This chapter discusses the review of related literature and review of related studies. It shows the saltcellars, differences, as well as the synthesis of the study to compare the different studies conducted and help the researchers achieve their goal respectively. A Technical Explanation on How the System Works An electronic door security system employs an input console having two readers for enhanced security.
A microprocessor processes inputs applied at each of the readers o selectively permit access through secured doors. The electronic lock assembly comprises a lock controller and multiple access code readers. The lock controller and the access code readers are powered from an on-board power source, such as the battery source. The lock controller Is programmable and has an associated memory. The memory stores valid access codes for comparison with access codes entered Into either of the readers. One of the readers is preferably a keypad.
The keypad receives personal access codes. The second reader is an electronic “kef’ reader, such as a card reader, a intact activated reader port and/ or a computer data port which also receives a personal access code. The lock controller compares an entered user access code from either reader to corresponding valid user access code from either reader to corresponding valid user access codes stored In the lock controller memory. An appropriate comparison cause the lock controller to generate a signal to the locking mechanism that places the door In an unlocked state.
The electronic lock assembly of the Invention Is responsive to either entry of personal access code at the key pad or contact by an electronic “key t the electronic reader. In the study Alarm systems were already used from the beginning. In Boston in 1851, the first McCullough loop telegraph-type alarm system was installed. These systems involved sending a 20-mill-amp current down a loop of wire and monitoring the current on the wire. If there were any change in current, it would cause a relay to change state or move a pen on a paper tape, sending a coded message.
These were also heavily used in police and fire pull stations. Early intercom systems date back to the asses. The first magnetic stripe access control cards appeared in the asses. In 1961, the London police began using closed-circuit television (CATV) to monitor actively In train stations. All of these were discrete, Individual systems. For example, there were no camera switchers, but each camera reported to an Individual monitor. Taping video was not done because it was too expensive.
Alarm recording was done The second generation of access control systems networked eight card readers together to a dedicated computer that was approximately the size of a huge early electronic desk calculator. There were typically a pair of keypads, a nixing tube display, and a 3-in. Paper tape. When a person presented a card to the front door of a facility, one would hear the paper tape chatter and the nixing tubes would display something like CICS-GAG. One would then refer to a book that would indicate that card ICC was granted access to door 1 .
The second generation of alarm systems replaced the difficult to read meters and paper tapes with colored lamps and an audible. Each alarm had three colored lamps ?green for secure, red for alarm, and yellow when bypassed. There was a switch to bypass the alarms. The second generation began in approximately 1945 and continues today. CATV systems were still little used, but intercom systems were becoming slightly less than obscure. The third generation began in 1968 and continued until approximately 1978.
Third-generation systems combined alarm and access control into one system. Up to 64 card readers and up to 256 alarm points were wired individually back to a PDP-8 or IBM Series 1 minicomputer with core memory, a [email protected] terminal, and a line printer. A basic 16 card reader system could cost more than $100,000. During this time, CATV began to be used by corporations and there were a few instances of intercom systems. In 1971, Intel introduced the first 4-bit microprocessor, the 4044, designed by Intel designer Ted Hoff for a Japanese calculator company.
The processor boasted more than 2300 transistors?more switches than MANIAC had, which filled an entire room and required a dedicated air-conditioning system Just for the computer. The 6502 and 8088 8-bit microprocessors soon followed. These became the basis for a new breed of alarm and access control system technology called distributed controller systems. Until 1974, each alarm and access control field device was wired individually back to he minicomputer, where a Jumble of wires fed into custom-made circuit boards. All that wire was costly and often cost-prohibitive for most organizations.
In 1974, one of the first distributed controller microcomputer-based alarm and access control systems was christened (by [email protected]). It brought for the first time the ability to multiplex alarms and card readers into controller panels and network panels together into a distributed system. This was a radical change. Finally, the cost of wiring, which was a major cost of early systems, was dramatically reduced. The earliest fourth-generation systems still terminated all Hess controllers into a central minicomputer, computer terminal, and line printer (early Cracked 2000 system).
The computers often had what I like to call a “user-surly’ interface. When a person presented a card at the front door, the terminal still dutifully displayed something like “CICS-GAG” as the line printer chattered the same The problem with alarm and access control systems was that their manufacturers thought they were making alarm and access control systems. What they were actually making was programmable logic controllers (Plus), which were equipped with an alarm and access control system database. This is an important distinction because in their failure to understand this, they clung to PROM architecture.
Although Proms solved the industry early problems of high memory costs, as memory costs plummeted, the industry confined its systems to the functions that its designers imagined for each box and implemented into the PROM in the controller box. REVIEW OF RELATED STUDIES Motion detectors are one of the key sensors in most home security systems. Since the object of home security is to detect an intrusion and intrusion means the unwanted residence and movement of an intruder, it stands to reason that a motion detector is essential to any well-planned security system.
In many descriptions of motion detectors, you will often notice that the detector is either active or passive. This defines the kind of detection the system will give you – or more precisely, how the detector works. Active Sensors An active motion detector emits sound, light, or other forms of energy into the zone and waits to detect change by reception or reflection. A photosphere, for example, is an active light sensor. It emits light across a path. Movement across its emission path riggers the sensor because the object creating the movement reflects light back into the sensor.
