Design And Construction of Automated Barrier For Car Park Gates

International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, Volume 2, Issue 11, November 2012) Des...
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International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, Volume 2, Issue 11, November 2012)

Design And Construction of Automated Barrier For Car Park Gates Amusa K. A.1, Nuga O. O.2, Adetomi A. A.3 1,2,3

Federal university of Agriculture, Abeokuta, Nigeria

I. INTRODUCTION

It is against these considerations that this work is embarked upon to design and construct a prototype of an automated barrier system to a car park in a bid to find ways of improving service delivery and better use of human resources. This paper comprises of five sections. In section two, a review of related literatures with respect to gate system and access control is presented. Design considerations and specifications are discussed in section three. In section four, construction procedure and test results are presented. Finally, conclusion is presented in section five.

Access to a driveway, garage or car park may be restricted for the purpose of toll or ticketing collection or when maintenance work is being carried out. In some situation, it may be introduced in a driveway to check excesses of road users in terms of speed. To ensure strict compliance, security of the parked cars, tolls may be required of the users of a car park for using the parking lot. Subsequently, a user will be issued a tally or slip or any other form of identification which serves dual purposes. First it shows that the holder has satisfied the requirement of gaining access legally into the park; and secondly the holder must produce the tally to exit the park to check theft. Commercial areas, higher schools of learning, teaching hospitals are usually characterized by beehive of activities. Consequently, the car parks in these areas are heavily patronized. Thus it is pertinent for both security and economic reasons to have proper control of access to these car parks. The simplest of such access control is usually done by using a tied rope or chain suspended across the entrances. This will be released or not depending on whether the intending car park user is granted access or not. Suppose an establishment has about five car park designated areas. If each of these parks is manned by two officials, a total of ten will be required for manning of car parks alone. Suppose we have an automated system where it will only require at most an official to man a car park at a time, then considerable resources will be conserved. Consequently, these resources can be deployed elsewhere and thereby lead to better utilization of available resources.

A gate operator can be described as any mechanical device employed to control access i.e. used to close and open a gate, such as one at the entrance of a car park or end of driveways [1]. There exist three main categories of electric gate operators. These are: worm (screw) driven openers; arm openers; underground loop openers. Automatic and electric gate openers are designed for both swinging and sliding gates. Gates openers can be either a mechanical gate (this kind of gate opener draws power from the mains to open a driveway gate or a gate to a car park) or hydraulic gate (this is used to automatically open an access to an enclosed area; hydraulic gates use hydraulic fluids to operate their motion). Gates are of different types, these include Swing gate (which can employed a swing arm operator; a ram arm operator or underground operator for its operation), Slide gate (this type of gate is commonly installed in the closed position; sliding gates are often large, heavy and therefore more hazardous than swing gates), Barriers (these are automatic gates consisting of a breakaway gate arm, motor assembly and housing usually installed at the departure end of a toll island or a car park), Overhead (this type of gate system is usually installed to control access to a driveway or an enclosed area by limiting the size of allowed vehicles; such gates usually involved a permanent bar fixed across the entrance or at specific position in the driveway raised to appropriate height to allow or disallow vehicles passage accordingly).

Abstract - Access to a driveway, garage or car park may be restricted for the purpose of toll or ticketing collection or when maintenance work is being carried out. In some situation, it may be introduced in a driveway to check excesses of road users in terms of speed. Two approaches for the control of the barrier to a car park are explored and construction of prototype is carried out, in other to demonstrate workability and suitability of the design. Keywords - Automated, barrier, gate operator, car park

II. BACKGROUND THEORY

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International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, Volume 2, Issue 11, November 2012) Different methods are available for control of gate system depending on individual choice and applications [1]. Common control devices for automatic gates include: Telephone entry; Keypad access; Transmitters access; Radio Frequency IDentification (RFID); Timer method; Emergency access; Card reader access; Use of intercom; In-door push buttons; and Biometric methods.

