Inside

Editorial...................................................................1

News: Liz Nade.......................................................1

Main Story: Powered Mobility – controls 2.............2

Article: Accessible Digital Camera.......................5

Volume 18 Issue 3 May 2009

TechnoTalkThe TASC Newsletter

We welcome any feedback, good or bad, that you may have on our service. Please feel free to contact us by phone on 02 9975 8469,email tasc@tscnsw.org.au or by writing to The Spastic Centre PO Box 184 Brookvale NSW 2100

TechnoTalk Newsletter is free and available from www.thespasticcentre.com.au/news/technotalk/

Editorial News...Welcome to my first editorial for TechnoTalk. For the next 12 months I will be acting as Team Leader for the TASC Consultants whilst Jo Ford is on secondment managing The Spastic Centre’s rural teams. Many of you will know me already as one of the occupational therapists at TASC. I look forward to bringing you some interesting news from the team over the next year in TechnoTalk.

This month Elizabeth Nade, occupational therapist, introduces herself to you. Liz started with TASC in March in a split position working across both technology and seating – this is a first for TASC and we are very happy to have Liz join the team in this exciting new role.

Natalie Carden, seating consultant continues her article from our last edition on control systems for powered mobility. This month Natalie is covering non-proportional control systems that can allow clients with limited upper limb function who can’t control a standard joystick to experience independent mobility.

Liz and I also have briefly described one option for people with a disability to access a digital camera from Technical Solutions. It is great there are options out there for people to get involved in photography as a leisure pursuit.

Happy reading,

Liza MacLean

Hi I’m Liz Nade; I’m an Occupational Therapist, new to the TASC team. I will be undertaking a split role between seating and technology, which I am really excited about. I have been working at The Spastic Centre for 12 months, and was in the adult team prior to coming to TASC.

I graduated as an OT in 2003 and have worked with people with chronic and acute mental illness and also worked in orthopaedic rehabilitation.

I really enjoy the challenge that comes from working with clients with complex seating and technology needs. I look forward to working with you in meeting your seating and technology goals.

POWERED MOBILITY – alternate controls explained, Part IIby Natalie Carden, Occupational Therapist, TASC Seating Consultant

In the last edition of TechnoTalk, we covered proportional control; that is, direct access to control the direction and speed of the powered wheelchair. The control devices presented were for use with the hand, finger, head, chin or foot. For many potential wheelchair users, the fine motor control of a proportional control system may not be possible. In this case, non-proportional control devices may be more suitable.

In this issue we will cover the many non-proportional control systems and devices that can turn potential mobility into reality.

Introduction

Non-proportional control provides access to self-initiated movement where proportional control is not an option. It allows the wheelchair user to move the wheelchair using a switch or several switches located anywhere that can be accessed consistently. Non-proportional control is indirect, that is, each switch provides a set direction and a set speed.

Non-proportional systems can provide access to wheelchair motion and also to other functions, such as tilt-in-space, recline, leg raise or horn, through the operation of a switch or several switches.

Before discussing devices, it is important to cover switches to ensure that the methods of activation of the more complex devices will be understood. The switches used with the non-proportional control systems can be either mechanical or electronic. Explanations of some of the many switches available are discussed below in the two categories:

1. Mechanical switches

Mechanical switches require the user to depress or displace all or part of the unit to activate. There are many types and sizes, requiring differing amounts of force. They are cheaper than electronic switches and can be placed just about anywhere.

Common types of mechanical switches are the Buddy Button, Specs, Leaf, Wand, Pillow, Tilt, Grip, Wobble, Rocker.

In addition to the single switches, there are several multi switch units, such as those pictured below with five switches in a single unit. When used with a powered wheelchair there would be a switch for forward, reverse, left, right and mode/on/off. Examples are: the Star switch, Wafer Board, Penta switch and joystick switches.

Main Story:

Star switch Water Board Penta switch Joystick switches

2. Electronic switches

Electronic switches differ from mechanical switches in that they require a power source for operation and the need to depress a switch is eliminated. No force or contact is required to activate, just motion across a field, beam or sensor. Some options to choose from are proximity, fibre optic and infrared switches.

• Proximity switches require a body part to enter the field of the switch. The range or field and speed are adjustable. Proximity switches can be placed in any position required. Some examples are near the jaw/chin, in a tray top or a head array. They will operate through most materials, depending upon thickness. www.asl-inc.com/Catalog/Index.asp?use=226

• Fibre optic switches. Thin transparent fibres (plastic) emit an invisible beam of light (works through internal reflection, ref: Wikipedia) that can be positioned to be broken by a body part for switch activation. A fibre optic switch would be suitable to operate a single switch scanning system, which will be covered below. Common locations for a fibre optic switch could be the chin/jaw area and the tray top. An example of use: several holes would be cut into a tray top with beams directed up through each. The user would move a finger across the hole corresponding to the direction of choice to move the wheelchair. Direction and speed are set, but programmable.

• Infrared switches involve “…frequencies beyond the red end of the visible spectrum, i.e. frequencies with longer wavelengths than red light. Perceived by humans as heat. Commonly used for remote-control devices…” (ref: Wikipedia).