It is this reflection that causes the active detectors to activate alarms, lights, or even (as in the case of stores) open doors. Some of the more popular forms of active motion detectors are photoelectrons, radar, and ultrasonic sound sensors. 1) A photosphere, as stated above, releases light onto a certain path and waits for an object to reflect the light back into the sensor. 2) Radar uses microwaves to trigger the system. It sends out the microwave radio energy into its path and waits for an object to reflect the energy back into it. ) An Ultrasonic sound sensor employs the same theory as the previous two but by the use of sound instead of light or microwaves. The ultrasonic sound sensor waits for an ultrasonic echo reflected off a body entering within its range. With active sensors, there are really two applications. The first is what we have seen above: activation through reflection. The other is activation through disturbance. Most security and safety sensors base their alarm triggering on the “echo” or reflection mode, but there are some systems that require disturbance of a constant reflection to prompt the alarm.
These latter kinds have a specific pathway in which a mirror or an object acting as a mirror reflects the energy back into the system. This system is triggered when the energy path is disturbed and the energy is not reflected back. Passive Sensors The majority of home security motion detectors are passive. Passive sensors work on a different principle. They use infrared light as a means of measuring temperature change instead of waiting for reflection. These sensors are also called PRI (Passive Infrared) or ferroelectric sensors. Because temperature is always changing, PRI encores are set to detect rapid temperature change.
This works in the case of both seconds and within a few inches, fires alter temperatures drastically, sometimes as much as hundreds of degrees. PRI heat detectors operate by sensing sudden temperature change – 1 5 0 / second – or by sensing temperature change above a set temperature. For sensing intrusions, PRI systems have to be significantly more precise. Since infrared energy is heat, it is understandable that humans emit infrared energy. But the infrared wavelengths coming from a human body is very minute – about 9 or 10 micrometers. The PRI motion sensors have to be extremely precise and sensitive to detect human presence.
For this reason, PRI motion detectors are set to detect infrared wavelengths of about 8 to 12 micrometers. Because of the sensitivity demanded in the change, the sensor will not trigger an alarm when room or outdoor temperature changes due to slow environmental change, such as day to night, or season to season. Even more astounding is the ability of some PRI sensors to detect wavelength difference between human and animals – based on size. Since bigger animals and humans emit more heat energy than smaller animals, pet-tolerant PRI sensors are designed to distinguish between humans and smaller animals (up to around 80 lbs).
This neat configuration, making the system perfect for rural areas and homes with pets that wander freely, allows pets or small animals to cross the path of the sensor without activating any alarm. Sensor Range Most security motion detectors send out a spray of energy with a wide range of coverage. This spray of energy allows the sensor to “see” a large area. The sensor’s wide range creates a greater chance of detection and, depending on the sensor, a better chance of reflection or temperature change sensitivity. Creating a wide range of sensitivity is made possible through the sensors lenses.
The ability to focus or scatter the energy beam is based on the curvature of the lens. This scattering or focusing allows the sensor to detect motion either passively or actively in that area. Alerting to Emergency When the active or passive sensor has determined an environmental change, its action from that point on is fairly simple electronics. The sensor connects an electronic circuit in its system that allows the system to sound an alarm or activate lights or perform whatever activity the system is designed to do. The most effective motion detecting systems, however, do not stop here.
For better efficiency in the motion detector, it is best to connect the sensor to a monitored control panel that is programmed to inform you and the local law enforcement of an intrusion or fire department of a fire. With a monitored security system, the motion detector has the ability to sound two alarms: one for home and one for a dispatcher. LOCAL STUDY In the project proposed by P. Ocarina on “Coded Intruder Alarm System” et. Al. March 2007, security was highly appraised. Its purpose is specialized on protecting valuable wings for larger establishments.
Operated by an input password, the alarm system consist of three (3) components: the control panel with a keypad, a sensor, and an alarm. It is supplied by a source-output power from an alternating current (AC) source instead of using batteries, but in case of emergencies like brown-outs, battery is incorporated. In similarity with our study, security system will also be incorporated system also consists of a control panel, a sensor, and an alarm. The difference between the two studies is that the control system in our study incorporates a time go system.
On the study of K. Coat. About “Electronic Ignition & Combination Lock for Security System” et. Al. March 2005, it was mentioned that the device improves the high speed performance of the gears of the cars, ignition of the engine with the combination lock at the same time giving the owner a protection from crappers. The project will target the security & efficiency of 4-wheeled vehicles by using the combination lock and electronic ignition respectively. The purpose of our system and the “Electronic Ignition & Combination Lock for Security System” is maintaining security.
Another study is the “Ultrasonic Motion Detector Using Multiple Outputs” by Caber, Operated for the same purpose with our study, to add protection on valuable apparatus for the laboratories. Hence, the sensor used in the project is an ultrasonic transmitter. Once the room is in idle mode, the Ultrasonic Motion Detector is in green light. But when something moved, the detector activates all multiple outputs to signal alarm: turning lights from green (idle) to red and triggering the alarm. Similarities with our system from the Ultrasonic Motion Detector with Multiple
Output is that it runs detection for the purpose of security. Both uses a detector/ sensor as input and an alarm as output. Hence the system by Caber used multiple outputs, our system used an alarm and lighting as its medium for apprehension. SYNTHESIS OF THE STUDY The design project entitled ” ” was developed by relating all information gathered by the researchers. The related literature and studies showed a brief overview of” ” and its function to the project. All discussed studies provides great assistance to the proponents for during the step by step planning, designing and implementing the design project.