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Design And Construction Of A Motion Sensor

Construction Management/Technology | Electrical Electronics Engineering | Engineering

The design and construction of a motion sensor involve integrating various components to detect movement accurately and reliably. Typically, this involves utilizing passive infrared (PIR) sensors, which detect changes in infrared radiation caused by motion within their field of view. These sensors are combined with supporting circuitry, including amplifiers and filters, to enhance sensitivity and reduce false alarms. Additionally, microcontrollers are employed to process sensor data and trigger appropriate actions, such as activating lights or alarms. The physical construction entails careful positioning of the sensor to maximize coverage while minimizing blind spots, often achieved through adjustable mounting brackets or housings. Calibration and testing are essential steps to ensure optimal performance under different environmental conditions. Overall, the successful design and construction of a motion sensor involve a meticulous integration of hardware and software components to create a robust detection system for various applications, including security systems, automation, and energy management.

ABSTRACT

A motion detector is a device that 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

1.0 INTRODUCTION

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.

1.2 OBJECTIVE OF THE PROJECT

The objective of this work is constructing a security device that alert the occupant of the house or property whenever there is an intruder.

1.3 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.

1.4 PURPOSE OF THE PROJECT

The main purpose of 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.

1.5 ADVANTAGES 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. 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

1.6 LIMITATIONS OF THE PROJECT

Motion sensors have some problem:

it has a limited distance to detect the motion
if a motion sensor for the automatic door is not mounted securely, normal vibration, sign, plants and neon light can trigger the door open.

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.

1.7 PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to a motion sensor. In this chapter, the background, significance, objective limitation and problem of a motion sensor were discussed.

Chapter two is on literature review of a motion sensor. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.

CHAPTER FIVE

5.1 CONCLUSION

The motion sensor switch circuit can automatically turn on a light Before beginning the construction contact your nearest electronics component vendor and procure a readymade box-type Passive Infrared (PIR) Motion Sensor unit.
Such units, packed in a compact enclosure with power input and relay output terminals are widely available. In prototype, an unbranded (Made in China) PIR Motion sensor with the following specifications are used.

Detection Range:10Meter Maximum
Supply Input:12V DC, <500mA
Relay Output :Common(C),Normally Closed(N/C),Normally Opened(N/O)

Now install the PIR module hanging from a 3 metre high mast (to cover 10 metre radius area) and connect its supply and relay terminals to our finished and enclosed circuit, observing right polarity. A 4-core screened cable can be used for this interconnection. Power the circuit from a regulated 12VDC adaptor/solar power box.

Whenever the PIR module detect movement of a live body its relay output toggles and the switching mosfet (T1) in the circuit is switched to on via resistor R1 and related parts. As as result, the EM relay at the output of T1 is activated and the electric sprinkler gets its supply through the relay (RLY1) contacts. This contacts (or spare contacts) can also be used to activate a high-power warning alarm.

5.2 RECOMMENDATION

This project is designed to be used in our homes, engineering laboratory, offices and industries where there is need for an illumination at dark nhours. And should be used and maintain by a qualified personnel.