By Silicon Laboratories (www.silabs.com)

More than a billion electronic products with advanced human interfaces capabilities are expected to ship in 2010. Based on technologies such as capacitive and infrared proximity sensing, these interfaces provide a dramatic improvement in the end-user experience while increasing system reliability and reducing total cost.

In addition to making products easier to use and more visually appealing, they mask the increasing underlying complexity of electronics, enabling manufacturers to bring products with advanced capabilities to the mass market faster.

Advanced sensor-based interfaces are more reliable than traditional mechanical interfaces since they do not contain moving parts associated with buttons and dials, which are prone to failure over time. Sensor-based control panels and displays also become more flexible, allowing a single set of controls to be reconfigured based on application context so that users are presented with only those choices that are currently active.

When combined with gesture recognition and “touchless” technology, developers can add intelligence to device interfaces that anticipates user needs and enables innovative usage models that make products friendlier and more intuitive to use. Flexible firmware can be adjusted quickly and easily as market needs change without having to completely re-architect systems or redesign device packaging.

Next-Generation Human Interfaces
Next-generation products require next-generation human interfaces to differentiate themselves in the marketplace. By making electronics devices more aware of their environment, new features can be implemented that enhance ease-of-use, improve power efficiency and reduce system cost. In addition, high sensitivity, low noise and resistance to moisture ensure reliability in even the most challenging environments.

Two of the primary technologies driving next-generation interface development are capacitive and proximity sensing. Capacitive sensing detects the presence of a human finger through changes in the capacitive value of the sensing element. It enables advanced controls such as sliders and wheels and is well-suited for close-range interfaces where users are used to physical feedback such as when they press a button. Proximity sensing uses infrared sensors to calculate the distance of objects up to 1 meter away using infrared reflectivity techniques. Proximity sensors also can place an object in space, enabling “touchless” gesture tracking.

Using these two technologies together enables finer tuning of user interfaces. Many end users are already familiar with capacitive sensing technology from its use in a wide array of consumer products, most prominently the iPod and iPhone. Until recently, proximity sensing has typically been used for simple tasks such as cheek detection in handsets.

However, it can be used for so much more:
• User detection: Proximity sensing can determine, for example, whether an end user is currently sitting at a PC and turn off the display when he or she walks away from the desk. Given the substantial power required for LCD backlighting, even simple user detection can result in significant power savings across an organization. User
detection also can be implemented in devices such as USB chargers or thumb drives so that devices can prepare themselves for sudden removal.
• Fingerprint-free displays: Many portable devices require users to touch buttons all over the screen, leaving oily marks that are both difficult to see through and clean. A touchless interface for a portable multimedia player, for example, would eliminate the need for users to touch the very screen on which they want to watch a video. Similar
applications include enabling users to flip through the pages of an electronic cookbook with touchless ease or allowing doctors to directly interact with touch screen-based systems during surgery without fouling the screen with fingerprints.
• Automatic backlighting control: Part of the proximity sensing signal path is the use of an ambient light sensor (ALS) to reduce noise from external light sources. This same sensor also can be used to monitor background lighting conditions and automatically adjust the display backlight appropriately to reduce power consumption.
• Invisible intrusion detection: Reflecting infrared light off the interior door surface of a system allows developers to deploy an “invisible” intrusion mechanism that avoids the unreliability and expense of mechanical switches.

For details, click http://www.silabs.com/Support%20Documents/TechnicalDocs/Capacitive%20and%20proximity%20sensing_WP.pdf?mkt_tok=3RkMMJWWfF9wsRoluqzNZKXonjHpfsX%2F7e8qUbHr08Yy0EZ5VunJEUWy2YIBSNQhcOuuEwcWGog80wVUG%2BKG