Intelligent Lighting: Proximity detection with fluorescent lamps
Over half of the artificial light produced in the United States comes from lamps in which an electric discharge through a gas is used to produce illumination. Lighting consumes between 25 and 75 billion dollars worth of electricity annually in the US alone. The prevalence of electric discharge illumination has led us to consider ways to inexpensively use discharge lamps and other power electronic loads to enhance energy savings in buildings.
Professor Steve Leeb and his group are expanding the “dual-use” of conventional fluorescent lamp fixtures first demonstrated with Talking Lights. This new application modifies a conventional fluorescent lamp fixture to serve as a proximity detector that can register the presence, and perhaps other details, about people near the fixture. In addition to optimizing the use of energy for lighting, this information can be used for fine-grain occupancy detection to control the building HVAC system and optimize energy consumption.
Ideally, lights would automatically dim and brighten as people moved through the building. In a sparsely populated hallway, a person should travel in a “pool” of light. In areas with greater population, the lights should remain on to support occupants. Proximity detection schemes for lighting are potentially energy conserving but notoriously unsatisfactory in terms of lighting performance. The proximity sensors are difficult and expensive to install, and leave people “waving their hands” to keep the lights on.
With EECS graduate students John Cooley, Al Avestruz, and Amy Englehart, Leeb is demonstrating that fluorescent lamp fixtures can be used as proximity sensors to detect people. People have dielectric properties that disturb the electric fields around fluorescent lamps. These disturbances can be used to detect the presence of people, and will permit a lamp to automatically detect people by their dielectric presence regardless of whether or not they are moving. This detection scheme may also be useful for determining the presence of metal weapons or tools on a person. We expect to demonstrate detection in a range at least 8 to 12 feet around a fixture. An array of lamps in a room can be used to create a broad area tracking system. This scanning system can be used to optimize the energy consumption of building HVAC based on occupancy. It can also be used for security applications.
Read more:
|
