Project Abstract

Project Overview

MICRO CONTROLLER BASED TOLL TAX SYSTEM

INTRODUCTION:

This project involves Toll Tax System using infrared technology. The term “infrared” refers to a broad range of frequency beginning at top end of those frequencies used for communication and extending up to the low frequency (red) end of the visible spectrum. That means infrared light has a range of wavelength, just like visible light has wavelength that range from red light to violet. “Near infrared” light is closest in wavelength to visible light and “Far infrared” is closer to the microwave region of the electromagnetic spectrum.

Since heat is a form of Infrared light, far infrared detector are sensitive to environmental changes-such as a person moving in the field of view.

In this we are using infrared for sensing the vehicle and there is FND displaying the amount to be paid off.

Hardware requirements:

1)      Microcontroller AT89C51/89s52

2)      LM7805 Regulator

3)      Power Supply

4)      Function Numeric Display

5)      Resistors

6)      Capacitors

7)      Transistors

8)      LEDs

9)      Connectors

10)  IR Transmitter

11)  IR Receiver

12)  Pressure Switch

Software requirements:

1)      Assembler of ATMEL microcontroller series

2)      PADS for PCB designing

AIM OF THE PROJECT

The aim of this project is to design a high tech toll tax system using microcontroller so that the vehicles need not to stand in a queue for a long time to pay the toll  tax . Now by using a microcontroller tax paying become very simple ,There is a alarm which blow as soon as it detect a vehicle ,a vehicle can be sensed through an IR sensor ,and the amount to be paid off is also display ,when driver paid off the tax it allow to move further .This system takes very small time, thus prevent the jam to occur .

WORKING OF THE PROJECT – TOLL TAX MANAGEMENT SYSTEM PROJECT

This system is based on transmission and reception of IR. IR sensors are sensitive to car moving in the field of view. For car parking a region IR is send in that region from one end and it is received on the other end. When a car enters in that region it cut the infrared, so at that moment receiver doesn’t detect any signal and absence of IR is sensed by receiver which in turn generate a low pulse on the microcontroller pin ,then microcontroller read the pin and run according to software loaded in it and blow an alarm. The transmitter and receiver are connected to the main device. The main device has power supply, micro controller and a FND connected to it.

POWER SUPPLY SECTION:
Consists of:

1. RLMT Connector— It is a connector used to connect the step down transformer     to the bridge rectifier.

1. Bridge Rectifier — It is a full wave rectifier used to convert ac into dc , 9-15v ac made by transformer is converted into dc with the help of rectifier.

1. Capacitor: —–It is an electrolytic capacitor of rating 1000M/35V used to remove the ripples. Capacitor is the component used to pass the ac and block the dc.

1. Regulator: —-LM7805 is used to give a fixed 5v regulated supply.

1. Capacitor: —–It is again an electrolytic capacitor 10M/65v used for filtering to give pure dc.

1. Capacitor:  —– It is an ceramic capacitor used to remove the spikes generated when frequency is high(spikes).

So the output of supply section is 5v regulated dc.

MICROCONTROLLER     SECTION:

Requires three connections to be successfully done for it’s operation to begin.

1. +5v   supply: This +5v supply is required for the controller to get start which is provided from the power supply section. This supply is provided at pin no.31and 40 of the 89c51 controller.

1. Crystal Oscillator:A crystal oscillator of 12 MHz is connected at pin no.19,x1 and pin no.18,x2 to generate the frequency for the controller. The crystal oscillator works on piezoelectric effect.The clock generated is used to determine the processing speed of the controller. Two capacitors are also connected one end with the oscillator while the other end is connected with the ground. As it is recommended in the book to connect two ceramic capacitor of 20 pf—40pf to stabilize the clock generated.

1. Reset section: It consists of an rc network consisting of 10M/35V capacitor and one resistance of 1k. This section is used to reset the controller connected at pin no.9 of AT89c51.

DISPLAY SECTION:

FND ( Functional Numeric Display)

FND is similar to the seven segment display but it has one more segment db for decimal. It has eight leds. The current specification for an led is 5MA-25MA. The safe range for the current to select is the mid value that is 12MA and voltage required is 5v so the resistance required to limit the current in led is calculated by the ohm’s law i.e. V=IR, R=V/I   and hence R comes to about 470ohm.

FND are connected to the microcontroller at i/o port like p0,p1,p2,or p3

And also a transistor is required to get the fnd on or off. The base resistance required for the transistor is also 470ohm.

The message to be displayed on fnd is programmed through software.

RELAY SECTION:

RELAY is an isolator and an electrical switch. The relay used is 12V-5A.To control the operation of relay an NPN transistor BC547 has been used. Whenever high signal comes at the base of NPN transistor it is switched on and whenever low arrives it is switched off. Base of the transistor is connected with the I/O pin of the microcontroller. Base resistance of 1k5 is connected at the base of the transistor. Whenever low is sensed at the pin of microcontroller transistor gets off and the output of the collector becomes high and the relay which is connected at the output of the collector becomes off. The reverse action of it takes place when high is sensed at the pin of microcontroller.

This section also consists of pull up & pull down resistance. A 2k2 resistance is used as pull up. In any case when more than 5v comes then pull up resistance sinks the excess voltage & maintains 5v. If pull up is not used then the 12v of relay can damage the processor when the transistor BC547 is on. A pull down resistor of value 2k2 is also used.