Overview & Purpose

This module provides an overview of the different types of switches and interfaces that can be used by students with disabilities. The module includes information on characteristics of switches and switch interfaces, mounting systems and suggestions for classroom switch activities.

Purpose of Switch Use

Switches offer access to anything electronic for persons with disabilities. They are a great way to begin experiencing independent control. Through a variety of interfaces, switches are connected to electronic devices. They work to turn things on and off or indicate choices when used with scanning software or interfaces.

For children with physical disabilities, a single, reliable movement can cause a toy to move or turn a radio on. Those with sensory impairments learn that they can be the controlling source of sound, light and vibration. Children with cognitive impairments are able to interact with toys and computers with a single "button," limiting the need for more complex directions. Switches provide new opportunities to learn and participate.

For example, a simple battery interface can
assist a student in creating a 'Spin Art' picture
with friends.

Children often begin by using switches with toys. This develops skills that can include:

• Turning them on and off,
• Moving them for social and communicative purposes, and
• Making choices to indicate preferences.

These skills provide a foundation for learning and for more complex technology use such as multiple switch use, computer interactions and more extensive environmental control.

Types of Switch Use

Environmental Control of appliances such as radios, fans, blenders, and televisions found in homes and schools.

Play & Exploration are expanded through using switches to independently participate in games and other recreation activities. Battery-operated toys or games such as Light Brite and Spin Art can be easily adapted for switch use.

Movement can be experienced with motorized mobility items such as powered wheelchairs and motorized cars (Jeeps, Big Foot cars) that are driven with single and multiple switches.

Computer Access is achieved through single and multiple switch access. Switches can be used in combination with other input devices such as head pointers and voice dictation software. A single switch user can use scanning systems, giving full access to any commercial software program. (For more information, see our module on switch and scanning systems.)

Communication is encouraged through early switch use. Single switch devices with recorded messages provide a way to relate language to the activity at hand and to initiate and participate in a variety of activities. More complex systems use multiple switches or internal scanning methods to access multi-layered designs.

Selecting a Switch

If a student is having difficulty participating and interacting with objects in the environment, you may decide to try a switch activity with him. Before you begin you need to observe him in his natural environment to determine his best "switch site"-- the body part and movement that he is most consistently able to control. It can be large or small, weak or strong. The movement should be reliable, meaning it can be repeated. A reflexive pattern is not a good choice. Since switches are designed to work with any body part, look for the movement that requires the least expenditure of energy and the one the student prefers. Ask an Occupational Therapist to help.

You may find more than one switch or switch site that can be used during the day as the student's position, energy level and activities change. All of these will affect the selection of the switch and where it is placed. The student should be able to initiate a movement to activate a switch and then be able to sustain and/or release contact with the switch. You can consider additional interfaces to ensure success.

Try a switch activity. Identify an electronic activity that is fun and motivating to the student. [Ablenet (Making Connections, 2001) suggests starting with a musical activity because of its popularity with students.] Select a switch with features that match the abilities of a student. Connect a switch to the music device (i.e. tape recorder). If the student is able to use his fingers, hands or fists, start with these as their interaction with a switch. The resulting response will all be within a contained visual field. Give the student lots of time to practice, encouraging him with cues and praise.

Types

Switches come in all shapes and sizes. The Abledata database (2001) reports the availability of almost 1800 switches! Switches are often activated by the hand or arm, but can be used with any body part. To independently use a switch, a student must be able to voluntarily move any single body part with large or small movements.

There are several categories of switch types. We have grouped them by how a switch is activated. See our handout on switch types for photos and further explanation.

• Push (or touch) switches are the most common type. The student activates the switch by pushing against its surface. These switches have a single surface area for activation.
• Lever switches can be activated by pushing in more than one direction. They are easily mounted.
• Motoric-Specific Movements activate other switches such as pinch, grip, bat, pull, etc.
• Activity switches require the student to complete an activity like a puzzle or stacking activity before the device turns on.
• Sensitivity switches are designed for students with minimal movements. They respond to the slightest muscle contraction (the ability to flex and release any muscle).
• Other Input switches depend on systems other than touch and include a change in air pressure or voice activation.

Features

There are several ways to examine a switch to determine its "match" for a student's abilities and preferences. For example, the size of the surface "target" that a student must activate is a primary characteristic. How large does the surface have to be?

Other questions to ask include:

• How small might it be?
• Which areas actually activate the switch? The center? The corners? The edges?
• What does the switch feel like? Does the student prefer a particular texture? Can it be added to the surface later?

