People with severe physical disabilities have very limited access to the web and computer applications when those disabilities limit their ability to operate a conventional computer keyboard and mouse. While some devices emulate the mouse or keyboard (such as head trackers ) other users can operate only one or more simple switches with gross motor actions. These users are traditionally supported with Overlay or OSK programs that sit between the user and the applications acting as an intermediary grid of ‘buttons’. These ‘buttons’ are operated by ‘stepping’ from one to another and then selecting and activating a button of interest in order to perform an action or input some text in the target application. Various ‘scan’ modes allow different combination of switches and select strategies depending on the user abilities.

Jambu Features

Jambu removes the need for these intermediate overlays by allowing the user to navigate directly around the controls in a programs User Interface and then to activate a specific control. A highlight on the screen displays which control is currently selected. Text is entered using a traditional On Screen Keyboard OSK and currently GOK is supported.

  • Lack of the level of abstraction introduced with overlay software which removes a barrier for many potential switch users (such as those who have had a stroke, or with cerebral palsy, other learning difficulties, or simply lack of familiarity with PCs, such as the elderly or very young).
  • Jambu directly highlights the area of the screen in which the user is interested. The user’s attention is not diverted to other intermediary software that is controlling scanning (which can be a barrier to using hardware like head-pointers or eye-tracking).
  • Screen highlight is customisable

Jambu in Operation

A red coloured highlight box is superimposed over an interface element (IE) [ed: sorry] which is the selected element. The user can navigate around a group of related IEs selecting each in turn. If the SE is a container (e.g. menubar item) the user can drill down into it by activating it. Otherwise if it is an actionable element activating performs the associated action (assuming only 1). In addition it is possible to navigate to the parent/containing element and the highlight changes to indicate that if activated navigation will return to the enclosing group. If the Interface Element requires text input form the user the GOK OSK is displayed.


Jambu has been funded my Mozilla Foundation accessibility grants and we are very grateful for Mozilla for making the work possible. The idea for Jambu came about when Arron Leventhal, then lead of Mozilla Accessibility, invited Steve Lee to the 2006 Boston Mozilla and GNOME accessibility summits in order to meet the community and decide on a project. Steve was keen to work on something for people using Alternative Input devices and the initial plan for Jambu as a flexible SVG OSK framework was born. After a couple of dead end investigations a prototype was created and after review Jambu was redesigned into it’s current form and Eitan Isaacson joined the project as a mentor. After a pause while other work was persued weare now looking for funding in order to continue the work and make Jamb a product.

Technical Details

Jambu is a GTK application written in Python and uses pyatspi to access the AT-SPI accessibility platform. Firefox and many GNOME applications support AT-SPI so can be accessed by Jambu. It also use pygame in order to interface with switches. It uses librsvg to draw the SVG highlight through cairo.

Our Mascot

Our family pet parrot Mozart is standing in while we’re waiting for a mascot.

A toy parrotA toy parrot on a man shoulder

Note: This is the end of the usable page. The image(s) below are preloaded for performance only.