Characteristic of Infrared Radiation - Essay Example

Leading Header: Security Devices     Your name   Course name      Professors’ name     Date OUTLINE Introduction Characteristic of Infrared Radiation Emission of Infrared Light Advantages of Infrared Detectors Disadvantages of Infrared Detectors Application of Infrared Radiation in Security Detectors Microwave detectors Microwave Radiation Operations of A microwave detector Disadvantages of using a microwave detector Photo-electric beam detectors Characteristics of visible light Advantages of Photo beam detectors Conclusion     INTRODUCTION             Security systems consist of electronic alarms designed to alert individuals and part of thee authority about oncoming source of danger. Inside the security systems, are sensors linked to a control console through wire connections. There could also be linked through electromagnetic wave signals that are associated together to a response gadget. Most security detectors function as motion detectors placed on windows and doors to signify the presence of an oncoming person or object. Some devices are used for fire detection as well as for intrusion (Purpua, 2002). Each security detector has a different user interface, ranging from just simple noise producers to more intricate and complex devices that integrate both software and hardware with a console for monitoring purposes. These days there are a number of other security devices that utilize different techniques in detecting intruders. While others employ light, others like the ultrasound detectors use sound in order to fend off intruders (Philips, 2002).                       The most widely used security detectors in the field of risk aversion employ passive infrared and microwave detectors that utilize measurements taken from the intensity of radiation received from items that could be in its field of view (Purpua, 2002). These sensors are used in the manufacture and assembling of motion detectors. Successful detection is achieved when a source such as human beings bypasses another source such as a door or window. Since the two objects will emit different intensities of electromagnetic radiations, the sensors are able to detect this and relay this information to the control boards as intrusion (Reid, 2005). We are first going to discuss about security devices that use infrared radiation as its intrusion technique. Characteristic of Infrared Radiation             Infrared radiation which is sometimes shortened to IR, is part of the larger broader electromagnetic spectrum that includes, radio waves, visible light, microwaves among others (Barnard, 2001). IR radiation exhibits wavelengths of 0.7-300 micrometers and also displays a frequency range of between 1-430 Terahertz. This wavelength is of a greater wavelength than that of visible light. The infrared radiation is further divided into 3 categories based on the length of the wavelengths: Near Infrared: This form of radiation closely resembles visible light in characteristics, with wavelength of approximately between 0.7-1.3 microns. The second category is Mid Infrared whose wavelength is between 1.3-3 microns. It is important to note that these two categories of infrared radiation are widely used in a number of electronic devices. The third and last category that constitutes Infrared radiation is the thermal infrared, which takes up a big part of the infrared radiation spectrum (Barnard, 2001). It displays wavelength characteristics of 3-30 microns. Another important point to note is that when the first two categories are reflected by objects or items, thermal infrared is rather emitted from objects as a result of actions taking place on the atomic stage (Barnard, 2001). Emission of Infrared Light             Researchers and scholars have shown us that atoms are always mobile and constantly shifting while at the same time vibrating and rotating in all directions in relative to each other. Atoms possess differing energies and this contributes to the difference in excitation states. The difference in excitation states depends on the level of energy applied to an atom. If lots of energy is applied, the atom can depart from its ground energy level and shift to an excited level. The amount of the shift greatly depends on the quantity of energy applied to the atom. This energy can be applied through various forms such as heat or through electrification (Koryu, 2001). Within the atoms are protons and neutrons that are enclosed by a cloud of electrons. If energy is applied through electricity or any other source of energy such as light, there is a movement of electrons from the lower orbital to the higher orbital and hence shifting further and further away from the nucleus of the atom.  When this electron again shifts to a lower ground state, it does so with further liberation of a photon which is the unit particle of light. This phenomenon is replicated in all our daily activities such as when a heating coil turns red after application of electricity through it. The color normally displayed is as a result of the atoms being excited. The emitted energy is manifested through photons and this photon has a particular color of very precise wavelength which is highly dependant on the amount of energy emitted when the photon is let loose (Koryu, 2001).             Any life form in the world utilizes energy and this result in the production of heat which is later transferred to the object or items itself (Fraden, 2004). When this occurs, photons are ejected in the thermal infrared spectrum. This directly means that a rise in temperature of the object, consequently results in the emission of infrared photons with characteristic shorter and shorter wavelengths (Fraden, 2004). When this temperature becomes too hot, the object starts to emit photons in the visible region of the electromagnetic spectrum. As the temperature increases, then the transition of photons will move from the red up to white to indicate the objects is exceptionally hot. Advantages of Infrared Detectors             Infrared radiation or energy is the most straightforward and earliest form of radiation energy that is used in the manufacture of security detectors (Sinclair,2001). This energy has been used in the assembly of various simple but very efficient security motion devices. These days we have the modern Active beam motion detectors which detect intrusion by emitting a beam of infrared light along and across a room or an enclosed area. The beam is further enhanced and spread out to other areas through the use of light receivers. Use of passive mode detectors can have a major effect on cost savings for individuals and companies as they consume less energy in their