Features of Internal Dual Technology Sensor - Essay Example

Critical Evaluation of an Internal Dual Technology Sensor Name Institution Critical Evaluation of an Internal Dual Technology Sensor Physical movement in a particular area can be detected by motion detection devices installed in specific rooms. Motion detection can be achieved through the change in the course of an object or speed (Dobrzynski, Pericet-Camara, & Floreano, 2012). Physical movement is either detected by mechanical or electronic devices. Mechanical devices are simpler to implement than electronic based but can easily be circumvented. For example, trigger wires can be cut, and the mechanical devices disabled. In electronic appliances, such mechanical intervention is avoided. There are different dual technology types of sensors in the market. The Motion sensor with ultrasonic modulation product by The Watt Stopper combines a PIR sensor with an Ultrasonic transducer (Capel, 1999). One product that uses the dual technology is the DT-355 line voltage that can be mounted on the ceiling. Underlying Principles The firm Watt Stopper is credited with the development of a dual technology sensor technology. The patented model has with time become the ideal in the industry and other businesses have attempted to manufacture their own version of the motion sensor. The dual technology device comprises of two motion sensor components (Drafts, 2001). These are a passive infrared and an ultrasonic sensor (Null, Joyce & Grey, 2013). The ultrasonic transceivers send and receive signals on the same principle as sonar or radar. According to Null, Joyce and Grey (2013), the sensors assess the characteristics of a target object through a sound wave or radio interpretation. Ultrasonic detectors have the ability to detect the presence, volume, speed and classification (Martin, Feng & Wang, 2003). The frequency of the sound emitted is normally too high for the human ear to detect. Basically, the ultrasonic detectors produce a cone-shaped sound and then the echoes are captured and analysed. Transducers are used to turn electrical energy into sound waves and then after receiving the echo turn it back to electric power. According to Ekimov and Sabatier (2006), the ultrasound sensor uses air as a medium, and the sound moves in a wave-like motion. The echo is then evaluated for any movement. The range of the sound waves is usually above 20 kilohertz (Null, Joyce & Grey, 2013). The acoustic sensors can reach the high frequencies of 300 kHz (Martin, Feng & Wang, 2003). The ultrasound sensor detects any unusual shifts in frequency. That is possible because there are predefined frequencies and sounds such that sounds produced by rodents or insects are ignored. In case there is no movement within the detection zone, the pattern of the sound wave produced and reflected back will remain the same, and the alarm will not be triggered. According to Martin, Feng and Wang (2003), the ultrasonic detectors that are based on both the continuous and pulsed wave employ varying data measurement methods. The alarm is only triggered when noticeable shifts are detected such as that produced by human beings. The ultrasonic sensor uses the “Doppler effect” phenomenon as the mode of operation (Hedrick, Hykes & Starchman, 1995). The Doppler Effect can be defined as the apparent dissimilarity between light and sound waves as they leave a source and also the manner they reach an observer. The relative motion of the wave source and of the observer is a significant determinant of the Doppler Effect (Chen, Li, Ho & Wechsler, 2006). The motion sensors that use infrared are the cheapest and relatively reliable in the market. There are two types of infrared based motion detectors- passive and active sensors. For the dual technology motion detector, passive infrared is commonly used with the ultrasonic motion sensors (Cowan, 1991; Fraden, 2004). The passive infrared sensor (PIR) is a companion sensor in the dual technology device. The PIR according to Null, Joyce and Grey (2013) quantify the infrared light glowing from objects within a target area. The primary concept behind the PIR is the use of infrared light to determine the heat of objects that pass in a given area. In essence, PIR sensors identify electromagnetic radiated energy produced by external sources such as the body temperature of individuals. The sensor works by detecting an infrared source such a human when they pass in front of another object with a different temperature such as a wall. A set of sensors makes up the PIR device. These sensors according to Null, Joyce and Grey (2013) are made from synthetic pyroelectric materials that are then mounted on a circuit board that is printed. The circuit board has all the necessary requirements needed to interpret the signals from the sensor chip. The infrared detection zone is made up of both the emitter and receiver which need to be adjusted appropriately to achieve the best balance between the transmitted and reflected infrared energy. There is window typically formed of radiation transparent material that allows the infrared energy to reach the pyroelectric sensor. Focusing elements such as the mirror segments or Fresnel lens can be provided separately from the window. An individual entering a room is detected through their emitted infrared energy that is focused on a mirror segment overlapping a chip section that becomes warmer than it was previously. As an individual move around the room, the hot spot on the sensors chip also moves. The electronics that are connected to the chip then evaluate the moving hot spot in order to perform a control function. According to Null, Joyce and Grey (2013), the motion sensor of the dual technology device modulates or disables the ultrasonic element of sensing through a control circuit. The device has a user interface that allows individuals to adjust the values of the motion detector. The product also comes with a remote control device to input values, as well as, turn the device on and off. The product has a motion sensor for the control of load to protect the ultrasonic-sensitive device (Null, Joyce and Grey, 2013). The ultrasonic sensitive device is any device whose normal operation can be affected by the ultrasound produced by the motion detector. The device also has a means of detecting the radiation emitted in a target area. According to Null, Joyce and Grey (2013), while the user interface has buttons, switches and keys to control the operation of the product, it also has a wireless interface that facilitates the use of remote control. Feedback to the user in the form of kinaesthetic, auditory and visual is also included in the product. The user of the product is at liberty to select the first threshold value that will correspond to the motion sensor’s sensitivity. Having two ultrasonic transceivers allows switching between frequencies. A third sensing technology such as microwave motion sensors can be included and used when the ultrasound function is turned off (Null, Joyce and Grey, 2013). That would be significant so that the functionality of dual technology is maintained. Strengths There are numerous motion detectors in the market, but the ultrasonic detector has numerous advantages. By combining the two established technologies, Watt Stopper produced a product with unmatched performance in occupant detection. The system ensures activation of lights or other systems in case