Design And Construction of A Sensor Operated Automatic Door System

ABSTRACT

The project is titled design and construction of a sensor operated automatic door system. Opening and closing of doors is always a tedious job, especially in places like shopping malls, hotels and theatres where a person is always required to open the door for visitors.

This project proposes a system of automatic opening and closing of door by using sensors. The PIR sensor transmitter emit infrared radiation  from a considerable distance and sends it to the receiver, commanding the receiver to either open the gate or to close it. This sensing signal is fed to a controller to operate a door motor through motor driver IC.

The sensor sends a logical command to open the door. The door automatically closes with a fixed time delay.

CHAPTER ONE

1.1                                                        INTRODUCTION

An automatic opening and closing of door sensor involves open and closing a door using sensor: The most common single-technology sensor operated door uses passive infrared (PIR) energy to recognize the movement of heat in a protected space, and the sensor compose of the transmitter and the receiver.

This project proposes a system of automatic opening and closing of door by pressing a remote when we want the door to be close  and vice-versa. This is achieved with help of a PIR (Passive Infrared) sensor. When the remote is pressed the sensor emits infrared energy which is been received by the receiver from a considerable distance. This sensing signal is fed to a controller to operate a door motor through motor driver IC.

When the remote is pressed, it sends a logical command to open or close the door. The door automatically closes with a fixed time delay. If there is no further movement within the PIR operating range. Interrupt signals are used through limit switches to avoid locked rotor condition of the motor.

1.2                                               OBJECTIVE OF THE STUDY

The main objective of a design and construction of a sensor operated automatic door system, that is, to open and closing a door using sensor.

1.3                                         SIGNIFICANCE OF THE PROJECT

Automatic doors operate with the help of sensors. Sensors do exactly what they sound like they’d do: they sense things. There are many different types of sensors that can sense different types of things, such as sound, light, weight, and motion.

For example, some automatic doors operate when they’re triggered by sensors that sense weight. These weight sensors might be disguised in a rubber mat in front of the door. When you step on the mat, the sensors send a signal to the automatic doors that tells them to open.

Other automatic doors operate on optic or motion sensors. These sensors might be mounted above a set of automatic doors or built on the top or the sides of the frame of the automatic doors.

When these optic or motion sensors sense motion nearby, they trigger the automatic doors to open and then close. This is why, when you approach a set of automatic doors, they will open as soon as you get close enough to activate the sensors.

Automatic doors have many useful purposes, which is why you can find them in many different types of locations. From supermarkets to airports and many types of large buildings, automatic doors make it easier for people to get into and out of buildings. They are especially helpful for people who are handicapped.

Similar to revolving doors, automatic doors also help to save energy, since they limit the amount of time that doors are open to only those times people are entering or exiting a building. And if you’ve ever shopped until your hands are full of bags, you know how handy automatic doors can be when it’s time to head to the car!

1.4                                                 USES FOR PIR SENSORS

PIR sensors aren’t just used for home security. In industrial fields, they are used on assembly lines to keep track of the number of products and to shut down dangerous equipment if a person gets too close.

Here are a few other ways PIR sensors are used:

• To open and close automatic Doors
• To turn on and off automatic water faucets and toilets
• To turn on lights when a person enters a room
• To control ATM displays
• At automatic ticket gates
• For some parking meters

PIR sensors aren’t just an additional feature of a security system—they are essential. Without sensors, there wouldn’t be a way to detect intruders.

 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.

MircoWave (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 wirelessly.

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.

Video Motion Sensors:

Combines video cameras with advanced signal processing. Some recordable motion sensors start recording when they sense motion. Cameras controlled by motion sensors can save you memory storage by not recording hundreds of hours of useless footage—they only capture the important stuff.

2.5                     REVIEW OF DIFFERENT AUTOMATIC DOOR SENSORS

Today, there are mainly three different sensor technologies used in the market.

Active Infrared

Functional Principles: An Active Infrared Detector always consists of one transmitter and at least two receiver chips with high-quality optical systems. The scanning range is set by means of a mechanical micro-speed unit by changing the angle between the transmitter and receiver. This optical procedure is called triangulation or optical differential measurement.