operations and they are also cheap to purchase when compared to active beam detectors. They use less energy as they exclusively depend on the intensity of received light in order to detect whether there is an oncoming intruder (Sinclair,2001). This means that they don’t have to use energy in sending out beams at frequent rates. They also have lesser margin for error as they rely on a drop of the intensity of light in order to activate, unlike the other security detectors that rely on the intensity of the received beam. The range of detection of the device can also be enhanced so that it is able to detect intrusion issues much farther. With addition of Fresnel lenses to the devices, plus additional convex and concave lenses into the device, the area of coverage can be made to be wider and hence deter intruders (Bingegeli, 2003). Disadvantages of Infrared Detectors              As much as the detectors are cheap and very easy to use, the infrared radiations being used in infrared detectors have been found to turn translucence into cloudiness. This means that it becomes very difficult for the user to place the infrared detector inside the confines of his house and expect to be able to detect the on goings outside (Carter, 1989). Many users expected that on placing the detectors on a window, that they could be able to detect intrusion outside the four walls of their houses. Researchers later found out that, it is not possible for infrared light to pass through the glass window panels hence intruders could easily gain access. This means that for the detectors to perform optimally, they must be placed outside, which further increases the chance of risk of vandalism or damage. Light was found to be able to enter into the room where it reached the detector through heating of the glass window; this resulted in the formation of opacity on the infrared radiation that was coming from outside the window. The end result or scenario is that the alarms cannot be activated as there is no reception of infrared radiation from outside the four walls of the house (Bingegeli,2003). A second disadvantage that infrared detectors have is that they are only activated when motion has been detected, they totally disregard that someone or something could be standing on that position or not. This is because motion detectors work on the principal of measuring the differences in the wavelengths of light received so as to ensure that the item or object is not stationery in passive infrared devices however, they do not deal with a person or an object that could be glued to one location (Carter,1989). Application of Infrared Radiation in Security Detectors             Passive infrared detectors are mostly employed for security due to their cost and reliability in sensing intruders. These detectors are able work without the requirement for generation and radiation of its energy (Fay, 2007). Passive infrared sensors first sense the environment in which it is placed by recording and analyzing the temperature of the surrounding. When an object of either lower or higher temperature encroaches into the vicinity, the sensor is able to detect the difference in temperature using differentiation methods.  Manufacturers of infrared motion detectors and other security equipment advise customers on how to place the equipments in order to reduce chances of false alarms. Such instances can occur when bright light is shown to the infrared detector (Fay, 2007). This leads to overload of the chip and hence activates a false alarm. That is why it is advised to place the infrared security detector away from direct sunlight.  Microwave detectors             Microwave detectors exploit microwave energy in their operations as they are able to generate energy of microwave radiation in order to detect movements. The device releases microwave energy that encloses a certain area in which detection of any intrusion acts is to take place. Detection occurs once the microwave beam is reflected back to the receiver as it activates an alarm. Microwave beams are generated by a Gunn diode. Sensors within the device are of two categories, monostatic and bistatic. A monostatic device is normally placed indoors as both the emitter and receiver are housed under one device component. As for bistatic device, the receiver and emitter are separate and hence require a larger are in which to operate in. The area covered by each is different as normally monostatic detectors are able to detect intrusions within 400 feet radius away from the device. With the aid of a beam, an individual is able to use it o fit their surrounding (Travez, 2005).             For a bistatic microwave detector, detection of intruders can be up to 1500 feet away from the device. They are normally used in exterior environments where more area is to be covered. In the beginning people were afraid of the effect of microwave but it has been proven that the devices have few or even no effect on the body unless of instances where the person has been exposed for long durations (Travez, 2005). Microwave Radiation As we continue to discuss about microwave detectors it is imperative for us to mention of how they are generated in the first place. Microwaves radiation fall within the electromagnetic spectrum and have characteristic wavelength ranges from 1mm up to one meter. Their frequency range is between, 0.3 GHz to 300 GHz. Microwaves are prone to effects such as reflection of waves, polarization, wave scattering and microwave diffraction. Microwaves are also prone to absorption from atmospheric elements (McBrewster, 2009). This is particularly true when frequency surpass the 300 gigahertz limit. Microwave radiations are generated by number of sources that utilize the high velocity of the electrons as it travels between both magnetic and electric fields while enclosed in a vacuum. Vacuum tubes devices work on the principle that there are bundles of electrons which crisscross the device at ballistic speeds rather than having a stream like movement (McBrewster, 2009). In our security detector, solid state devices such as Gunn diodes are used in their construction. Operations of A microwave detector             A microwave detector detects intrusion after a time interval has been recorded by the device The location of objects are noted with time using a spread of beams at frequent intervals. Monostatic devices are able to be programmed in order to send beams only at specified and set intervals (Vany,1999). This minimizes the need for the device to be always on hence saving power requirements. The sensors emit interchanging frequencies which are quickly activating and deactivating at very high rates. This is then preceded by the switching off of