The Design And Construction Of An Automatic Motion Sensor (PDF/DOC)
ABSTRACT
Motion detector detects moving objects, particularly people. A motion detector is often integrated as a component of a system that automatically performs a task or alerts a user of motion in an area. Motion detectors form a vital component of automated lighting control. Its use is to illuminate an area when a person walks by so that he or she can see well. Many people place motion detectors in their backyards or even in their houses so that when they walk through that area, the lights will automatically turn on.
CHAPTER ONE
1.1 INTRODUCTION
The motion detector is not only used as intruder alarm but also used in many applications like home automation system, energy efficiency system, etc. The motion detector will detect the motion of the people or objects and give the appropriate output according to the circuit. In general, motion detector uses different types of sensors like Passive infrared sensor (which will detect the motion of the person using the person body heat), microwave sensor (Microwave sensor will detect the motion of person by measuring the change in frequency from the produced beam), ultrasonic sensor (It produces acoustic signals which will detect the motion of a person) etc. There are some motion detectors which will use different technology and include number of sensors (PIR, microwave sensor, ultrasonic sensor, etc.) to reduce the false triggering and increase the accuracy in motion detection.
1.2 BACKGROUND OF THE PROJECT
The first motion detector was invented in the early 1950s by Samuel Bango, and which was a burglar alarm. He applied the fundamentals of a radar to ultrasonic waves – a frequency to detect fire or thief and that which human beings cannot hear. Samuel motion detector is based on the principle of Doppler Effect. Nowadays, most of the motion detectors work on the principle of Samuel Bango’s detector. IR sensors and microwave sensors can detect motion by the alterations in the frequencies they emit.
Motion detectors are used as security systems in banks, offices and shopping malls, and also as intruder alarm in home. The prevailing motion detectors can stop serious accidents by sensing the persons who are in close proximity to the detector. We can observe motion detectors in shopping malls or stores with automatic doors. The main element in the motion detector circuit is the dual infrared reflective sensor or any other detecting sensor.
An electronic motion detector contains an optical, microwave, or acoustic sensor, and in many cases a transmitter for illumination. However, a passive sensor only senses a signal emitted by the moving object itself. Changes in the optical, microwave, or acoustic field in the device’s proximity are interpreted by the electronics based on one of the technologies listed below. Most inexpensive motion detectors can detect up to distances of at least 15 feet (5 meters). Specialized systems are more expensive but have much longer ranges. Tomographic motion detection systems can cover much larger areas because the radio waves are at frequencies which penetrate most walls and obstructions, and are detected in multiple locations, not just at the location of the transmitter.
Motion detectors have found wide use in domestic and commercial applications. One common application is activation of automatic door openers in businesses and public buildings. Motion sensors are also widely used in lieu of a true occupancy sensor in activating street lights or indoor lights in walkways (such as lobbies and staircases). In such “Smart Lighting” systems, energy is conserved by only powering the lights for the duration of a timer, after which the person has presumably left the area. A motion detector may be among the sensors of a burglar alarm that is used to alert the home owner or security service when it detects the motion of a possible intruder. Such a detector may also trigger a security camera in order to record the possible intrusion.
1.3 OBJECTIVE OF THE PROJECT
The objective of this work is construct a motion sensor that is use is to illuminate an area when a person walks by so that he or she can see well. Many people place motion detectors in their backyards or even in their houses so that when they walk through that area, the lights will automatically turn on.
1.4 SIGNIFICANCE OF THE PROJECT
A motion sensor (or motion detector) is the top dog of your security system, because it is the main device that detects when someone is in your home when they should not be. A motion sensor uses one or multiple technologies to detect movement in an area. If a sensor is tripped, a signal is sent to your security system’s control panel, which connects to your monitoring center, alerting you and the monitoring center to a potential threat in your home.
1.5 PURPOSE OF THE PROJECT
The main purpose of motion sensor is to sense person’s movement then lighten the environment the movement was detected.
Its use is to illuminate an area when a person walks by so that he or she can see well. Many people place motion detectors in their backyards or even in their houses so that when they walk through that area, the lights will automatically turn on.
1.6 APPLICATION OF THE PROJECT
Motion sensors stand guard, ready to react to various situations, such as movement in your living room, windows or doors being opened or closed, or a broken window. Thus, motion sensor lights are very popular and being increased in use. Businesses use them all the time such as for bathrooms, when a person walks in, the lights turn on. Or many times they are used in grocery stores for when you pass through an aisle or open up a refrigerator door in the freezer aisles. The applications are numerous.
Motion sensors can:
- Alert you in the event that your teen breaks curfew
- Trigger a doorbell when someone approaches the front door
- Alert you when kids enter restricted areas in the home, like the basement, workout room, or medicine cabinet
- Save energy by using motion sensor lighting in unoccupied spaces
- Notify you if pets enter areas where they’re not supposed to be
1.7 LIMITATIONS OF THE PROJECT
Motion sensors have some problem:
1 it has a limited distance to detect the motion
2 if a motion sensor for the automatic door is not mounted securely, normal vibration, sign, plants and neon light can trigger the door open.