the room is occupied. The dual technology device requires that both technologies are satisfied before the lighting loads are activated. The additional PIR sensor only adds to the strength and efficiency of the instrument. For example, the response time is fast, and no physical contact is ever required. The motion sensor by The Watt Stopper Inc. controls the ultrasonic radiation produced by ultrasonic sensors thereby doing away with any problems that may arise with interference. By the combination of two sensing technology into a single device, the detector is able to reduce instances of false triggering (Null, Joyce & Grey, 2013). It achieves that by minimizing detection probabilities and increasing the vulnerability. According to Martin, Feng & Wang (2003), ultrasonic and passive infrared combination enhances the accuracy of volume and presence detection. Also, the height and distance discrimination are also detected by the dual technology device. By having both the ultrasound and PIR sensor into a single a device, efficiency is enhanced. For motion in a target area to be detected, both types of sensors in the instrument must trip together, and that significantly reduces any chances of false alarms. The heat changes may trigger the PIR sensor but not the ultrasound. Alternatively, objects such as trees may trip the ultrasound but not the PIR, and that enhances the efficiency of the motion detector. While the sensor elements of PIR detect the first level of movement, the ultrasound detects the second level of motion in a particular area. The device is also friendly to the environment. There are no emissions and does not pose any danger to those individuals that come into contact with it. The PIR and ultrasonic sounds employed are not visible or audible for the human detection. In dual technology device, the combination of sensors prevents instances of false alarms and enhances detection. The combination of the ultrasonic and PIR are the most common because they complement each other. PIR fills in where the ultrasound sensor has a weakness while the ultrasonic covers the weaknesses of the PIR. Such a combination is able to ignore small changes such as that of a moving pet. It is an advantage that while the ultrasonic detector can be affected by the inclement weather, the PIR is not affected. The PIR system can be bypassed by individuals wearing heat insulating body suits that have a Styrofoam sheet. Any person wearing such clothing material will pass a PIR device without any detection. Also, by timing the intrusion with the thermal crossover of the instrument, the ultrasonic sensor can be circumvented. The ultrasonic sensors cover such a weakness because they do not rely on individual’s body heat to sense movement. The DT-355 Dual technology device produced by Watt Stopper is mounted on the ceiling, and so instances of interference are minimal. The auto set function of DT-355 selects the optimal settings that are necessary for a given area. Also, the device provides for more comprehensive coverage. The product’s terminal wiring allows individuals quick and easy installation. While a direct line of sight is required for passive infrared sensors in space, ultrasonic sensors cover the entire area, and a line of sight is not necessary. Vulnerabilities While dual technology devices are better than most single technology motion detectors, they also have vulnerabilities. Among the vulnerabilities of the dual technology system includes the fact that the ultrasonic system can affect other wireless devices in the room (Null, Joyce & Grey, 2013). At certain times, the installation options of the ultrasonic based devices can be affected by individual objects such as paper. The dual technology sensor that uses the ultrasonic technology and PIR can be triggered by simultaneous movement of hot air and environmental vibrations that are as a result of moving vehicles. Also, ultrasonic sensors are only useful for shorter range. That limits the area that can be protected by the dual system. Sometimes, the dual system data quality can be affected by the environmental factors such as shadow, light transition and other environmental factors (Martin, Feng & Wang, 2003). Extreme weather conditions are not suitable for the ultrasonic sensors. While the PIR detectors may not be affected, by such weather turbulences, the system may be ineffective. Both ultrasonic and PIR sensors have to operate at optimal levels for the dual technology device to be effective. While the PIR sensors can be circumvented by wearing insulation suits with Styrofoam, ultrasonic sensors can also be bypassed by wearing anechoic suits. The hardware or the software controlling the dual technology motion detector device can be interfered with affecting their efficiency. Concluding Recommendation In conclusion, the dual technology sensor devices are significantly better than single sensor based devices. The weaknesses of one sensor are covered by the other in a dual technology setup. For example, the dual technology device manufactured by The Watt Stopper combines both passive infrared sensors with the ultrasonic detector. Such dual technology devices combining both the ultrasonic and passive infrared sensors are standard in the market because of their efficiency. There are instances where all the triggers can be avoided or triggered to create a false alarm. For example, the movement of hot air together with the environmental vibration such the movement of heavy machinery can trigger a false alarm of such a dual technology motion detector. To prevent instances where the movement of warm air triggers the infrared sensor, the device can be installed with two sensors that can monitor different areas within an area. The alarm will only go off when the two infrared sensors together with the ultrasonic detector trigger the alarm in case an individual walked through the protected area. The product DT-355 can be set by the owner so that only one technology is in use. For efficiency and increased security, it is recommended that the dual functionality is used to prevent circumvention. References Capel, V. (1999). Security systems and intruder alarms. Newnes. Chen, V. C., Li, F., Ho, S. S., & Wechsler, H. (2006). Micro-Doppler effect in radar: phenomenon, model, and simulation study. Aerospace and Electronic Systems, IEEE Transactions on, 42(1), 2-21. Cowan, H. J. (1991). Handbook of architectural technology. New York: Van Nostrand Reinhold. Dobrzynski, M. K., Pericet-Camara, R., & Floreano, D. (2012). Vision Tape—A flexible compound vision sensor for motion detection and proximity estimation. Sensors Journal, IEEE, 12(5), 1131-1139. Drafts, B. (2001). Acoustic wave technology sensors. IEEE Transactions on Microwave Theory and Techniques, 49(4), 795-802. Ekimov, A., & Sabatier, J.M. (2006), “Vibration and sound signatures of human footsteps in buildings,” Journal of Acoustical Society of America, 120(2), pp. 762-768. Fraden, J. (2004). Handbook of modern sensors: physics, designs, and applications. Springer Science & Business Media. Hedrick, W. R., Hykes, D. L., & Starchman, D. E. (1995). Ultrasound physics and instrumentation. St. Louis: Mosby. Martin, P. T., Feng, Y., & Wang, X. (2003). Detector technology evaluation (No. MPC Report No. 03-154). Mountain-Plains Consortium. Null, Jon, Jason Joyce, and Thomas L. Grey. "Motion sensor with ultrasonic modulation." U.S. Patent No. 8,410,922. 2 Apr. 2013. Read More