Active Infrared Detectors are static—they only detect persons and objects if they break the beam. The detection area consists of spots, and depends to a large extent, on the optical center-to- center distances of the transmitter and receiver lenses. Several beams can be combined in a modular system to form a larger area.

Background suppression presence detectors are used on moving parts like a swing door or revolving door. This system does not require a background like a wall or floor.

Background analysis requires a signal from the background in order to switch the output.

• The sensor is installed and requires a background (floor/wall). The output is deactivated.
• The desired scanning range is set mechanically within the predefined possible distances.
• Each object within the set scanning range is detected statically.

Passive Infrared

Functional Principles: Passive Infrared Sensors function in a similar way to infrared cameras used to detect heat loss from buildings. The infrared-sensitive sensor forms a heat image of the defined area to be monitored. After an initial set-up time of approximately 20 seconds, the measured infrared image is saved. The sensor switches if the heat image changes as a result of movement. Two conditions must be fulfilled here:

1. There must be a temperature difference of +/- 1.8 F between the object to be detected and the background.
2. The object to be detected must move at a rate of at least 4 inches per second.

The system is ideal for detecting people only if— There is always a difference of at least 1.8 F between the surface temperature of a clothed person and the surrounding environment. For reasons of a physical nature, this technology should only be used to detect living beings as it’s not always possible to guarantee that the difference in temperature between items such as shopping carts or vehicles, and that of the surrounding environment will be great enough.

Microwave

Functional Principles: Microwaves are electromagnetic waves such as those emitted by a radio transmitter but with a much higher frequency (1GHz). Thanks to the variable antenna, the microwaves emitted by the transmitter can be directed without any difficulty and are reflected back to the receiver via the floor, walls and other surfaces.

If there is no movement in the monitored zone, the transmitter and receiver frequency remain the same—the zone is clear. People and objects, however, activate the motion detector as they move through the monitored zone. The emitted and received frequencies are no longer identical. The difference between the frequencies is evaluated and transferred via relay or electronic contacts in the form of a switching pulse. The microwave power used is perfectly safe for humans and animals.

How to Combat Interference

In addition to known influencing factors such as rain, snow, fluorescent lamps and fundamental vibrations of door drives, there has also been a steady increase in parasitic interference caused by items such as mobile phones, radio and X-ray equipment—commonly called electrosmog. Optimized circuits and other suppression components provide extensive protection.

Today, more special features are available. Environmental awareness, and energy and cost-savings are not just empty promises anymore. Here are some of the features available:

• Distinguishing between movement toward and away from the detector. A few known models can even distinguish between cross-traffic and approaching traffic.
• Separation between people and vehicles, which would allow a door to open differently for a vehicle versus a person.
• Setting up a sensor with an easy-to-use remote control is standard today. Two models are known in the market: Unidirectional, where you read the setting by counting blinking LEDs on the sensor; or a bidirectional remote, which allows you to read out the settings and visually shows them on the remote.

3.5                     DIFFERENT SENSORS FOR DIFFERENT APPLICATIONS

The most common doors are sliding, swing and revolving doors. There are low-cost sensors, which basically can only fulfill one major duty—detection or not. But there are also sophisticated sensors available which not only open a door, but can also be used for special applications. For example: a hotel entrance door that’s activated every time a car pulls up. This action can now be eliminated. Today, there are sensors that will ignore cross-traffic, only activating the doors when a person walks toward it. Many hotel managers will be glad to hear that.

Active infrared sensors are not only being used to activate a door, but also to detect presence so a door doesn’t close while a person or object is still in the door’s path.?

Swing doors are by far the most common automated pedestrian doors in North America. Most swing doors are activated by a sensor and secured by another. We differentiate between a header-mounted sensor and a door-mounted sensor. Header-mounted sensors are often used for activation, but there are also header-mounted sensors available for safety. Door-mounted sensors are basically for presence-detection to assure the door is not closing on a person in the path.

Sliding doors are the second-most used doors in the industry. Generally, the swing door is activated on both sides, and also has some presence features, either by beams in the threshold or a presence sensor. There are also combined sensors available on the market where the activation and presence is included in one unit.

Revolving doors are common, but seldom are they fully automated. A fully automated revolving door requires a set of activation and safety sensors. Activation sensors start the movement of the door; presence sensors assure no one is being hit by a moving door. Often, there is a single beam sensor on the closing edge, a presence detector on the moving leaf and, in addition, there are mostly electrical sensing edges and safety mats used.