The DC motor arms were interfaced with the microcontroller via an integrated circuit ULN2003A since direct connection to the microcontroller is not possible in the first design approach while in the second case; there is no need of using such IC to interface with the relay gang. Aluminum bars are chosen to ensure light load for the motors and have to be split into two equal halves for span of each of the entrances to avoid deflection, twisting or instability of the bar that may result when a single full length is used.

III. DESIGN CONSIDERATIONS AND SPECIFICATIONS Two approaches were explored to achieve the desire objective design, construction and deployment of the barrier. In the first approach, the design involved use of programmable integrated circuit (PIC) for control; magnetic card encoder/reader and infra-red sensors for gaining access and another IC to interface motor arms to PIC. In the second approach, indoor push buttons and gang of relay were used in the design to realize the design objective. For the two approaches, the following were common components employed in the design and construction of the prototype of an automated barrier system: Power supply unit, 4 - 12V DC motors extracted from wiper arms of Mercedes Benz car; and 4 - 500mm by 5mm by 2.5mm rectangular aluminum bar.

The Design involving PIC 18F452: The barrier system employed magnetic card reader/encoder to control access at the IN- gate where ticketing is required. When a car approaches the IN-gate, an encoded magnetic card is swiped across the magnetic card reader slot. The magnetic card reader is connected via UART to the microcontroller, which is at the heart of the control logic. The microcontroller then processed the data sent by the magnetic card reader. If the data is found valid, the gate opens. There is an infra-red sensor arrangement that beams signal between a pair of transmitter and receiver across the passage. The gate remains open until the entering car crossed and blocks the blinking infra-red beam. This is made to prevent the gate’s bar from doing any damage to the vehicle passing through. At the OUT-gate, the control mechanism consists of two pairs of infra-red sensors arrangement. When a car arrives at the passageway, it blocks a blinking infra-red beam. This break in the infrared beam is detected by the microcontroller which is at the center of the barrier system operation. Under the command of the microcontroller, the actuator (which is made of a pair of DC motor arms) is energized to open the gate and remains so until the second sensor arrangement on the other side of the gate is crossed. As shown in figure 2, the barrier system was microcontroller based and as a result, a microcontroller, PIC 18F452 occupied the center of the barrier system operation to provide the control logic. The control unit was made up of the following components: PIC 18F452 microcontroller; MAX 232 UART; ULN 2003A IC and ICSP connectors. MAX 232 UART is used to interface the magnetic card reader with the PIC18F452; it is configured to work at 9600 baud rate, which is the baud rate of the magnetic card reader. ULN 2003A IC is used to interface the DC motors that control the lever arm of the barrier system to the microcontroller, because each of the motors operates at 12V, 0.3A while the microcontroller operates at 5V, 200mA. Also, the motor is an inductive load capable of inductive kick when voltage supply to its terminal is cutoff.

A. The Power Supply Unit The power supply unit for the entire barrier system is made up of the followings: 55W Solar panel which converts photons of energy from the Sun into electrical energy; solar charge controller which provides the intelligence for the control of solar power conversion as well as charging of the battery; a 12V, 62AH dry cell battery; rectifier circuit; and automatic switchover; and battery charger circuit which charges the battery from main supply. The battery charger includes overcharge protection circuitry to prevent battery damage. As soon as the battery is fully charged, a float is maintained to keep it at full charge. The block diagram of power supply unit is shown in figure 1. B. The Gate Barrier Unit This unit comprises of 12V DC motors and rectangular hollow aluminum bars. The span of an entrance (say IN) in the prototype is divided into two equal halves of 0.5 meter each, making a total of 1meter for the entrance. Each half is provided with rectangular hollow aluminum bar attached to a DC motor arm. The rating of DC motor arms employed in this work is 1/4Hp, 12V, 0.3A. The rectangular hollow aluminum bars provide the actual physical barrier. They are raised or brought down to open or block the passage as may be required. The dimension of the rectangular hollow aluminum bar for each half is 500mm by 5mm by 2.5mm. 494

