Wireless Based Security System Using Sensors

8/7/2019 Wireless Based Security System Using Sensors

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A Report on Wireless based Security System using Sensors

Bapatla Engineering College

Submitted by G. Raja Sekhar along with co-author K.Ramanjeyulu

professor, Baptala Engineering College, Baptala.


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Abstract:A Wireless based Security System using sensors, this is being prone to be implemented in

various big originations or Multi National Companys, where the use of systems and

highly sophisticated environments, where the cost of equipment lies in the range of

several costs. The use of system can be extended to more than for a day to day uses. It

can also be used for the transport services like Trains, Automobiles and House hold

purpose also.

Key WordsPhoto Sensors, Bluetooth device, GPS device, and software coding.

Introduction:

These days we find many of fire accidents like most recently in Hyderabad of the burnt

off a bus and fire accident occurred in Gautami Express, and also in Rajadhani Express.

In all the above cases the fire accident was occurred in different places, in spite of having

the necessary and preventive measures the accident occurred and most of the property

was lost and in certain cases the loss of death is also more.

This deliverable consists of the Desktop Radiance computer models that were used in the

simulation studies conducted at Penn State University as part of this project. These files

are provided in the form of AutoCAD .DWG files with surface and glazing materials

attached to each of the surfaces. Six different classrooms models are provided.

The project team surveyed and evaluated daylight delivery systems that have been

applied in classrooms within the state of California. From these discussions, six different

classroom arrangements were selected to apply to the study of photo sensor system

configuration and performance. Each of these systems represents a different method of

delivering daylight to a classroom space, which is likely to impact a photo sensor control

system through the different daylight distribution provided within the space. Different


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Axis Technologies Inc. to commercialize the SDH and other related technologies

including photo sensors that more accurately account for light approaching the sensor

from all angles in its field of view, rather than just head-on, and an approach that uses

dual photo sensors for increased reliability.

The SDH consists of a photo sensor to measure light levels, relays to switch the states of

the electric lights, a controller that determines when to change lighting states, and an

optional occupancy sensor. Together, these elements create a system that is reliable, user-

friendly, and cost-effective.

Self-calibrating ability. The SDH control logic uses photo sensor measurements to switch

among the off, low-output, and high-output states in a bi-level electric lighting system

(Figure2).Differences in photo sensor signals are automatically calculated every time the

lights are switched and serve to calibrate and govern the systems response. This process

accounts for changes in furniture layout and reflectance of interior surfaces, and also

enables the system to adapt to the decreasing levels of electric light that are available as

the lamps age. A time delay is programmed so that the system doesnt respond

unnecessarily to transient changes in the daylight environment. A time delay works well

for on/off systems because they are generally expected to work once in the early morning

and once in the late afternoon. The system has been tested in the bi-level lighting

configuration, but is also designed to be able to switch to any number of intermediate

light levels.

Occupant acceptance. Several features are aimed at increasing user acceptance of the

SDH system. First, the system will allow occupants to adjust the on and off setpoints to

match their lighting preferences. Sufficient separation between the setpoints will also

help to minimize the on/off cycling that sometimes annoys occupants under conventional

daylight harvesting systems. Second, an optional occupancy sensor is available for

switching only when the space is unoccupied so that occupants do not experience a

sudden drop in light levelit can take time for the eyes to adjust to sudden changes. In

addition, if sudden changes are a concern, conventional bi-level ballasts can be replaced

by ramping ballasts that gradually adjust lights from one level to the next.


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Cost effectiveness. The initial cost of the SDH system should be low because it uses a

small number of simple components and does not require the more expensive dimming

ballasts that dimming day lighting systems use. In addition, thanks to the automatic

calibration capabilities and the ability of the user to adjust set points, the system never

needs to be calibrated or recalibrated by a technician, thus eliminating the most expensive

element in current daylight-harvesting approaches.

All of these features will enable users of the SDH to reliably reap the financial benefits of

daylight harvestingsignificant energy-cost savings and reductions in peak demand

charges because peak daylight availability typically coincides with peak electricity

demand.

A GPS receiver calculates its position by precisely timing the signals sent by

GPS satellites high above the Earth. Each satellite continually transmits messages that

include

the time the message was transmitted

precise orbital information (the ephemeris)

the general system health and rough orbits of all GPS satellites (the almanac).

