices are arranged in a cross shape "+", and said magnetic object is free to move within said aperture.

4. The adaptor according to Claim 2 or Claim 3, wherein said aperture is sized so as to accept a joystick shaft therewithin whilst allowing full movement of said shaft.

5. The adaptor according to Claim 4, wherein said magnetic object is removably securable on said shaft such that movement of said shaft causes corresponding movement of said magnetic object.

6. The adaptor according to Claim 5 wherein said joystick further comprise a removable knob capable of being mounted on said shaft, thereby securing said magnetic object.

7. The adaptor according to any one of Claims 4 to 6, wherein said joystick is mounted on a powered wheelchair such that said joystick controls movement of said wheelchair.

8. The adaptor according to any preceding Claim, further comprising wireless transmission means for wireless communication with a receiver, the receiver being connected to a computer such that movement of said magnetic object causes movement of a pointer on a computer monitor.

9. The adaptor according to any preceding Claim, wherein said magnetic object is a ring magnet.

10. The adaptor according to any preceding Claim, wherein said magnetic field sensing devices comprise Hall Effect Devices.

11. The adaptor according to any preceding Claim, further comprising at least one button mounted thereon.

12. The adaptor according to any preceding Claim, further comprising at least one output socket for wired communication with an external device.

13. The adaptor according to any one of Claims 2 to 12, wherein said aperture is substantially circular.

14. A control adaptor substantially as hereinbefore described and as shown in the accompanying drawings.

15. A wheelchair having an adaptor according to any preceding claim mounted on an arm thereof.