• An example of an infrared switch is the Self-Calibrating Auditory Tone Infrared (SCATIR) switch. It “…works by detecting a beam of reflected pulsed infrared light. The Switch is a momentary- contact optical switch with auditory feedback. It is suitable for use with a variety of control gestures, such as eye-blink, eyebrow movement, finger movement, head movement, and facial muscle movement. It can be activated at a distance so the controlling body part does not need to be in physical contact with the switch sensor.” www.spectronicsinoz.com/product/scatir-switch

• Infrared switches are similar to the fibre optic switches in that they are most commonly used with single switch scanning systems. Both would be placed according to individual requirements in similar places and require movement in or out of a field to activate. Speed and direction are set, but programmable.

Non-proportional Devices

Head arrayThe ASL head array is one type of head array. It consists of a three-piece head support with a proximity switch embedded in each pad. The three switches provide forward, left and right with some veer possible when activating two pads simultaneously. Reverse can be added to the system using a sequence of taps to change forward to reverse. Alternately, reverse can be added using a separate switch.

www.asl-inc.com/Catalog/Index.asp?use=226

Scanning systems

Scan systems allow the user to operate wheelchair and seat functions with a single switch. To operate the wheelchair, the user would watch the visual display unit located in front of them as a set of direction arrows light up in sequence. When the direction of choice is lit, the user would activate the switch to select. Pressure on the switch must be maintained to continue moving, as momentary* (not latching*) switches are used for safety reasons. www.asl-inc.com/Catalog/Indexd978.html?use=226

The location and type of switch is chosen to best suit individual function. The switch can be mechanical or electronic. Scan systems are available through ASL, Penny & Giles and Dynamic. Current technology can incorporate a scan system into the master control unit of the wheelchair, e.g. G91s by Dynamic, as pictured. www.dynamiccontrols.com/index.cfm/1,92,html

Scan systems can be cumbersome to use and, therefore, are mostly used when an individual has only one reliable switch site available and good scanning skills.

The ClicktoGo is an example of a scanning device for switch operation of multiple systems.

“The ClickToGo is operated by single or multiple switches via a scanning interface. The eight direction indicators are illuminated by ultra-bright LEDs and can be scanned in many different ways. When a direction is chosen, pressing a switch drives the chair.”

• Integrating Communication, Environmental Control and Computer Access by Unique Perspectives Ltd” www.spectronicsinoz.com/browse.asp?cat=16969

Heavy Duty Joystick

The heavy duty joystick is an example of a multi switch unit. The website states, “It has eight driving directions allowing selection of forward, reverse, left, right and the four diagonal directions. Although a switched device, the Heavy Duty Joystick gives good performance when used with the correct acceleration and deceleration settings”. www.dynamiccontrols.com/index.cfm/1,92,html

As the name implies, the Heavy Duty joystick is an alternative for users who are hard on their joysticks and may otherwise damage the electronics inside a standard proportional joystick.

Sip and PuffSip and puff is pneumatic (mechanical) switch control. It is operated by intra oral air pressure, not respiration (Lange, 2005) and so can be used whilst using a ventilator. Four commands are used: hard puff, soft puff, hard sip, soft sip. The forward command is latched such that the wheelchair continues moving until a further command is received to stop or change direction. An emergency stop switch is built-in to stop the system should the mouth piece fall out of the user’s mouth. A fibre optic switch can be used.

Some versions have full directional control through the pneumatic switch commands. Others such as the ASL sip and puff system have a combination of intra oral control and head steering/veering. Further mechanical or electronic switches can be added to increase options as needed.

The Spastic Centre

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PO Box 184 Brookvale NSW 2100

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F: 02 9479 7233

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www.thespasticcentre.com.au

Switch Accessible Digital Camera

Technical Solutions have developed an interface to be used with some Pentax digital cameras (check supplier website for compatible cameras) to allow users with a disability to access the camera functions via one or two switches. This can allow users previously unable to participate in photography to have the ability to take pictures and use the zoom function. The camera can also be mounted to a user’s wheelchair with a Universal switch mount with camera bracket to allow the user to have independent access to their camera in a variety of environments.

With one switch, the user can activate zoom functions by holding the switch down and the interface will step through three zoom settings and then release the switch on the desired setting. A photo can then be taken by a short switch press.

With two switches, the user uses one switch to step through the zoom functions and the other switch to take the photo.

Switches could be positioned on a wheelchair tray, armrest or headrest for the user to access.

The Remote Switch Interface can be purchased separately or bundled with one of 3 Pentax camera options. This product was judged at the 2008 Australian Rehabilitation and Assistive

Technology Association Conference and awarded second prize in the “Better Technology Awards”.

For more information and pricing, see Technical Solutions www.tecsol.com.auor phone: 03 9737 9000.

ConclusionThis concludes our look at non-proportional controls. There are a considerable number of options to consider, so ensure a thorough evaluation is conducted by an occupational therapist or physiotherapist to determine which device or method will best suit the client’s needs.

Non-proportional systems open avenues of opportunity for people who cannot use the standard joystick. People who previously would have remained dependent can experience self-initiated mobility and the sense of freedom and achievement that comes with it.References: Lange, M. (2005). Power wheelchair access: Assessment and alternative access methods. Paper presented at 21st International Seating Symposium.

Liz Nade and Liza MacLean, Occupational Therapists

Camera mount

Remote Switch Interface with switch and camera