Efficacy of Detection Sensors - Essay Example

FFIСАСY OF DЕTЕСTIОN SENSORS Name Institution Еffiсасy of Dеtесtiоn Sensors Introduction Most of the modern detectors are using combination of different technologies. Through combination of numerous sensing technologies into a single detector, people could reduce the possibilities of false alarms. The sensors do so through reduction of detection probabilities and increment in vulnerability. In the essays, there will be description of the dual technology sensors, their underlying principles, strengths, and vulnerability. For example, the dual technology sensors integrate different sensors such as passive infrared (PIR) and microwave sensors to come with a single unit (Security Electronics and Networks, 2011). To ensure adequate detection of motions, it is important that both sensors trip together. As a result, there is reduction in the probability of false alarms since the changes in heat and light could trip the PIR but not the microwave or the trees could trigger the microwave but not the PIR (Righini,Tajani & Cutolo, 2009). However, in case an intruder fools either the PIR or the microwave sensors, then the sensors might not detect. In most cases, there is pairing of the PIR technology with another model with an aim of maximizing the efficiency and ensuring reduction in the amount of energy usage. Besides, the PIR tend to draw less energy compared to the microwave detectors. Therefore, several sensors are usually calibrated so that whenever there is tripping of the PIR sensors, there is activation of the microwave sensors. In addition, if the latter picks an intruder, then there is sounding of the alarm. Dual Technology Detectors and Underlying Principles In understand the dual technology detectors and their functionality; it is critical to understand the PIR and microwave principles of performance. The passive infrared (PIR) are sensors that are highly sensitive to skin temperature of a person emitted through the black body radiation within the mid-infrared wavelengths which is in contrast to various objects found within the background at room temperature. From the PIR sensors, there is no emission of the energy hence the name passive infrared. Such features distinguish the sensor from the electric eye, which is mostly not considered a motion detector and works in a manner that a crossing of a person or the vehicle could interrupt a visible or a beam of infrared. On the other hand, the microwave sensors detect motions through the Doppler radar principle, which is the same as the radar speed gun (Lie & Semb, 2009). Usually, there is emission of the microwave radiation continuously with the phases shifting in the reflected microwaves because of the object’s motion from and towards the receiver using the heterodyne signal occurring at low audio frequencies. The combination of the PIR and microwave sensors often provide excellent detection rate and high level of immunity to false alarms and sensors reduction in the call out cost. On the other hand, the occupancy sensors utilize different technologies such as the passive infrared, ultrasonic, and dual technology sensors in a bid to ensure detection of presence or absence of the occupants within a space. Moreover, some of the sensors use acoustic detection. In the occupant sensors, the PIR detect through sensing the difference in the heat emitted from the people and that of the background. However, the ultrasonic sensors detect the presence of people through sending out the ultrasonic sound waves within a space and measuring the returning speed (Madni, 2005). Therefore, the sensors focus on the frequency changes associated with the movement of people. However, the PIR require direct line of sight that occurs between the sensors and the people within the space. Due to such requirement, it is critical that the managers define the coverage of the sensors strictly. The ultrasonic sensors often cover the whole space and do not require the line of sight. Consequently, the ultrasonic sensors have the ability of detecting people behind the obstacles and highly sensitive to the minor motions including the moving hands. The PIR sensors are suitable for the enclosed places, high ceiling areas, space that have high air flow, and areas with direct line of viewing the sight. Besides, the spaces are for masking the unwanted detection within some areas (Patnaik & Li, 2015). Nonetheless, there are issues that could complicate the utilization of such the low levels of motions by the people, obstacles responsible for blocking the view of the sensor, and wrong mounting of the sensors especially on vibrating places or areas with 6-8 feet of air diffusers. Meanwhile, the ultrasonic sensors are majorly suitable for spaces with no possibilities of line of sight including partitioned areas and spaces requiring high levels of sensitivity. There are dual technology sensors that utilize both the PIR and the ultrasonic detectors and only activate the lights only when both the sensors used detect the occupants (ICFICE & Jung, 2013). As a result, such setups play critical