Active infrared sensors

The principle behind infrared automatic door sensors is the transmission and receiving of infrared light. An element known as a light emitting diode (LED) transmits active infrared light, which is reflected on the floor and received by an optical receiver known as a photo diode (PD). As long as there is no movement or object in the path of the light beam, the light pattern is static and the sensor remains in stand-by.

When a person or object crosses the beam, the reflection of the light is distorted. This is registered by the PD, which gives off an impulse for opening the door.

Sensors differ in the number of rows of active infrared spots. These spots are collectively referred to as the detection area.

Because objects cause a distortion in the reflected light pattern, active infrared sensors also react to shopping carts and other moving objects.

Initially, the sensor is set according to the situation at the location. Any time there is a change in this standard state, it is recognized. The sensor is also able to continue to recognize this situation.

Active infrared sensors are excellent as a safeguard at the door opening because of their ability to continue recognizing changes that occur in the detection area. Some sensors may incorporate a second row of detection areas to create a safety area in addition to the standard first row. The safety area prevents the door from closing prematurely.

As long as there is a person or object in the detection area, the sensor remains active, preventing the door from closing. This ensures an additional layer of safety over other types of sensors as the door does not close while someone is in the detection area. There is no theoretical limit to the maximum time that can be set for a sensor, though this does depend on the type of sensor. A safety area is sometimes employed for when the door is open for a long period of time.

Active infrared door sensors are generally immune to the effects of external factors such as rain, snow and falling leaves. Although the sensor registers this type of movement, intelligent software is employed to screen such factors out.

Passive infrared sensors

A passive infrared door sensor works on the basis of ambient temperature. It measures the temperature and emits a pulse as soon as there is a change, recognized as 1° C or about 1.8° F when a person is walking at 1.2 meters (4 feet) per second. A passive infrared sensor therefore reacts only to objects that radiate a particular temperature, such as humans or animals. Baby carriages, shopping carts and wheelchairs are not detected, though the person behind or in them are. In practice, a passive infrared sensor is mainly intended for use in a conditioned environment, such as inside buildings.

Microwave sensors

A door sensor using a microwave technique works according to a completely different principle than one based on infrared rays. With microwaves, an antenna constantly emits a “balloon” at a specific frequency (24.125 GHz). As soon as there is a change in the volume of the balloon, the sensor reacts. This may be triggered by either an object or a person. A microwave sensor thus reacts to baby carriages, shopping carts and wheelchairs as well as people.

A major difference from other sensor types is that the microwave sensor becomes accustomed to anything in its detection area if it remains. The microwave sensor therefore stops emitting the pulse for opening the door if a person or object stays in the area.

Most microwave sensors are available in two types, unidirectional or bi-directional. If a faster closing door is required, a unidirectional microwave type is recommended. Such sensors react only to exiting traffic.

Some microwave sensors also incorporate both functionalities. The desired function can be switched according to need.

Safety beams

Safety beams also use an active infrared technique. Safety beams are fitted in the door opening, serving to prevent the doors from closing prematurely. The transmitter and receiver are installed opposite each other. As long as the beam is interrupted between the transmitter and receiver, the door is prevented from closing.

A miniature safety beam guarantees stable and dependable operation, even in bad circumstances. The innovative design makes installation very simple and fits all door profiles.

Insensitive to sunlight

The safety beam is insensitive to horizontal, incident light, even sunlight. The infrared beam is emitted by a light emitting diode (LED) installed in the transmitter head and detected by a photo diode (PD) in the receiver head. The wavelength of the infrared beam is about 0.9 mm (near infrared).

Pulsating code

The beam type used in the safety beam photo-electric detector is sensitive to a variety of light such as sunlight, car headlights and lightning flashes. A pulsating code is therefore used in the infrared beam to filter out these light sources from the emitted safety beam. The safety beam receiver is constructed so that it reacts only to interruptions in this pulsating infrared beam. Other light sources therefore do not affect the receiver.

Strong light filter system

Conventionally, safety beams are affected by directly incident sunlight in the receiver, resulting in non-activation. OPTEX has incorporated a light filter in the safety beam to ensure faultless operation even in strong sunlight.