Week 7 - Movement Sensors, Group E

The general definition of the movement or motion sensor is a device that detects moving objects, mainly people, then perform a task, send a signal, or alarm a user of a motion on that area. There are different types of motion detections methods that used in motion sensors. Some of these popular methodes are:

·      Passive infrared (PIR): these detectors measure the change in the energy of the surrounding area. Their limitations are that they’re really sensitive to the environmental changes as hot or cold airflow, which might cause sending a false alarm to the user.

·      Active infrared (AIR): these detectors works by an IR emitter sends a beam of an IR, which will be received by an IR receiver; so, when the IR beam interrupted, the motion is detected. Typical uses of AIR are in automatic trash bin, water tabs, and automatic doors.  Their limitations are that they can be easily seen; therefore, using it in a security system is not good idea.

·      Ultrasonic: it has the same process as the AIR but instead of an IR beam, it’s an ultrasonic.

·      Optic-based: it’s basically a camera takes or records several frames and detects any different between these frames. When there is a difference, a motion is detected.

The most common types used are the AIR and PIR. The main difference between these two types are that the AIR is sending out signals and search for motion on the surrounding area while the PIR is reacting to a signal that reaches to the detector.

The motion sensors used outdoor and indoor in many of nowadays building. Motion sensors often used in indoor space to control lights, while they are used often in outdoor spaces as an alarm system. When using motion sensors in outdoor area, it’s important to select the one are rated for outdoor usage since the indoor models do not have the enough protection to prevent the electronics on the circuit board get damaged by the moisture or heat effects.

Using motion sensors is a great way to save energy and costs. As an example, by using motion sensors in controlling lights will turn off the lights when there is no motions so both energy and electric cost would be reduced.  

Sources

"Using Motion Sensors Outdoor." Smarthome. N.p., n.d. Web. 18 Feb. 2014. <http://www.smarthome.com/sh-solutions-use-motion-sensors-outdoors.html>.

"Different Types of Motion Sensors." Different Types of Motion Sensors. Sand Hill Engineering Inc, Jan. 2007. Web. 18 Feb. 2014. <http://www.shed.com/tutor/sensors2.html>.

http://media.digikey.com/pdf/Data%20Sheets/Panasonic%20Electric%20Works%20PDFs/AMN%20Design%20Manual.pdf