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).