roles in the elimination of possibility of false-on problems and require either the sensors to hold the lights on significant to ensure the reduction of false-off problems. For example, the DT-300 Series Dual technology Ceiling Sensors integrates both the benefits associated with the PIR and ultrasonic sensors in detection of the occupancy. Such sensors have flat and unobtrusive appearance, which allow provision of the wider coverage, 360 degrees. Strengths and Vulnerabilities Integration of PIRs in the dual technology sensors has several advantages. The PIR sensors have low false alarm rates when installed within compatible environments, low drain of power, no emission of energy and moving parts, and simple electronics. Moreover, these sensors also have long range of detection, cheaper compared to other sensors, and do not interfere with each other upon installation in groups. More importantly, the sensors are adjustable in terms of the desired lens patterns and sensitivity while in application. PIR are commonly used in the detection of motions since they work through detecting the changes in the coarse within the thermal energy in the view of the sensors. The temperature of the human body differs from that of the background environment; therefore, when a person moves, there are changes within the thermal scene, which the sensor detects (Martinsanz, 2015). Although the PIRs are less expensive compared to others sensors, they suffer from numerous false alarms and vulnerabilities to various detections. Temperature changes could lead to tripping of the sensors. Other factors likely to contribute to the false triggering in the PIR are the headlights, insects, and outdoor air flows. An example of a better sensor is the Xandem TMD which is unaffected by these factors causing false alarm. The major weakness of the PIR sensors is in the detection. They have lenses that deteriorate with time specifically within the dirty environments until the moment when the sensor fails to function completely. Besides, the intruders could as well use the sprays in masking the sensors. Foams, glasses, and insulating materials could allow the intruders pass easily without detection. Moreover, the PIR sensors are unsightly which makes it inappropriate for the high end residential and commercial areas. The dual technology sensors or the hybrid is formed through combination of various motion detectors in a bid to ensure reduction of possibility in the occurrence of false alarms. In most typical environments, people use microwave and PIR through housing them in similar unit. In the dual technology sensors, for the alarm to occur, both the sensors have to detect the motion (Furre & Eiken, 2014). For example, if an HVAC vent turns on, the microwave cannot detect the motion. If the motion takes place on the other side of the wall, the PIR cannot activate. Hence there is no detection of motion. However, there are certain forms of motion, which are problematic. For example, whenever the HVAC turns on, normally there is blowing of air by the nearby fan, which could lead to detection by the microwave, and tripping at the same time. Through attempting to mitigate such false alarms within the dual technology sensors, there is introduction of vulnerabilities. Moreover, the dual technology sensors are as strong as their weakest link. Whenever one blocks the sense using a piece of foam or a glass, the PIR sensor would remain inactivated. Although there is triggering of the microwave sensor, the whole system would not react. Therefore, every time there is a combination of a new sensor within the dual technology sensors, the capabilities of detecting motions and objects are weakened. There are disadvantages associated with utilization of PIR sensors in the dual technology sensors. For example, increments in the ambient temperatures wiuld affect the range and sensitivity of the PIR sensors (Fryxell & Cao, 2007). Moreover, there are high possibilities the intruders could use suits or carry the screens that reflect the heat of the body thus beating the sensing of the PIR sensors. Moreover, both the PIR sensors and microwave sensors have no density or uniformity in the coverage. Moreover, the PIRs would not alarm if there is a failure in the sensing elements which is contrary to the beam sensors. Since random signals of the IRE could cause false alarms, there is a need for frequent maintenance. Besides, it is important to keep clean and ensuring that insects and pests are at bay from lenses and mirrors. Within the dusty environments, the sensors usually draw dusty environments particles through electrostatic, which stick and cloud the vision of the sensor. Using the ultrasonic sensors in the dual technology sensors also presents several benefits and drawbacks the ultrasonic sensors usually sense the movements within the space through transmission of the high frequency sound waves, which are receivable as reflection signals through the Doppler Effect. Usually, an ultrasound sensor floods an area using its coverage pattern and high frequency sound. With such features, any of the