Other features to consider include:

• The amount of force (pressure) required,
• The amount of travel that a switch has,
• The type of switch feedback when activated, and
• The durability of the switch.

Ask the student which switch he likes. It is important to let him try a variety of switches during different times of the day as his energy and comfort levels may change. For additional information, we offer a handout on switch features.

Additional Options

Remote Switches
If cords and wires are in your way, consider a remote switch where a receiver connects to the toy/device and the switch transmits information through radio waves to turn the device on.

Proximity Switch
These "no Hands" switches require simply a motion near the surface. They are sensitivity adjustable.

Taction Pads
These clear, adhesive-backed, touch sensitive pads essentially turn any object or surface into a switch. They respond to the moisture in the user's hands or fingers.

Multiple Switches
These switches are actually five switches in one. They can control any device that requires five switches for operation (i.e. directional movement).

Mounting Systems

Switches sometimes must be mounted in place to make them easier to use. This provides stability for the student by ensuring that the switch stays in one place! For push switches we often use pieces of sticky-backed Velcro to hold them in place on a table or desk. For students who access switches in other ways, a mounting system may be useful. Mounts described below hold up to 5 lbs. They are useful for mounting switches or lightweight communication aids.

Examples

E-Mount (Adaptivation)
The E-Mount provides quick and easy placement in any position. It includes a clamp and mounting plate. Both a Mini Clamp (standard unless specified) and a Clip Clamp are available. You also can receive your choice of mounting plates.

Universal Mount (AbleNet, Inc.)
It is available with either a knob or lever to securely lock all the joints in place. It clamps anywhere and is easy to adjust in a hurry.

(©2001 AbleNet, Inc. Photos courtesy of AbleNet, Inc. not to be reproduced without permission.)

MightyMount (Tash, Inc)
This mount is also easy to position, with adjustable arm length, arm angle, and switch angle. It attaches to the surface by tightening the Mighty Mount vice grip. A plate is provided to attach small switches.

Switch Interfaces

Switches can be used with anything electronic, including devices that work with batteries. However, the electronic device will need an interface to use a switch; a place the switch can be plugged in. Switches can control the flow of power to turn things on and off, such as a battery-operated toy or a radio or fan. Items that run on batteries use direct current (DC) while those with plugs use alternate current (AC). Both types can be adapted for switch use with different interfaces. With other interfaces, the same switches can also control complex electronics such as computers and telephones.

Examples of Switch Interfaces

We have also provided a useful handout explaining switch interfaces in detail.

• A Battery adapter can transform any battery operated (AC) toy or device for switch activation. (View our handout on adapting a battery-operated toy/device.)
• An Environmental Control Unit (ECU) is an interface for any electrical (DC) appliance with an on/off switch.
• A Switch Latch is connected between the switch and the target device. One touch of the switch turns the device on; the next turns it off.
• A Timer connects between the switch and the target device. The device will run for a set amount of time (from 1 to 60 seconds) after the switch is activated.
• A Switch Latch-Timer offers both features: timer and latch. It can be set to turn the tape player on for 5 seconds. The user must then re-activate the switch.
• A Series Adapter is an interface used between a target device and two switches. Both switches must be activated for the device to turn on.
• A Jack Adapter converts the size of the switch jack to match the size on the toy or interface.

Positioning Tips

For optimal switch use, several things must be considered:

1. The child should be in a comfortable position. Wherever the child is positioned, in a chair, at a table, or on the floor, the child should be secure so that she can expend energy on participation. She should not be putting effort into balancing or maintaining a particular position. Watch for signs of fatigue.

2. Place the switch near the child's preferred, most reliable access site. Reflexive or abnormal movement patterns should not be considered appropriate sites. Switch placement should not interfere with stable body positioning. Accidental "hits" are natural consequences!

3. Place the device that the child is activating in close proximity to the switch itself. The closer the switch is to the reacting device, the more concrete the cause/effect relationship is.

4. Secure the switch in a stable position so that it doesn't move out of place when activated. Special switch holders are available or items such as suction cups, Dycem (a non-slip material) or a combination of Show Loop fabric (loop Velcro) with hook Velcro adhered to the switch, will stabilize the switch.

• Mounting systems can provide more sophisticated switch securement. These can include a combination of clamps, mounts, mounting plates, rods and flexible arms. Pieces are sold separately or as systems or kits.
• Hand/arm splints, wedges or customized supports can help a student be more accurate.
• You can further customize switches to make them more appealing or functional, by adding color stickers or textures.

