This week was all about sensors and it was extremely interesting to see how many different sensors are available and used in everyday applications. This week I focused on movement sensors and found that the most used type of movement sensor is called a Passive Infrared Sensor, PIR. This sensor uses heat to detect movement within a given area. This sensor is used in automatic lighting schemes, burglar alarm systems, automatic welcome greetings and even motion detecting remote cameras (see video below). These sensors usually have a range of approximately 20 feet but will practically never wear out, are extremely reliable, incredibly cheap and simple to use.
I thought it was incredibly important to note, especially with the talk of data overload in recent classes the number of readings that single sensors are able to take. Both Junwah Ng , and Xiang Li talked about different senosors, humidity and pressure respectively, but both mentioned the number of measurements each of these sensors can take. Even though the PIR sensor is simple I am sure that there are a number of movement sensors that provide an abundance of measurements that can be recorded to help in disciplines such as traffic studies, population tracking, mass transit security and monitoring and many more.
References:
http://www.gadgetshack.com/motionsensor.html
http://www.ladyada.net/learn/sensors/pir.html
http://www.instructables.com/id/PIR-Motion-Sensor-Tutorial/
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Showing posts with label Movement Sensors. Show all posts
Showing posts with label Movement Sensors. Show all posts
Tuesday, February 19, 2013
Movement Sensors
Prior to this week’s assigned
research, I thought I understood the basic concept of movement sensors and how
and why they were commonly used, yet as I continued doing my research I became
more aware of the importance and dependability that other systems have over
this system. Movement sensors detect
changes in positions of a person or object relative to its environment or the
other way around. There are six types of
motion detectors that are commonly used including: infrared, optics, radio
frequency energy, sound, vibration, and magnetism.
The types of movement sensor methods
are mechanical and electronic methods.
Most people are unaware of the mechanical movement sensors around us,
yet unknowingly we use these daily and vastly.
From the moment we wake up we use movement sensors such as the moment we
turn our alarm clock off, when dialing
the heating time in our microwaves, typing in our computer keyboards or even
the simple motion of flicking the light switch.
Electronic detection sensors are ones that detect optical or acoustical
motion. Examples of when we encounter these
sensors include the ones that activate lighting, activate a camera to turn on, or
even trigger an alarm.
Because of the wide range of
functions of movement sensors, these are the most used type of sensors. Other types of sensors are dependent and rely
on these sensors in order to activate or deactivate. For pressure sensors, like my classmate C.
Meraz explained, a piezoelectric pressure transducer uses crystal to convert motion into an electrical output since “these
sensors are also highly susceptible to shock and vibration”. With
flow sensors, like Brian V says in his blog post, record measurements within a
flow meter of flow of fluids or gases.
These measurements are found by observing the movement of such fluids or gases.
Matthew Tedesco also explains that “aside from mechanical flow meters,
fluid velocity and flow can be measured using optic sensors”. As explained before, optic motion sensors
fall under the movement sensors category.
In conclusion, we can encounter movement sensors in our everyday life and
they also play important roles in other practices.
Sources:
Monday, February 18, 2013
Week 7: Movement Sensors
When analyzing movement sensors, they can be broken down into two main types of movement sensors: active motion detectors and passive motion detectors. Active movement sensors utilize sensors that emit a type of signal that is then reflected back and detected. Passive movement sensors do not actually emit a signal like active sensors, but instead detect the signals being emitted by the objects in their field of view and have a predetermined baseline reading for the surrounding area.
Active movement sensors are mainly used in places where a rapid response from a change in detection is needed (ultrasonic or microwave). For example, a motion sensor for a car garage uses an active ultrasonic radar-like sensor that emits sound waves. When the sound waves are emitted, the sensor detects the pattern or the time it takes for those waves to bounce off of its surroundings and return back to the sensor. When an object is approaching the garage door or entering the space under the garage door while it is closing, the sound waves are emitted and bounce off of the object crossing the path of the sensor causing the return time to be faster. This is then computed by the sensing system and tells the garage door mechanism to open so as to allow a car to enter or to prevent the door from closing on something or someone.
