01-05-2013, 04:10 PM
Traffic Congestion Alert System Using GSM Report
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INTRODUCTION
BACKGROUND
The increase in the number of vehicles has led to Traffic congestion. During the busy hours of a day, the traffic is at its peak and there are various problems related to traffic congestion. One such problem is fuel consumption. An average of 90 minutes is spent daily by a vehicle in congested traffic. People forget to switch off the engines which cause wastage of the non renewable resources such as petrol, diesel and LPG. A car wastes 2.5 litres of fuel and two wheelers waste 0.75 litres of fuel in traffic jam per day. The cost of fuel wasted by city car is 7.5 cr and two-wheelers are 2.5 cr per day. The government subsidy on the wasted fuel is 1.5 cr per day. This incurs a heavy revenue loss to the country.
For the emergency conditions such as ambulance, fire engines to pass through, the congestion poses a hindrance. To recover for the lost time spent in congestion people tend to hurry and disperse the congestion, causing accidents. Indian roads witness one accident every minute and one death in road mishap every four and half minute, according to the latest report of the road, transport and highway ministry. Similarly the report estimates that these road mishaps left 5.2 lakh people injured.
The smoke released from the vehicles and the honking of the horns causes air and noise pollution. India is the world’s fourth largest carbon dioxide emitter with emission amounting to 1.34 billion tons per annum behind China, US and Russia. Even if India holds on to its promise of keeping its per capita emissions lower than that of developer economies, we will soon overtake Russia to become the third largest emitter.
To overcome these problems, a system has to be designed which can alert for congestion. “Traffic congestion alert system using GSM” does the needful and thus helps in reducing the traffic congestion.
PROJECT OVERVIEW
“Traffic Congestion Alert System Using GSM” project automatically alerts the traffic congestion condition. It can be implemented in the lanes and junctions which carry heavy traffic. Sensors are placed on roads to monitor the traffic condition. In each junction a transmitter and receiver will be present along with a LCD screen for display of message. When congestion is reported an interrupt is sent to the controller and the corresponding alert, LANE BUSY message is sent to the neighbouring junctions. The GSM modem (SIM 300) is used for transmitting and receiving messages on GSM network. The alert message is received on the surrounding junctions using GSM modem (SIM 300). This message will be displayed on the respective LCD screen. Thus the rider is alerted for the congestion condition beforehand. This facilitates the rider in taking an alternate congestion free route, avoiding being stuck in the traffic jam (congestion). After the particular lane clears, the LANE CLEAR message is also displayed. This helps in diverting the traffic and hence reducing congestion.
DESCRIPTION
This chapter contains the block diagram description, hardware and software constituents of the project. Also explains the working and implementation of this project with an example.
The Block Diagram includes transmitter and receiver as shown in Figure 2.1, which gives an overall description of the project. Using GSM system the data is transferred from the transmitter to the receiver. This data will be displayed on both the LCD screens placed at transmitting and receiving side.
HARDWARE DESCRIPTION
The hardware includes power supply, sensors, PIC microcontroller, LCD screen, MAX232, RS232 and GSM modem.
POWER SUPPLY
Figure 2.2 shows ac to dc converter which is used for powering the microcontroller section and relay driving sensor section. These two transformers are used to step down the 230V ac main supply to 12V ac supply. Current handling capacity of the transformer is 500mA.
The 12V ac output is given at the power supply regulation stage. It consists of bridge rectifier using diode D1 to D4 of 1N4007. The current handling capacity of this diode is 1A and voltage handling capacity is 1000V. These 4 diodes are used to rectify the low voltage, i.e. 12V ac into 12V dc.
SENSORS
Sensor is a device that measures the physical quantity and converts it into a signal which can be read by an instrument. The two types of sensors used here are Leaf switches and Reed switches.
