Electric field proximity sensing

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Electric Field Proximity Sensing or EFPS is a sensory system that relies on the fact that an electric field can be perturbed by the existence of a nearby object, provided it is at least slightly conductive. One type of EFPS is The People Detector. The People Detector is a micro-electronic based device that can detect the presence of both moving and stationary objects through solid materials. Its ability to operate through any non-conductive material permits complete invisibility. The sensor functions by detecting small changes in an ultra-low-power electromagnetic field generated between two remotely located antenna electrodes. Its range is adjustable from a few centimetres [inches] to 4 m [over 12 feet]. [1] Electric field proximity detectors can detect partially conducting or conducting objects and does not depend on impedance to ground. [2]

Electric field spatial distribution of vectors representing the force applied to a charged test particle

An electric field surrounds an electric charge, and exerts force on other charges in the field, attracting or repelling them. Electric field is sometimes abbreviated as E-field. Mathematically the electric field is a vector field that associates to each point in space the force per unit of charge exerted on an infinitesimal positive test charge at rest at that point. The SI unit for electric field strength is volt per meter (V/m). Newtons per coulomb (N/C) is also used as a unit of electric field strengh. Electric fields are created by electric charges, or by time-varying magnetic fields. Electric fields are important in many areas of physics, and are exploited practically in electrical technology. On an atomic scale, the electric field is responsible for the attractive force between the atomic nucleus and electrons that holds atoms together, and the forces between atoms that cause chemical bonding. Electric fields and magnetic fields are both manifestations of the electromagnetic force, one of the four fundamental forces of nature.

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Advantages

Because EF sensors provide comparatively low amounts of data, they have the potential to provide several advantages over optical systems. Electric field systems can be made smaller, lighter, and power efficient (valuable qualities in an age of ever shrinking electronics such as palm and watch based computers). Since EF sensors penetrate non-conducting materials, they can remain hidden allowing them to remain protected from weather. EFPS systems today are used in a wide variety of industrial and commercial applications, including automobile airbag systems (to determine where passengers are seated), in advanced robotic manipulators (to determine the properties of an object in the manipulator's grasp), and in home automation, to determine which rooms are occupied.

Home automation

Home automation or domotics is building automation for a home, called a smart home or smart house. A home automation system will control lighting, climate, entertainment systems, and appliances. It may also include home security such as access control and alarm systems. When connected with the Internet, home devices are an important constituent of the Internet of Things.

Electric fish

This is the same sensing system that is used by the electric catfish to navigate through muddy waters. These fish make use of spectral changes and amplitude modulation to determine factors such shape, size, distance, velocity, and conductivity. The abilities of the electric fish to communicate and identify sex, age, and hierarchy within the species are also made possible through electric fields. EF gradients as low as 5nV/cm can be found in some saltwater weakly electric fish. [3]

Electric catfish family of fishes

Electric catfish or Malapteruridae is a catfish family in the order Siluriformes. This family includes two genera, Malapterurus and Paradoxoglanis, with 21 species. Several species of this family have the ability to produce an electric shock of up to 350 volts using electroplaques of an electric organ. Electric catfish are found in tropical Africa and the Nile River. Electric catfish are usually nocturnal and carnivorous. Some species feed primarily on other fish, incapacitating their prey with electric discharges, but others are generalist bottom foragers, feeding on things like invertebrates, fish eggs, and detritus. The largest can grow to about 1.2 m (4 ft) long, but most species are far smaller.

MIT prototype

Researchers at MIT have created a prototype of a 3-dimensional EFPS called the "Fish". It can monitor objects in a 3-dimensional space. The People Detector operates in only 2-dimensions and does not have a microprocessor. [1]

Massachusetts Institute of Technology University in Massachusetts

The Massachusetts Institute of Technology (MIT) is a private research university in Cambridge, Massachusetts. Founded in 1861 in response to the increasing industrialization of the United States, MIT adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. The Institute is a land-grant, sea-grant, and space-grant university, with a campus that extends more than a mile alongside the Charles River. Its influence in the physical sciences, engineering, and architecture, and more recently in biology, economics, linguistics, management, and social science and art, has made it one of the most prestigious universities in the world. MIT is often ranked among the world's top universities.

Technology review

Technology Review , a science and technology magazine published by MIT, featured EFPS in their September 2007 computing section. Intel had created a robotic arm that could distinguish between plastic bottles that had water present or not. The robotic arm did not have to touch the bottles to determine which ones had water inside. Researchers applied an oscillating voltage to an electrode, in the thumb of the robot for example, which created an electric field. As the field interacted with the water in the bottle, special sensors could determine the change in the electric field and then cause the robot to behave in certain ways. [4]

Intel American semiconductor company

Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, in the Silicon Valley. It is the world's second largest and second highest valued semiconductor chip manufacturer based on revenue after being overtaken by Samsung, and is the inventor of the x86 series of microprocessors, the processors found in most personal computers (PCs). Intel ranked No. 46 in the 2018 Fortune 500 list of the largest United States corporations by total revenue.

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References

  1. 1 2 "(untitled homepage)". bik.com (website). Retrieved 2011-06-02.
  2. Van Schyndel, Andre J. Patent No. 6859141 2/22/2005
  3. Zimmerman, T., Smith, J., Paradiso, J., Allport, D., & Gershenfeld, N. (1995). Applying Electric Field Sensing to Human-Computer Interfaces. IEEE SIG .
  4. Greene, Kate (September 17, 2007). "Robots That Sense Before They Touch". Technology Review. Retrieved 2011-06-02.