That is possible because there are predefined frequencies and sounds such that sounds produced by rodents or insects are ignored. In case there is no movement within the detection zone, the pattern of the sound wave produced and reflected back will remain the same, and the alarm will not be triggered. According to Martin, Feng and Wang (2003), the ultrasonic detectors that are based on both the continuous and pulsed wave employ varying data measurement methods. The alarm is only triggered when noticeable shifts are detected such as that produced by human beings.

The ultrasonic sensor uses the “Doppler effect” phenomenon as the mode of operation (Hedrick, Hykes & Starchman, 1995). The Doppler Effect can be defined as the apparent dissimilarity between light and sound waves as they leave a source and also the manner they reach an observer. The relative motion of the wave source and of the observer is a significant determinant of the Doppler Effect (Chen, Li, Ho & Wechsler, 2006). The motion sensors that use infrared are the cheapest and relatively reliable in the market.

There are two types of infrared based motion detectors- passive and active sensors. For the dual technology motion detector, passive infrared is commonly used with the ultrasonic motion sensors (Cowan, 1991; Fraden, 2004). The passive infrared sensor (PIR) is a companion sensor in the dual technology device. The PIR according to Null, Joyce and Grey (2013) quantify the infrared light glowing from objects within a target area. The primary concept behind the PIR is the use of infrared light to determine the heat of objects that pass in a given area.

In essence, PIR sensors identify electromagnetic radiated energy produced by external sources such as the body temperature of individuals. The sensor works by detecting an infrared source such a human when they pass in front of another object with a different temperature such as a wall. A set of sensors makes up the PIR device. These sensors according to Null, Joyce and Grey (2013) are made from synthetic pyroelectric materials that are then mounted on a circuit board that is printed. The circuit board has all the necessary requirements needed to interpret the signals from the sensor chip.

The infrared detection zone is made up of both the emitter and receiver which need to be adjusted appropriately to achieve the best balance between the transmitted and reflected infrared energy. There is window typically formed of radiation transparent material that allows the infrared energy to reach the pyroelectric sensor. Focusing elements such as the mirror segments or Fresnel lens can be provided separately from the window. An individual entering a room is detected through their emitted infrared energy that is focused on a mirror segment overlapping a chip section that becomes warmer than it was previously.

As an individual move around the room, the hot spot on the sensors chip also moves. The electronics that are connected to the chip then evaluate the moving hot spot in order to perform a control function. According to Null, Joyce and Grey (2013), the motion sensor of the dual technology device modulates or disables the ultrasonic element of sensing through a control circuit. The device has a user interface that allows individuals to adjust the values of the motion detector. The product also comes with a remote control device to input values, as well as, turn the device on and off.

The product has a motion sensor for the control of load to protect the ultrasonic-sensitive device (Null, Joyce and Grey, 2013). The ultrasonic sensitive device is any device whose normal operation can be affected by the ultrasound produced by the motion detector. The device also has a means of detecting the radiation emitted in a target area. According to Null, Joyce and Grey (2013), while the user interface has buttons, switches and keys to control the operation of the product, it also has a wireless interface that facilitates the use of remote control.

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