Leaf switch is an electric switch with a button (or other moving part) and two strips of metal that make contact when the button is pushed as shown in Figure 2.3. The circuit is only closed when the button is held down. So these switches are best suited for generating short pulses that trigger an action in the circuit. They are commonly used in everyday appliances like door bells and joystick fire buttons. Leaf switches are silent and durable since there is a minimum amount of moving parts involved.Reed switch contains a pair (or more) of magnetisable, flexible, metal reeds whose end portions are separated by a small gap when the switch is open as shown in Figure 2.4. The reeds are hermetically sealed in opposite ends of a tubular glass envelope. A magnetic field will cause the reeds to come together, thus completing an electrical circuit. The stiffness of the reeds causes them to separate, and open the circuit, when the magnetic field ceases.
PIC16F877A MICROCONTROLLER
The 16F877A is a low-power; high performance CMOS 8-bit microcomputer with 8K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using PIC’s high-density non-volatile memory technology and is compatible with the industry-standard PIC instruction set and pin out. The
on-chip Flash allows the program memory to be reprogrammed in-system or by a
conventional non-volatile memory programmer. By combining a versatile 8-bit CPU with
Flash on a monolithic chip, the PIC is a powerful microcomputer which
provides a highly-flexible and cost-effective solution to many embedded control
applications.
The following are the main features of this micro-controller as shown in Figure 2.6. It is compatible with PIC Products. There are 8 interrupt sources; hence many interrupts can be serviced. It has 8K Bytes of In-system reprogrammable Flash Memory. Its endurance is 1000 write/erase cycles. In a range of 0 Hz to 24 MHz it is in full static operation. Three-level Program Memory Lock is available. It consists of 256 x 8 bit internal RAM and 32 Programmable I/O lines. There are three 16-bit Timer/Counters. It can operate in Low-power Idle and Power-down Modes.
LCD SCREEN
A liquid crystal display (LCD) is a thin, flat display device made up of any number of colour or monochrome pixels arrayed in front of a light source or reflector as shown in Figure 2.7. It is often utilized in battery-powered electronic devices because it uses very small amounts of electric power. JHD 162A is LCD that has many features. There are 2 lines and each line take 16 characters. The module dimension is 80.0mm*36.0mm*9.7mm. The area is 66.0mm*16.0mm, wherein active area is 56.2mm*11.5mm. The Dot size is 0.55mm*0.65mm and the Dot pitch is 0.60mm*0.70mm. The each Character size is 2.95mm*5.55mm and the Character pitch is 3.55mm*5.95mm.
RS232
To allow the data compatibility among data communication equipment made by various manufactures, an interfacing standard called RS232, as shown in Figure 2.8, was set by the Electronics Industries Association (EIA) in 1960.
RS232 is the widely used serial I/O interfacing standard. In RS232, 1 is represented by -3 to -25 V, while a 0 bit is +3 to +25 V, making -3 to +3 undefined. For this reason to convert any RS232 to a microcontroller system we must use voltage converter such as MAX232 to convert the TTL logic level to the RS232 voltage level, and vice versa.
WORKING
The Figure 2.10 shows the circuit diagram of the Transmitter. Here there are 8 sensors which are placed on 8 lanes. These sensors are connected to the input pin (2, 3 4, 5, 6, 7, 15 and 16) of the PIC16F877A microcontroller. The controller will be polling all the sensors continuously. When any of the sensor switches is closed, it will interrupt the controller through the respective pins. The controller will then execute the interrupt sub routine of concern and the corresponding message will be sent to the LCD Screen via output pins (33, 34, 35, 36, 37, 38, 39 and 40) of the controller. The pins 27, 28 and 29 of the controller are used to Control the 16 x 2 LCD Screen. This message is even sent to the receiver via GSM modem wirelessly. The GSM modem and the controller are connected using the RS232 interfacing which uses MAX232, a line driver via the pins 25 and 26 of the controller.
The receiver circuit is same as the transmitter circuit as shown in Figure 2.10. When the data is received by the GSM modem at the receiver from the GSM modem at the transmitter, the receiver modem will decode the encoded data. This decoded data will be sent to the PIC via the serial interface RS232.
The PIC converts the Serial input to parallel output and sends the message to the LCD Screen via the output pins of the controller.