5. As children should be repositioned frequently throughout the day, consider more than one switch access site, mounting system, and/or switch for different activities in different positions. The stamina of the child, the environments and activity requirements will help to identify the most successful solutions.

Classroom Ideas

When starting switch use with the student, choose an activity that is motivating to him. Give the student ample time to activate the switch; wait for the response, and describe what happened. Say, "You're making that car move fast," instead of "Good hitting the switch!" This helps the student understand his ability to control action. Switches can be used throughout classroom routines. View our handout on classroom switch activities.

Examples

Paint 'N' Swirl (Ablenet)
Students run the Paint 'N' Swirl to create a variety of projects as a peer drizzles glitter paint on paper. Finished projects can be used for bulletin boards, gifts for parents, or crafts to sell.

Battery-Operated Scissors (Ablenet)
These scissors are easy to use and great for literacy activities. A "How-to" guide is included.

Polaroid(r) Impulse Camera [3-PIC]
Take instant photos for school projects. Use this adapted camera with a switch to create stories with pictures, make a permanent record of field trips, photograph people being interviewed for a school newspaper, or document the steps in a classroom activity.

All-Turn-It Spinner (Ablenet)
This switch-controlled spinner lets students participate in regular classroom activities. Easy to customize spinner overlays are available that are made with reusable vinyl stickers. They are a learning tool for basic concepts like numbers, colors, or skills such as matching, sorting and sequencing.

Team Extreme (Pathways Group)
Team Xtreme makes it possible for people with disabilities to play any Nintendo game. It is fully approved by Nintendo of America Inc., with products for the NES®, Super NES®, and N64®. Their "Smart Switches" controller is for the 'not quite ready for video games set'.

Cassette Player + Microphone (Enabling Devices)
This cassette player and recorder microphone allows sound amplification through the speakers. It accepts both 1/4" and 1/8" plugs.

Slide Projector Control Adapter (Ablenet)
Students advance slides with a switch using any Caramate or Kodak Carousel slide projector. Students can "turn pages" in a book during reading activities or run the slide projector for teachers.

Ablenet device photos used: ©2001 AbleNet, Inc. Photos courtesy of AbleNet, Inc. are reproduced with permission.

Activity Resources

Adaptivation's Application Photo Album
This site shows examples of several application ideas using Adaptivation products in a photo album format.

Recipes for Success (under 2001 Product catalog)
This is a resource guide to hundreds of practical applications for assistive technology. Each recipe gives a detailed list of materials needed, step-by-step instructions, and numerous activity and equipment variations to help adapt an activity.
Cost: $39.00 (Vol 1 and 2)

Book of Possibilities (Ablenet)
These books feature a general information section about what simple technology is and how to use it. They show detailed applications from around the world to include your student in the classroom activities. They include easy-to-follow instructions, clear examples, and simple equipment lists. There are tons of easy-to-use ways to include students in a variety of math, science, language arts, social studies, spelling and reading activities
Cost $ 26.99

Inclusive Technology
Activities using switch operated devices are offered.

Publications

Burkhart, L. J. (1980). Homemade Battery - Powered Toys and Educational Devices for Severely Handicapped Children. College Park, MD: Author.

Burkhart, L. J. (1985). More Homemade Battery Devices for Severely Handicapped Children. College Park, MD: Author.

Burkhart, L. J. (1987). Using Computers and Speech Synthesis to Facilitate Communicative Interaction with Young and/or Severely Handicapped. College Park, MD: Author.

George, C. & Lacefield, W. (2001). The Handbook of Adaptive Switches and Augmentative Communication Devices (3rd Edition). Lexington, KY: Academic Software.

Goossens, C., & Crain, S. (1992). Using Switch Interfaces with Children Who Are Severely Physically Challenged. Austin, TX: Pro-ed.

Levine, J., & Enselein, K. (1990). Fun for Everyone. Minneapolis, MN: Ablenet.

Levine, J., & Scherfenberg, L. (1986). Breaking Barriers: How Children and Adults can Access the World through Simple Technology. Minneapolis, MN: Ablenet.

Levine, J., & Scherfenberg, L. (1987). Selection and Use of Simple Technology: In Home, School, Work and Community Settings. Minneapolis, MN: Ablenet.

Wright, C. & Nomura, M., (1985). From Toys to Computers: Access for the Physically Disabled Student. San Jose, CA: Authors.