International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, Volume 2, Issue 11, November 2012) This inductive kick is capable of injecting a very high voltage of short duration. A transient voltage of such magnitude is capable of damaging delicate electronic components such as PIC18F452. Five ICSP connector types are employed to expand and extend the pins of ICs used in the design to ease connections to peripherals. These are: J1 which is a generic header block with five ports. It connects directly to pins 38-to-40 of PIC18F452. J2 a generic header block with two ports. It is connected to pins 7 and 8 of MAX232. J3; J4; and J5 each of these is a SIL connector block with eight ports. J3 is connected to pins 9to-16 of ULN2003A; J4 is connected to pins 15-to-26 of PIC18F452 while J5 is connected to pins 33-to-40 of PIC18F452. As stated earlier, at the IN-gate magnetic card access is used, where magnetic stripe writer U-CRW01 was employed. The U-CRW01 is a magnetic card writer for reading and encoding magnetic cards according to ISO standard. It could write all three tracks on magnetic cards and process all commercial card types. The magnetic card reader is connected to the microcontroller via RS232. RS232 uses three pins - TX (Transmit) for sending data to the microcontroller; RX (Receive) for receiving data from the microcontroller; and GND ground return terminal shared by the entire circuit. When a card is swiped, the data read from it is sent to the microcontroller for appropriate action. A pair of infra-red transmitter and receiver is employed to realize a sensor arrangement. The infra-red transmitter is a LED which blinks at 38 KHz. This frequency is chosen because modulating at this frequency achieves optimal pickup at the infra-red receiver IC. The infra-red sensor (a pair of infra-red transmitter and receiver) is connected to the PIC18F452 microcontroller via ICSP connector. This infra-red sensor detects the passing of an automobile when the beam it blinks repeatedly is broken. This occurs when a car is in the passageway and blocks the infra-red signal path. This break in infra-red beam is detected by the microcontroller which is at the center of the barrier system operations.

After confirming this PB1 button would be pressed to open the gate for the car to gain entrance. The barrier remains in that position until the return button PB2 is pressed to close the barrier. At the other entrance i.e. OUTgate two indoor buttons (PB1 and PB2) are provided as well to control exit out of the park with an officer in position to operate the buttons as appropriate. The whole arrangement was as shown below in figures 5 and 6 for the control of an entrance. Table 1 gives the truth table for the operation of the relays. For this second design case where the means of control involved the use of indoor push-buttons and gang of electric relays, means of opening and or closing the physical barriers was purely by the use of the push buttons provided at each of the entrance to ensure flow of electricity to power the motor, which in turn actuate the motors, be it IN or OUT. TABLE 1 The truth table for the operation of the barrier using relays RL1 – RL4

RL1

RL2

0 1 0 1

0 0 1 1

Gate Open 0 0 0 1

RL3

RL4

0 1 0 1

0 0 1 1

Gate Close 0 0 0 1

IV. CONSTRUCTION AND TESTING For the prototype, a rectangular steel plate is made to hang each of the motor on which a section of 0.5m length of aluminum bar is attached. The dimension of each of the plate is 35cm by 25cm. Each of the plate is welded on 37cm length angular bar to act as stand on either side of each of the entrances. The battery charger circuit was enclosed in a plastic casing to check the effect of weather while a metallic pole that is 7m high was erected for mounting of solar panel. In the design involving magnetic card encoder/reader and the PIC, sensitive electronics that comprises of PIC 18F452, MAX 232 and ULN2003A were enclosed in a plastic casing to check the effect of weather. For the second approach that involved use of electric relays and in-door push buttons for control of the barrier system, the assembly of the relays was attached to one of the plate in each of the entrances. Connecting wires are then used to link the other plate carrying the remaining half section of the entrance.

