Consumer electronic devices have now become a part of everyday life. Gone are the days when mobile phones were a rarity and PDAs could be afforded by a minority. With these embedded electronic devices becoming ubiquitous, manufacturers of such devices are finding new ways of packing more features and functionality to enhance their usability and be more competitive in the market.

One such feature that is finding its way into a number of embedded devices is proximity sensing. Proximity sensing in the world of embedded devices is the detection of the presence of a human finger or hand near an electronic gadget. This feature of proximity sensing is being adopted by numerous industries for a variety of applications.

Use of Proximity Sensing
Proximity sensing has found immediate adopters in the hand-held, battery- powered devices industry. The feature is seen in the latest mobile phones and music players. The primary function of proximity sensing in these devices is power saving.

The LCD display on the music player or phone remains off as long as it does not detect the presence of a human finger or hand near it. As a result of the display staying off, only the CPU draws power from the battery and power is not drawn to drive the LCD display.

As soon as the device detects the presence of the human hand, the display illuminates, showing either the present song being played or caller information. The average power consumed is thus reduced, thereby increasing battery life.

Proximity sensing has become a common feature in home automation. It is used to turn on table lamps by waving a hand in front of it. Water faucets turn on when the hand is placed under it.

Microwaves and refrigerators with displays on them remain blank as long as a user is not in its vicinity. When a user nears it, the display and lights turn on. New home automation systems are also adopting this feature. Touch screen displays used for lighting and appliance control are configured to behave as a digital photo frame under normal circumstances.

As soon as someone nears it, it changes its display to its control panel and illuminating hidden touch sensor buttons. Proximity sensing can also be used for security by setting off an alarm if it detects an unauthorized presence either near a door knob or a window pane. Extend this idea to building smarter utensils and appliances.

Utensils that could indicate the temperature of the liquids inside it by changing surface color when a hand neared it. This could save children from nasty burns around the kitchen. Bath tubs that could warn you that the water is too cold even before you put a foot inside it.

Proximity sensing can be adopted by the automobile sector to build smarter cars. Envision a car that sensed a driver in its vicinity and unlocked the door for him as he approached the handle. Apart from this, it would turn on the ignition and the AC or heater based on the temperature inside the car. The car would warn the driver if the handle or the shifters were too hot when his hand approached it.

It could also instruct the driver what a knob or a button in the car did if it detected the presence of his hand near it. Just when you thought cars could not get any smarter, emerging technology such as proximity sensing is stretching the limits.

Proximity sensing is used to display hidden touch sense buttons in keyboards. Mice remain in sleep mode until it detects the presence of a hand. It then wakes up, turns on its radio to pair with the PC and is ready for operation. This allows for better battery life. Proximity based buttons could replace mechanical buttons to open laptops when shut. This could be extended to include refrigerator doors, microwaves and cell phones.