14-12-2012, 05:54 PM
CONSTRUCTION AND TESTING OF AUTOMATIC SECURITY LIGHT CONTROL SYSTEM USING PHOTO DETECTOR
CONSTRUCTION AND TESTING OF AUTOMATIC SECURITY.doc (Size: 923.5 KB / Downloads: 45)
ABSTRACT
One of the main components of any security system is Light. The theory stands that if an area is brightly lit, then there is a smaller chance of illegal activities such as; cult activities, immoral acts, molestations, and crime taking place because there are fewer shadows to hide in and obscured the criminals and perpetrators. In homes, light can deter burglars because the light indicates that someone is home and awake, so there is no cover. This impression is conveyed by home owners through the use of the device, like ‘AUTOMATIC SECURITY LIGHT SYSTEM’. This device automatically switches OFF at dawn with the help of a sensor ‘PHOTO-DETECTOR’ which senses the level of available light in a certain area.
INTRODUCTION
The earliest lamp were used by Greek and Roman civilization, where light primarily served the purpose of security, both to protect the wanderer from tripping over something on their path as well as keeping the potential robbers at bay. The Romans had a word LATERNARIUS which was a term for a slave responsible for lighting up the oil lamps in front of their villas and at various locations. The earliest lamps required that a lamp lighter tour the town at dusk, lighting each of the lamps, but later designs employed ignition devices that would automatically strike the flame when the gas supply was activated.
Often times there are situations where the lamp lighters are not available to carry out their assignment and inability of the ignition device to strike on the flame and also where the gas is out, hence resulting to accidents, crashes, evil acts and fatalities, especially those involving pedestrians. Hence this method is not reliable and has motivated the quest for an alternative switching method for security lights.
One of such is automatic security light control using ‘PHOTO-DETECTOR’. This device is so ideal for homes and any other place where its services would be required. It has an added advantage of being pollution free and environment friendly. It automatically switches ON and OFF the security and lighting systems of a particular place at dusk and dawn respectively.
STATEMENT OF PROBLEM
Security has been an issue which points fiercely to the face of the world today. Issues like crimes, robbery, immoral acts, molestation etc both in developed and developing communities has been on the increase as a result of poor lighting control systems. In this type of situation and to curb it to zero level a device which would automatically and on-timely control the lighting systems becomes a necessity.
AIM AND OBJECTIVE
The main aim of this project is to construct an automatic security light control using PHOTO-DETECTOR.
OBJECTIVES
- To provide a device that will automatically control the security light of any place, thus reduce the time and effort spent in turning ON and OFF of security lights.
- To reduce and probably bring to the bearest minimum evil acts such as; molestation, cult activities, rape, etc which occurs in dark areas of the campus.
GENERAL FEATURES OF DESIGN
A great important feature employed in this design is the application of the logic circuitry system which automatically switches ON and OFF the security light, hence conveying the message of ‘the presence of someone’, at dusk effort and time is what has not be in existence in the time of old. Its switching is performed within milliseconds.
SCOPE OF WORK
The scope of this project has been restricted to auto detection and switching control of the security light systems.
LITERATURE REVIEW
PHOTO DETECTORS are sensors of light or other electromagnetic energy, Enss Christian (2005). And PHOTO DETECTION in semiconductors works on the general principles of the creation of electrons-hole pairs under the action of light. When a semiconductor material is illuminated by photons of an energy greater than or equal to its band gap, the absorbed photons promote electrons from the valence band into excited states in the conduction band, where they behave like free electrons able to travel long distances across the crystal structure under the influence of an intrinsic or externally-applied electric field, Haugan (2008).
In this way the separation of electron-hole pairs generated by the absorption of light gives rise to a photocurrent, which refers by definition to the fraction of the photo generated free charge-carriers collected at the edge of the material by the electrodes of the photo detecting structure, and whose intensity at a given wavelength is an increasing function of the incident light intensity.
On this level, we distinguish between two large categories of photo detectors base on the nature of the electric field, which causes the charge separation of photo generated electron-hole pair.