The receiver uses the messages it receives to determine the transit time of each message

and computes the distance to each satellite. These distances along with the satellites'

locations are used with the possible aid oftrilateration, depending on which algorithm is

used, to compute the position of the receiver. This position is then displayed, perhaps

with a moving map display or latitude and longitude; elevation information may be

included. Many GPS units show derived information such as direction and speed,

calculated from position changes.

Three satellites might seem enough to solve for position since space has three dimensions

and a position near the Earth's surface can be assumed. However, even a very small clock

error multiplied by the very large speed of light the speed at which satellite signals

propagate results in a large positional error. Therefore receivers use four or more

satellites to solve for the receiver's location and time. The very accurately computed time
http://en.wikipedia.org/wiki/Satelliteshttp://en.wikipedia.org/wiki/Ephemerishttp://en.wikipedia.org/wiki/Trilaterationhttp://en.wikipedia.org/wiki/Speed_of_lighthttp://en.wikipedia.org/wiki/Satelliteshttp://en.wikipedia.org/wiki/Ephemerishttp://en.wikipedia.org/wiki/Trilaterationhttp://en.wikipedia.org/wiki/Speed_of_light


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is effectively hidden by most GPS applications, which use only the location. A few

specialized GPS applications do however use the time; these include time transfer, traffic

signal timing, and synchronization of cell phone base stations.

Although four satellites are required for normal operation, fewer apply in special cases. Ifone variable is already known, a receiver can determine its position using only three

satellites. For example, a ship or aircraft may have known elevation. Some GPS receivers

may use additional clues or assumptions (such as reusing the last known altitude, dead

reckoning, inertial navigation, or including information from the vehicle computer) to

give a less accurate (degraded) position when fewer than four satellites are visible.

Position calculation introduction

To provide an introductory description of how a GPS receiver works, error effects aredeferred to a later section. Using messages received from a minimum of four visible

satellites, a GPS receiver is able to determine the times sent and then the satellite

positions corresponding to these times sent. The x, y, and z components of position, and

the time sent, are designated as where the subscript i is the satellite number and has the

value 1, 2, 3, or 4. Knowing the indicated, or uncorrected, time the message was

received (tr, uncorr), the GPS receiver can compute the uncorrected transit time of the

message as . Assuming the message traveled at the speed of light, c, the

uncorrected distance traveled or pseudorange, can be computed as .

A satellite's position and pseudorange define a sphere, centered on the satellite, with

radius equal to the pseudorange. The position of the receiver is somewhere on the surface

of this sphere. Thus with four satellites, the indicated position of the GPS receiver is at or

near the intersection of the surfaces of four spheres. In the ideal case of no errors, the

GPS receiver would be at a precise intersection of the four surfaces.

If the surfaces of two spheres intersect at more than one point, they intersect in a circle.The article trilateration shows this mathematically. A figure, Two Sphere Surfaces

Intersecting in a Circle, is shown below. Two points where the surfaces of the spheres

intersect are clearly shown in the figure. The distance between these two points is the

diameter of the circle of intersection.
http://en.wikipedia.org/wiki/Time_transferhttp://en.wikipedia.org/wiki/IS-95#Physical_layerhttp://en.wikipedia.org/wiki/Dead_reckoninghttp://en.wikipedia.org/wiki/Dead_reckoninghttp://en.wikipedia.org/wiki/Inertial_navigation_systemhttp://en.wikipedia.org/wiki/Speed_of_lighthttp://en.wikipedia.org/wiki/Trilaterationhttp://en.wikipedia.org/wiki/Time_transferhttp://en.wikipedia.org/wiki/IS-95#Physical_layerhttp://en.wikipedia.org/wiki/Dead_reckoninghttp://en.wikipedia.org/wiki/Dead_reckoninghttp://en.wikipedia.org/wiki/Inertial_navigation_systemhttp://en.wikipedia.org/wiki/Speed_of_lighthttp://en.wikipedia.org/wiki/Trilateration


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The intersection of a third spherical surface with the first two will be its intersection with

that circle; in most cases of practical interest, this means they intersect at two

points. Another figure, Surface of Sphere Intersecting a Circle (not a solid disk) at Two

Points, illustrates the intersection. The two intersections are marked with dots. Again the

article trilateration clearly shows this mathematically.

