Railway crossing system

Line Follower Robot11Overview A line follower robot is basically a robot designed to follow a line or path already predetermined by the user. This line or path may be as simple as a physical white line on the floor or as complex path marking schemes e.g. embedded lines, magnetic markers and laser guide markers. In order to detect these specific markers or lines, various sensing schemes can be employed. These schemes may vary from simple low cost line sensing circuit to expansive vision systems. The choice of these schemes would be dependent upon the sensing accuracy and flexibility required.

2Block Diagram3 IR sensorIR sensor

L293D motor driver IC8051 MicrocontrollerDC motorComponents RequiredL293D IC 1AT 89C2051 IC 1LM 358 IC 1LM 7805 1Preset 10 K 2LED 3Diode (IN4007) 2Crystal OSC. (11.0592) MHz 1 Capacitor (33pf) 2Capacitor (10uf) 3Resistance (1K) 3 Resistance(470 ohm) 2 Resistance (10K) 3 Robot Chassis 1 IR Sensor (pair) 2Wheels 2Motors (20 RPM) 2Free Wheels (caster) 1

4POWER SUPPLY

230 V AC 50 Hz5V DC 12V step down transformerFilter(470f)5v RegulatorBridge rectifier

5Resistance6

Cont7Resistance is the opposition that a substance offers to the flow of electric current. It is represented by the uppercase letter R. The standard unit of resistance is the ohm, sometimes written out as a word, and sometimes symbolized by the uppercase Greek letter omega. When an electric current of one ampere passes through a component across which a potential difference (voltage) of one volt exists, then the resistance of that component is one ohm.In general, when the applied voltage is held constant, the current in a direct-current (DC) electrical circuit is inversely proportional to the resistance.Capacitance8

Cont9A capacitor is a passive electronic component that stores energy in the form of an electrostatic field. In its simplest form, a capacitor consists of two conducting plates separated by an insulating material called the dielectric. The capacitance is directly proportional to the surface areas of the plates, and is inversely proportional to the separation between the plates. Capacitance also depends on the dielectric constant of the substance separating the plates.The standard unit of capacitance is the farad, abbreviated. This is a large unit; more common units are the microfarad, abbreviated F (1 F =10-6F) and the picofarad, abbreviated pF (1 pF = 10-12 F).Diode10

Cont11The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction). Thus, the diode can be viewed as an electronic version of a check valve. This unidirectional behavior is called rectification.diodes can have more complicated behavior than this simple onoff action, due to their nonlinear current-voltage characteristics. Semiconductor diodes begin conducting electricity only if a certain threshold voltage or cut-in voltage is present in the forward direction (a state in which the diode is said to be forward-biased).

LM358IC12

Cont13The LM358 is a very common low-power, dual channel op-amp. They are widely used as pre-amplifiers in many audio devices.They have a wide frequency range and fast response time, and run over a 3 to 32 volt supply range.

AT89C205114

Cont15 The AT89C2051 is a low-voltage, high-performance CMOS 8-bit microcomputer with 2K bytes of Flash programmable and erasable read-only memory (PEROM). By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C2051 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications. Features: 128 x 8-bit Internal RAM 15 Programmable I/O Lines Two 16-bit Timer/Counters Six Interrupt Sources IC780516

Cont17Voltage regulator IC's are the ICs that are used to regulate voltage.IC 7805 is a 5V Voltage Regulator that restricts the voltage output to 5V and draws 5V regulated power supply. It comes with provision to add heat sink.The maximum value for input to the voltage regulator is 35V. It can provide a constant steady voltage flow of 5V for higher voltage input till the threshold limit of 35V. If the voltage is near to 7.5V then it does not produce any heat and hence no need for heat sink. If the voltage input is more, then excess electricity is liberated as heat from 7805.It regulates a steady output of 5V if the input voltage is in rage of 7.2V to 35V. Hence to avoid power loss try to maintain the input to 7.2V. In some circuitry voltage fluctuation is fatal (for e.g. Microcontroller), for such situation to ensure constant voltage IC 7805 Voltage Regulator is used.

L293D18

Cont19 L293D is a typical Motor driver or Motor Driver IC which allows DC motor to drive on either direction. L293D is a 16-pin IC which can control a set of two DC motors simultaneously in any direction. It means that you can control two DC motor with a single L293D IC. Dual H-bridge Motor Driver integrated circuit (IC). here are two Enable pins on l293d. Pin 1 and pin 9, for being able to drive the motor, the pin 1 and 9 need to be high. For driving the motor with left H-bridge you need to enable pin 1 to high. And for right H-Bridge you need to make the pin 9 to high. If anyone of the either pin1 or pin9 goes low then the motor in the corresponding section will suspend working. Its like a switch.

Crystal Oscillator20

Cont21A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency. This frequency is commonly used to keep track of time (as in quartz wristwatches), to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. The most common type of piezoelectric resonator used is the quartz crystal, so oscillator circuits incorporating them became known as crystal oscillators but other piezoelectric materials including polycrystalline ceramics are used in similar circuits.Quartz crystals are manufactured for frequencies from a few tens of kilohertz to hundreds of megahertz. More than two billion crystals are manufactured annually. Most are used for consumer devices such as wristwatches, clocks, radios, computers, and cell phones. Quartz crystals are also found inside test and measurement equipment, such as counters, signal generators, and oscilloscopes.

Motor22

Cont23 30RPM 12V DC geared motor is high quality low cost DC geared motor. It is very useful in robotics applications. Very easy to use and available in standard size. Nut and threads on shaft to easily connect and internal threaded shaft for easily connecting it to wheel. LED24

ContA light-emitting diode (LED) is a two-lead semiconductor light source. It is a p-n junction diode, which emits light when activated.When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.25Working Of Project In this project we are using LM358 which is an OPM IC it transmit the analog value coming from the sensor to the micro controller. We are placing two IR sensors in our project to detect the line; both the sensors are placed at the end side of the line which robot has to follow. IR work on a principal that if black surface come then the IR light will not revert but whenever the white surface come it will revert and send a bit to the connected IR photodiode. So when our robot is moving whenever the line turn then the sensors will detect the line and send the bit to the OPM IC which convert this analog signal into to digital bit and send it to the micro controller. According the coding in the micro controller it will detect that at what end line is turning and send a bit to the IC L293D, which is a motor driver IC to turn the robot according to the direction of the line.

26ApplicationsGuidance system for industrial robots moving on shop floor etc.Industrial applications.Home applications.

27Future AspectsSmarter versions of line followers are used to deliver mails within office building and deliver medications in a hospital.This technology has been suggested for running buses and other mass transit systems and may end up as a part of autonomous cars navigating the freeway.

28Ouery???Query.???29Thank You 30