Head-motion detectors: SmartNav 4 and Camera Mouse 2010
Another option for those who can't control a standard mouse and keyboard but do have steady control of head movements is NaturalPoint's SmartNav 4:AT, an infrared scanner that sits on top of a monitor or notebook. The $500 device connects with a Windows PC or Mac and senses head motion in a 45-degree field of view 100 times per second.
SmartNav 4 works by sensing a small reflective dot that can be stuck to the user's forehead, eyeglass frames, hat or headset's microphone; the package includes 26 reusable dots. Move your head around and SmartNav follows the motion to place the screen's pointer where you want it.
Users can type using a virtual keyboard on-screen; actions such as clicking, right-clicking and dragging are controlled with a special toolbar. The software is highly configurable, offering adjustments such as separate X and Y scaling for users with limited horizontal or vertical head motion and smoothing control for those with unsteady head movements.
A free mouse alternative for those on a tight budget is the Camera Mouse 2010 application. Developed by researchers at Boston College and Boston University, Camera Mouse replaces the Windows mouse software with a system that tracks the head's movements with a standard webcam (either built in or externally attached via USB 2.0).
After calibrating the system to a corner of an eye or the space between the nose and the mouth, the user moves his head to move the pointer around the screen; holding the pointer still on a small area of the screen activates a click. It takes some getting used to and isn't as sophisticated or precise as products such as SmartNav, but the price is certainly right. Camera Mouse requires Windows XP, Vista or Windows 7.