Mobile Station (MS)
The mobile station (MS) is the device that provides the radio link between the GSM subscriber and the wireless mobile network. In the GSM system, the MS provides subscribers the mean to control their access to the PSTN (Public Switch Telephone Network) and PDN (Public Data Network) and also to facilitate their mobility once connected to the network .The MS is constantly monitoring messages being broadcast from base transceiver system (BTS) to support the setup and clearing of radio channels used for the transmission of various forms of subscriber traffic. The GSM system also makes use of Subscriber Identity Module or SIM card that when inserted into the MS makes it functional. The SIM is a smart card that is issued to the subscriber when the subscriber signs up for service with the wireless network operator. The card contains the subscriber’s IMSI (International Mobile Subscriber Identity) number, the mobile MSISDN (Mobile Subscriber Integrated Services Digital Network), a SIM personal identification number (PIN), security /authentication parameters, and address book contact information stored by the subscriber. The SIM card also stores SMS messages that the subscriber receives and saves. In GSM standard, the MS consists of two elements: the mobile equipment (ME), which is the physical phone itself, and the SIM card.
Base Station System (BSS)
The base station system (BSS) is the link between the MS and the GSM mobile –services switching centre (MSC). The BSS consists of two elements: a base transceiver system (BTS) and the base station controller (BSC). The BTS communicates with the MS over air interface using various protocols designed for the wireless channel. The BSC communicates with the MSC through the use of standard wire line protocols. The BSC and BTS communicate with each other using LAPD (Link Access Protocol for D channel), which is the data link protocol used in ISDN. The basic components of the BTS are radio transceiver units, a switching and distribution unit, RF power combining and distribution units, an environmental control unit, a power system , and a processing and database storage unit. The BTS is physically located near the antenna for the cell site. Typically, an RBS (radio base station) may consist of three BTSs that service a standard sectorized cell site.
Operation and maintenance subsystem (OMSS)
The OMSS is responsible for handling system security based on validation of identities of various telecommunications entities. These functions are performed in the Authentication Centre (AuC) and EIR (Equipment Identity Register). The AuC is accessed by the HLR to determine whether an MS will be granted service. The EIR provides MS information used by the MSC. The EIR maintains a list of legitimate, fraudulent or faulty MSs. The OMSS is also in charge of remote operation and maintenance functions of the PLMN. These functions are monitored and controlled in the OMSS. The OMSS may have one or more Network Management Centers (NMCs) to centralize PLMN control.
The operational and maintenance centre (OMC) is the functional entity through the service provider monitors and controls the system. The OMC provides a single point for the maintenance personnel to maintain the entire system. One OMC can serve multiple MSCs.
Security in the System
In a secured spatial messaging system, a user can be sure that the message he is reading is really written by the mentioned author, that nobody has modified the content of the original message, and that all other available messages at this place are available. More precisely, a secured spatial messaging system has to respect the "traditional" security services that are:
• Confidentiality. Protection of the information against divulgations.
• Integrity: Protection of the information against modifications.
• Availability: Information is always available.
• Entity authentication: The author can be identified.
• Data origin authentication: Information can be linked to its author.
• Non-repudiation: The author cannot repudiate a message.
• Non-duplication: Protection against copying the information.
• Anonymity: The real-life identity of the users must be preserved.
These security services are well-known [12] and won't be discussed here. There are many implementations that already proved their efficiency.
Trust in the System
The previous section discussed the security aspects of spatial messaging. A reader can be sure that a given message is really posted by its signer and that the content has not been modified since. But even if the reader can be sure about the author's identity, it is useless if they do not know each other. This section discusses how to add trust information on spatial messages so that the reader can evaluate the reliability of a message.
Trust is a very complex concept. Even if it is part of everyday life, different people give also different definitions of what trust is. This observation is even strongly accentuated when we try to explain how to build a trust relation between machines, or between humans and machines. The authors' own point of view of trust can be found in [14]. One reason is that most models are only designed and specialized for peer-to-peer files sharing systems. For example, these models do not take time into account.