Surface of sphere intersecting a circle (not a solid disk) at two points

For automobiles and other near-earth vehicles, the correct position of the GPS receiver is

the intersection closest to the Earth's surface. For space vehicles, the intersection farthest

from Earth may be the correct one.

The correct position for the GPS receiver is also the intersection closest to the surface of

the sphere corresponding to the fourth satellite.

Two sphere surfaces intersecting in a circle
http://en.wikipedia.org/wiki/Trilaterationhttp://en.wikipedia.org/wiki/Trilateration


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Surface of sphere intersecting a circle (not a solid disk) at two points

Correcting a GPS receiver's clock

One of the most significant error sources is the GPS receiver's clock. Because of the very

large value of the speed of light, c, the estimated distances from the GPS receiver to the

satellites, the pseudoranges, are very sensitive to errors in the GPS receiver clock; for

example an error of one microsecond (0.000 001 second) corresponds to an error of

300 meters (980 ft). This suggests that an extremely accurate and expensive clock is

required for the GPS receiver to work. Because manufacturers prefer to build inexpensive

GPS receivers for mass markets, the solution for this dilemma is based on the way sphere

surfaces intersect in the GPS problem.

It is likely that the surfaces of the three spheres intersect, because the circle of

intersection of the first two spheres is normally quite large, and thus the third sphere

surface is likely to intersect this large circle. It is very unlikely that the surface of the

sphere corresponding to the fourth satellite will intersect either of the two points of

intersection of the first three, because any clock error could cause it to miss intersecting a

point. However, the distance from the valid estimate of GPS receiver position to the
http://en.wikipedia.org/wiki/Speed_of_lighthttp://en.wikipedia.org/wiki/Pseudorangehttp://en.wikipedia.org/wiki/Speed_of_lighthttp://en.wikipedia.org/wiki/Pseudorange


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surface of the sphere corresponding to the fourth satellite can be used to compute a clock

correction. Let denote the distance from the valid estimate of GPS receiver position to

the fourth satellite and let denote the pseudorange of the fourth satellite.

Let . is the distance from the computed GPS receiver position to the surface

of the sphere corresponding to the fourth satellite. Thus the quotient, , provides

an estimate of (time indicated by the receiver's on-board clock) - (correct time),and the

GPS receiver clock can be advanced if is positive or delayed if is negative. However,

it should be kept in mind that a less simple function of may be needed to estimate the

time error in an iterative algorithm as discussed in theNavigation equations section.

Diagram depicting satellite 4, sphere, p4, r4, and da

Structure

The current GPS consists of three major segments. These are the space segment (SS), a

control segment (CS), and a user segment (U.S.). The U.S. Air Force develops,

maintains, and operates the space and control segments. GPS satellitesbroadcast
http://en.wikipedia.org/wiki/Global_Positioning_System#Navigation_equationshttp://en.wikipedia.org/wiki/Broadcast_signalhttp://en.wikipedia.org/wiki/Global_Positioning_System#Navigation_equationshttp://en.wikipedia.org/wiki/Broadcast_signal


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signals from space, and each GPS receiver uses these signals to calculate its three-

dimensional location (latitude, longitude, and altitude) and the current time.

The space segment is composed of 24 to 32 satellites in medium Earth orbit and also

includes the payload adapters to the boosters required to launch them into orbit. The

control segment is composed of a master control station, an alternate master control

station, and a host of dedicated and shared ground antennas and monitor stations. The

user segment is composed of hundreds of thousands of U.S. and allied military users of

the secure GPS Precise Positioning Service and tens of millions of civil, commercial, and

scientific users of the Standard Positioning Service (see GPS navigation devices).
http://en.wikipedia.org/wiki/Broadcast_signalhttp://en.wikipedia.org/wiki/Medium_Earth_orbithttp://en.wikipedia.org/wiki/Ground_antennahttp://en.wikipedia.org/wiki/GPS_navigation_devicehttp://en.wikipedia.org/wiki/Broadcast_signalhttp://en.wikipedia.org/wiki/Medium_Earth_orbithttp://en.wikipedia.org/wiki/Ground_antennahttp://en.wikipedia.org/wiki/GPS_navigation_device

Wireless Based Security System Using Sensors

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