moving objects within its coverage are tends to disturb the pattern of the sound wave thus activating the light. The main advantage of the ultrasound sensors is the ability of detecting the sound patterns behind the partitions, solid walls, and any form of obstruction (Hodges, 2009). Nonetheless, such ability could as well contribute to the vulnerability of the sensor since the sensors could detect the objects in the areas not to be included in the coverage including the adjacent hallways and the outside windows. The dual technology sensors that utilize the ultrasonic technology have no ability to distinguish between the human and the non-human motions (Wilson, 2005). Therefore, in most cases, there are problems associated with false detection from the vibrations, air movements, sound systems with ultrasound components, and high sound levels. For example, the ultrasound detectors have the ability of turning on the lights of the building on a regular basis during the night whenever there is kicking of the air conditioning system. Conclusion and Recommendation The essay focused on the analysis of the dual technology sensors, their underlying principles, strengths, and vulnerabilities. The dual technology sensors involve integration of two sensors to improve performance and sensitivity of the system to various objects and occupants of the space of coverage. Imagining of never having to compromise between the performance and false alarm is the benefit associated with dual technology sensors. Most buildings and high-end institutions are choosing the sensor for such reason. In most cases, people prefer using the “winning combination” of the two sensors including microwave and the PIR sensors as they enable the latter sensor to have the ability to distinguish between the real intruders and various environmental conditions that could result in false alarms. Within a dual technology sensor, for the alarm to occur, both the microwave sensor and the PIR sensors have to confirm one another and detect the intruder within the protected areas of coverage. The result of such combination is usually optimum performance and minimal false alarm. However, integration of ultrasound sensors usually presents numerous challenges. To combat such problems, it is important to incorporate the sensitivity adjustment. Although the adjustments play important roles in the minimization of the false tripping lights and alarms, they could also reduce the area of coverage and rely much on the installer to function properly. Although the sensors are usually mounted close to each other, it is important that they operate at distinct frequencies to prevent interference with each other (Czarske, 2001). Moreover, it is important to look for sensors with a dual edge, more than one sensing range, and various possibilities of the discrete zones. Other critical factors to consider are the surge, low voltage protection, the pyro-electric sensing elements, and the LED supported latching. For the PIR sensors, it is important to have temperature compensation, which enables adjustment of sensitivity in line with the increment in the environmental temperatures within the targeted area while considering that some locations could approach and be higher than the temperature of the human body. References Czarske, J. (2001). A miniaturized dual-fibre laser Doppler sensor. Measurement Science and Technology, 12(8), 1191-1198. Fryxell, G. E., & Cao, G. (2007). Environmental applications of nanomaterials: Synthesis, sorbents and sensors. London: Imperial College Press. Furre, A., & Eiken, O. (2014). Dual sensor streamer technology used in Sleipner CO 2 injection monitoring. Geophysical Prospecting, 62(5), 1075-1088. Hodges, L. (2009). Ultrasonic and Passive Infrared Sensor Integration for Dual Technology User Detection Sensors. Retrieved August 16, 2016, from http://www.egr.msu.edu/classes/ece480/capstone/fall09/group05/docs/ece480_dt5_application_note_lhodges.pdf ICFICE, & Jung, H. K. (2013). Future information communication technology and applications: ICFICE 2013. Dordrecht: Springer. Lie, O., & Semb, P. (2009). Characterization of the Eratosthenes Seamount Offshore Cyprus Using Dual-sensor Streamer Technology. 71st EAGE Conference and Exhibition incorporating SPE EUROPEC 2009, 3(2), 122-127. Madni, A. (2005). Full Circle Commercialization of a Dual-Use Micromachined Quartz Rate Sensor Technology. IEEE Sensors, 4(1), 99-105. Martinsanz, G. (2015). Sensors for Fluid Leak Detection. Sensors, 15(2), 3830-3833. Patnaik, S., & Li, X. (2015). Recent development in wireless sensor and ad-hoc networks. New Delhi, India: Springer. Righini, G. C., Tajani, A., & Cutolo, A. (2009). An introduction to optoelectronic sensors. Hackensack, NJ: World Scientific. Security Electronics and Networks. (2011, October 23). Intrusion Sensors: PIRS or Dual Technology | Security Electronics and Networks. Retrieved August 16, 2016, from http://www.securityelectronicsandnetworks.com/articles/2011/10/23/intrusion-sensors-pirs-or-dual-technology Wilson, J. S. (2005). Sensor technology handbook. Amsterdam: Elsevier. Read More