Design involving Push Buttons: The barrier system employed in-door push buttons to control access at the two entrances. The logic is provided by a bank of four electric relays, working in pair for opening (RL1 and RL2) and closing (RL3 and RL4) of the barrier system respectively. When a car approaches the IN-gate, the operator checked the status of the approaching car whether it belongs to staff or not.

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International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, Volume 2, Issue 11, November 2012) The whole arrangement was then replicated for the other entrance. Thus a total of eight relay units were required for both entrances. The control unit after design using Proteus was simulated via use of the same software. The simulation could not be completed because there was no model for the magnetic card encoder/reader, which was one of the key components of the design in the first approach. The second approach was simulated and was satisfactory. The battery charger on the hand was simulated through the use of PSpice software. The output of this exercise gives 14.5V, which is enough to ensure the battery is adequately charged to power the entire system. Prior to power up, the circuit board assembly was checked for poor soldered connections and possible short-circuits between closely spaced components. When this was established absent, the circuit was powered on. The performance was found satisfactory.

REFERENCES [1 ] Wikipedia (updated January 2010), the free encyclopedia.html, “Electric Gates motor Types” [2 ] www.TopBits.com, “How magnetic card reader works” [3 ] Wikipedia (updated January 2010), the free encyclopedia.html, “Magnetic stripe card” [4 ] Martins Bates (2006), Interfacing PIC Microcontrollers Embedded Design by Interactive Simulation [5 ] J. Sanchez and M. P. Canton (2007), Microcontroller Programming, The Microchip PIC by, CRC Press [6 ] E. Lorenzo, "Solar Electricity: Engineering of Photovoltaic Systems" (Progensa), 59-70 [7 ] Aldous Scott (2005), “How Solar Cells Work”, http://science.howstuffworks.com/solar-cell.htm [8 ] A. Shah. P. Torres, R. Tscharner, N. Wyrsch, H. Kenner (1999), “Photovoltaic Technology: The case for thin film Solar Cells”, Science 285, pp. 692-698 [9 ] LM350 Datasheet 2009, www.fairchildsemi.com [10 ] LM301 Motorola Analog IC Data, www.datasheetcatalog.com [11 ] PIC 18FXX2 Datasheet, www.microchip.com [12 ] MAX 232 Datasheet, www.datasheetcatalog.com

V. CONCLUSION This paper centered on the design, construction and deployment of an automated barrier system to a car park. In this work, a prototype of a gate system was designed using combination of a small DC motors extracted from the wiper arm of Mercedes Benz car and aluminum bars. Two approaches were explored, in the first case, the system intelligence was provided by PIC 18F452 which was at the center of the control unit of the barrier system. In the second approach, four electric relays and two in-doors push buttons were employed for the control of the barrier system in each of the two entrances. Two of the relays work in conjunction with the push button designated for opening of the barrier while the remaining two reversed the direction of the movement of the barrier when the second push button for closing of the barrier is operated. The automated barrier system design and constructed in this work is an effort in the right direction. It gives value to the job of officers manning the gate and enhances their performances. Also, when deployed in a car park it can reduces the required number of officers manning a gate thereby creating room for better and efficient utilization of available workforce to an organization. Lastly, the automated barrier system is not difficult to construct and the components/modules are readily available in the market. Field deployment only requires a bigger motor that has gear to effectively and efficiently hold firm the bar that constitute the physical barrier.

SOLAR PANEL

SOLAR CHARGE CONTROLLER

MAINS

AUTO-SWITCH

BATTERY

AUTO-SWITCH

BATTERY CHARGER LOAD RECTIFIER CIRCUIT Figure 1: Block Diagram of Power Supply Unit

PIC18F452

MAX232

ULN2003A

ICSP CONNECTORS

MAGNETIC READER

DC MOTOR ARMS

INFRA-RED SENSORS

Figure 2: Block Diagram of the Control Unit of Design involving PIC18F452

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International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, Volume 2, Issue 11, November 2012)

Figure 3: Circuit Diagram of Control Unit for the Design involving PIC 18F452

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