the receiver on the other end. The time interval between when the beams are sent out is known as Receiver cut off region (Vany,1999). Disadvantages of using a microwave detector             As much as microwave beams can pass through any surface, they unfortunately cannot pass through metals hence it can miss to raise an alarm when intrusion is occurring or will send out a false alarm to the chagrin of the security team (Dakin, 2006). In case where the metals are big enough, it may lead to the shielding of other objects that are behind it and hence they cannot be detected if they are stolen. Its sensitivity may also lead to false alarms as the microwave beams are able to penetrate through walls and discriminate motions that could be normal. Instances of even lighting could trigger a false alarm (Dereniak, 2008). These days there are dual systems that utilize both infrared and microwave detection techniques in order to take advantage of both technologies, where infrared technology is seen as to have its disadvantages; it is rather boosted by the advantages of microwave detectors (Dereniak, 2008). Photo-electric beam detectors             These security detection systems make use of visible light for their operations. They assist in increasing the area of coverage of also infrared detection systems (Travez, 2005). They work by transmitting light which has been modulated. It consists of sensors that are placed to detect difference in the intensity of visible light that could be falling on the detector, if a certain threshold is surpassed then the detector activates an alarm as is records that there is difference between the intensity of light received from other areas and that form the part that is obstructed by the intruder (Travez, 2005). Photo beam detectors are active as they emit light to the surrounding and any change that occurs in this light is detected by any change in reflected light that comes back to the photo beam receiver. CCTV Closed circuit television technology operates using video cameras in the transmission of signals to specific places on a limited number of television sets of monitors. This technology is often used for the surveillance of locations that need close scrutiny (Phillips, 2005). Most areas that are secured through this technology include bank, casinos and even in streets. The city of London is reportedly the most covered city in terms of CCTV surveillance (Phillips, 2005). It has more number of CCTV cameras than the population of the residents. The technology employs the use of visible light and constitutes a camera that is connected to a monitor via a closed connection. Characteristics of visible light             Visible light forms a part of the electromagnetic spectrum and it can be detected by the human eye and several security detectors such as the photo beam detectors. With wavelength properties of approximately 380 Nanometers to about 780 nanometers, visible light is detected in the form of colors under different wavelengths (Phillips, 2005). With blue color at the end of the visible light spectrum on the other extreme end is red which has a higher wavelength. This visible light can be absorbed, reflected, refracted, scattered. Visible light is responsible in causing changes in the retina of our eyes. Visible light is also responsible for affecting physical properties such as temperature and electrical conductivity (Phillips, 2005). Chemical changes have been attributed to visible light and a good example is how visible light is able fade furniture or other materials. It is also used in the field of photography where it turns film negatives to photographs through a series of processes den at the studio. Electrical changes of visible spectrum can be noted through the electrical conductivity of solar cells which are able to generate current when exposed to visible light (Phillips, 2005).  Visible light can also be detected by changes in temperature. With a speed of three hundred thousand kilometers per second vacuum, it can be detected by most photo beam detectors.              Visible light is generated by a number of sources that are emitted after a series of thermal activity on a material. Example of light given out after thermal activity is through actions of the sun and that of incandescent bulb. It has been reported by researchers that only ten percent of energy is converted to light in an incandescent bulb (Phillips, 2005). Advantages of Photo beam detectors             Just as the microwave detectors, photo-beam detectors can be used both indoor and outdoor in averting intruders. Due to their rugged nature, the detectors can be placed in exterior places where it can be exposed to outside environmental elements but this will not hinder their operation. It can be used in the detection of intruders for up to one hundred meters under indoor conditions and up to three hundred meters in exterior conditions (Williams, 2001). They are also very cost effective when compared with the other two solutions that we have discussed above. His is because they are not used for the long range applications and instead are used in the mid range applications such as the protection of a perimeter wall, securing fences, securing warehouses among others. With good alignment of the beams security can be enhanced greatly so as to alert users on incoming intruders. Hey can be placed in a manner that they are hard to notice for any intruder to try and deactivate it (Williams, 2001). Conclusion             We have discussed on the advantages and disadvantages of each of the security devices that use a section of the electromagnetic spectrum. We have also discussed on the types of radiation that they employ for their operations. Each of the above types of detection devices and techniques the devices are connected in a manner that electrical energy is transferred to one of the units which could be an emitter or receiver through a set of connections e.g. wires or they could be wirelessly connected. Most devices employ wired connections in devices that need constant power in order to operate (Williams, 2001). All the signals received by the receiver are transferred to a control unit which controls the operation of the device. Wired system can also vary. The wires could follow a star topology or a bus topology where they are differentiated by how the wire connections are connected to the control unit. Alarm monitoring, the devices are meant to alert the users if there is a degree of oncoming threat. In all the alarms described above, non needs to have a monitoring function as they are able to activate when intrusion has been detected. Monitoring is employed in complex systems that require dedicated users.   Read More