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Student Design Project: Off Screen Keyboard



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This team project between Invotek and University of Arkansas Computer Science students developed a new keyboard for people who cannot use their hands to type on standard keyboards. Special access methods like head trackers offer people who cannot use their hands a way to control the computer mouse using head movements. Special software-based “onscreen” keyboards are generally used to give the person head tracking a way to enter text into a computer. There are two problems with this approach. First, the onscreen keyboard takes up valuable space on a person’s monitor and must be moved out of the way regularly. Second, software-based onscreen keyboards don’t work as reliably as hardware-based keyboards because they trick the operating system into thinking keys were entered by a hardware device.


To develop a hardware USB keyboard that can be accessed with head movement. InvoTek engineers will support the university student team.


1) The keyboard should be easy for people to use with a head tracker.

2) The keyboard should send keys to a computer using standard USB keyboard protocols.

3) The keyboard will be acceptable to a client with high spinal cord injury.


1) Meet with client to learn about his computer access needs and to understand his abilities and limitations.

2) Design a keyboard that provides visual feedback when a key is activated by head pointing using dwell.

3) Design the required circuitry and printed circuit board.

4) Design the microcontroller software.

5) Test the system with client.

6) Report on results.


A working USB keyboard was designed and the client was successful at using it.