Georgia Tech Research Institute
 
Accessibility Assistant

Accessibility Assistant

Issues

Pointing Devices: Issue 4 of 5

Issue: Some touchpads do not respond to materials other than skin.

A touchpad is shown.  A user is attempting to interact with the touchpad using a manipulation stick with a rubber pencil eraser on the end of it.

Some users with upper mobility impairments may use a pencil eraser, mouth stick, prosthetic limb, or other device other than their fingers to interact with the touchpad. However, some touchpads will not respond to touches from rubber or plastic implements.

Two types of touchpad technology are in use. The older type, which is rarely used anymore, is the resistive touchpad. This type of touchpad consists of two membranes. When pressure is applied to the outer membrane, it contacts the inner membrane and the position of contact is detected. Because this type of touchpad relies on pressure to detect touch, the material with which the pressure is applied is irrelevant. The newer type is the capacitive touchpad. This type of touchpad detects touch based on electrical properties of the object that is touching the pad. Certain types of objects (e.g., the tip of a pencil, gloved fingers, or even sweaty fingers) do not produce detectable touches.

Populations Impacted: Users with upper mobility impairments.

Potential Solutions:
  • Provide a touchpad that will respond to a variety of materials. If possible, ensure that the touchpad will respond to touches from implements other than fingers.

  • Provide an interface that does not require the use of a touchpad. Provide an interface instead of or in addition to the touchpad that will better accommodate users with upper mobility impairments. For example, provide a set of hardware controls that allows users to use arrow keys to move a highlight cursor among the various on-screen controls, and provides a button for selection of the highlighted item.

Applicable Guidelines:
Section 508 - 1194.31(f)
Section 255 - 1193.51(c)
HFDS - 6.4.1.1
EITAAC - 5.2.1.14.1