Passive movement sensors detect a change in their surroundings by reading the energy of their surroundings. These types of sensors come in various forms, some of the most common being infrared or photo sensors. These sensors detect and measure the energy that is being produced by the objects in their line of sight and are commonly used in home security systems or businesses to warn them of someone entering the facilities. Bodies that generate heat, be they humans or animals, also generate infrared energy (for humans usually ranging between 9 and 10 micrometers). With this range in mind, infrared sensors are programmed to detect emissions within the range of 8 and 12 micrometers with the use of a photo detector. This sensor measures the light being transmitted to it, converts it into an electrical current that is sent to the sensor’s processing core. “The alarm is triggered when the photo detector detects large or fast variations in the distribution of the emitted infrared energy.” (1). This form of detection allows for the movement sensor to ignore slight variations in heat that occur over the length of the day, such as the slow change in temperature of objects in the sensor’s field of view as their temperatures cool down over night.
These sensors are very inexpensive and can offer a very secured environment when combined to cover all entry points of the desired area.
I found it interesting in my classmate Matthew Tedesco's post (http://ae-510-ay12-13.blogspot.com/2013/02/flow-measurement-of-fluids-including.html) how he explained the various applications a specific type of sensor may have. Movement sensors aren't limited to only sensing movement, but as Matthew described, optic sensors (which are a type of movement sensor) can also be used to measure mechanical flow, fluid velocity and flow.
Sources:
(1) http://www.ehow.com/how-does_4596955_motion-sensor-work.html
(2) http://home.howstuffworks.com/home-improvement/household-safety/security/burglar-alarm2.htm
(3) http://home.howstuffworks.com/home-improvement/household-safety/security/question238.htm
Active movement sensors are mainly used in places where a rapid response from a change in detection is needed (ultrasonic or microwave). For example, a motion sensor for a car garage uses an active ultrasonic radar-like sensor that emits sound waves. When the sound waves are emitted, the sensor detects the pattern or the time it takes for those waves to bounce off of its surroundings and return back to the sensor. When an object is approaching the garage door or entering the space under the garage door while it is closing, the sound waves are emitted and bounce off of the object crossing the path of the sensor causing the return time to be faster. This is then computed by the sensing system and tells the garage door mechanism to open so as to allow a car to enter or to prevent the door from closing on something or someone.
Passive movement sensors detect a change in their surroundings by reading the energy of their surroundings. These types of sensors come in various forms, some of the most common being infrared or photo sensors. These sensors detect and measure the energy that is being produced by the objects in their line of sight and are commonly used in home security systems or businesses to warn them of someone entering the facilities. Bodies that generate heat, be they humans or animals, also generate infrared energy (for humans usually ranging between 9 and 10 micrometers). With this range in mind, infrared sensors are programmed to detect emissions within the range of 8 and 12 micrometers with the use of a photo detector. This sensor measures the light being transmitted to it, converts it into an electrical current that is sent to the sensor’s processing core. “The alarm is triggered when the photo detector detects large or fast variations in the distribution of the emitted infrared energy.” (1). This form of detection allows for the movement sensor to ignore slight variations in heat that occur over the length of the day, such as the slow change in temperature of objects in the sensor’s field of view as their temperatures cool down over night.
These sensors are very inexpensive and can offer a very secured environment when combined to cover all entry points of the desired area.
I found it interesting in my classmate Matthew Tedesco's post (http://ae-510-ay12-13.blogspot.com/2013/02/flow-measurement-of-fluids-including.html) how he explained the various applications a specific type of sensor may have. Movement sensors aren't limited to only sensing movement, but as Matthew described, optic sensors (which are a type of movement sensor) can also be used to measure mechanical flow, fluid velocity and flow.
Sources:
(1) http://www.ehow.com/how-does_4596955_motion-sensor-work.html
(2) http://home.howstuffworks.com/home-improvement/household-safety/security/burglar-alarm2.htm
(3) http://home.howstuffworks.com/home-improvement/household-safety/security/question238.htm
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