3 It cannot detect the small objects such as insects or raindrop.
- Things may trigger the motion detector that you don’t want to. An outside detector mounted too close to a light that stays on at night, will be triggered continuously by bugs.
- The set shutoff time of the motion sensor may be too short (maybe only 30 seconds). For outside lights with a motion detector, if you want more “on time”, it’s best to buy a model with an adjustable shutoff time.
- The reliability of a motion sensor may also be affected by rapid environmental changes and direct sunlight. Also, things like a fireplace, and direct wind from an air conditioner or heater. This is because a PIR sensor actually detects changes in infrared energy – specifically, the “heat energy” emitted by normal human skin temperature.
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 REVIEW OF PIR SENSORS AND ITS APPLICATION
A passive infrared sensor is often used in motion detectors. A motion sensor (or motion detector) is the linchpin of your security system, because it’s the main device that detects when someone is in your home when they shouldn’t be. A motion sensor uses one or multiple technologies to detect movement in an area. If a sensor is tripped, a signal is sent to your security system’s control panel, which connects to your monitoring center, alerting you and the monitoring center to a potential threat in your home.
The following guide will answer all your questions about motion sensors: the different types, proper placement, and how to use them.
2.2 THE ROLE OF SENSORS IN YOUR HOME SECURITY
The main purpose of ir sensor used in motion detection is to sense an intruder and send an alert to your control panel, which alerts your monitoring center. Sensors work when you are not home, or when you tell the system you are not there. Some security systems can be programmed to record events via a security camera when motion is detected.
sensors stand guard, ready to react to various situations, such as movement in your living room, windows or doors being opened or closed, or a broken window when used as motion detector. Motion sensors can:
- Alert you in the event that your teen breaks curfew
- Trigger a doorbell when someone approaches the front door
- Alert you when kids enter restricted areas in the home, like the basement, workout room, or medicine cabinet
- Save energy by using motion sensor lighting in unoccupied spaces
- Notify you if pets enter areas where they’re not supposed to be
Passive and Active Motion Sensors
There are two types of motion sensors: passive sensors and active sensors. Each uses different technology to detect motion in the designated area. Passive sensors do not emit energy, but read changes in energy in the surrounding area. Active sensors emit one of three kinds of energy to identify motion in the surrounding area: infrared light, microwave radiation, or sound waves.
2.3 TYPES OF MOTION SENSORS
Passive Infrared (PIR):
Detects body heat (infrared energy). Passive infrared sensors are the most widely used motion in home security systems. When your system is armed, your motion sensors are activated. Once the sensor warms up, it can detect heat and movement in the surrounding areas, creating a protective “grid.” If a moving object blocks too many grid zones and the infrared energy levels change rapidly, the sensors are tripped.
Mirco Wave (MW):
Sends out microwave pulses and measures the reflection off a moving object. They cover a larger area than infrared sensors, but they are vulnerable to electrical interference and are more expensive.
Dual Technology Motion Sensors:
Motion sensors can have combined features in an attempt to reduce false alarms. For example, a passive infrared (PIR) sensor could be combined with a microwave sensor. Since each operates in different areas of the spectrum, and one is passive and one is active, Dual Technology motion sensors are not as likely as other types to cause false alarms, because in order for the alarm to be triggered, both sensors have to be tripped. However, this does not mean that they never cause false alarms.
Area Reflective Type:
Emits infrared rays from an LED. Using the reflection of those rays, the sensor measures the distance to the person or object and detects if the object is within the designated area.
Ultrasonic:
Sends out pulses of ultrasonic waves and measures the reflection off a moving object.
Vibration:
Detects vibration. These can be purchased or easily made at home. A homemade vibration sensor uses a small mass on a lever, which is activated by a switch to an alarm when it vibrates. Homemade motion sensors can work, but they can also be unreliable.
2.4 OTHER MOTION SENSOR FEATURES
Wireless Motion Sensors:
Today, most motion sensors are wireless. Wireless sensors are very easy to set up. They do not require drilling, and they communicate with the other security system components wireless.
Contact Motion Sensors (door/window):
Most contact motion sensors are passive infrared sensors. They trigger an alarm if the protected door or window is opened while the system is armed.
Pet Immune Motion Sensors:
A passive infrared sensor can be set up to ignore animals up to a certain weight. A dual technology motion sensor is more resistant to false alarms caused by animals because it requires two sensors to be triggered in a manner determined by the manufacturer. They can be set up to ignore a large animal or multiple small animals without setting off a false alarm. Some sensors have a sensitivity level that can be adjusted for families with very active animals.
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