SPEED DETECTOR FOR HIGHWAYS

INDEX

CONTENTS

1. Figures locations

2. Abstract

3. Introduction

4. Block Diagram

5. Block Diagram Description

6. Schematic

7. Schematic Description

8. Hardware Components

Power supply

Microcontroller

LCD

IR TRANSMITTER

IR RECEIVER

9. Circuit Description

10.Software components

a. About Keil

b. Embedded ‘C’

11. KEIL procedure description

12.Conclusion (or) Synopsis

13. Future Aspects

ABSTRACT

A system designed to record and report on discrete activities within a process is

called as Tracking System. In the same procedure we have developed a methodology of

vehicle speed & direction system for robotics to control and achieve accurate direction

speed for a class of non-linear systems in the presence of disturbances and parameter

variations by using wireless communication technique.

In this methodology we are using a micro controller, resulting in the state

trajectory 'sliding' along path-varying slides on the surface. This idealized control law

achieves perfect direction & speed however. The method is applied to the control of a

two-link manipulator handling variable loads in a flexible manufacturing system

environment.

In our project we use IR sensors to detect the presence of a vehicle. According to

this project, 2 IR sensors are placed apart with a fixed known distance. When ever IR

rays are interrupted by a vehicle during first sensor the count up timer is started. When

the other IR sensor senses the presence of vehicle, the count up timer is stopped. As the

distance and time the IR receiver receives the IR signals is noted by microcontroller and

from that we need to calculate speed. Here speed is calculated from the well known

formula of speed which is distance/time.

In this circuit we are using LCD display for indicating the speed. It is easy to set

up and supports the required hardware. To design a vehicle that supports the newest

technology available will be more expensive than boards that are already close to

obsolete.

INTRODUCTION

BLOCK-DIAGRAM

BLOCK DIAGRAM EXPLANATION: The project “SPEED CHECKER FOR HI-WAYS” is made to calculate the speed of the vehicle by using the following methodology.

In this project we use IR sensors to detect the presence of a vehicle. According to

this project, 2 IR sensors are placed apart with a fixed known distance. When ever IR

rays are interrupted by a vehicle during first sensor the count up timer is started. When

the other IR sensor senses the presence of vehicle, the count up timer is stopped. As the

distance and time the IR receiver receives the IR signals is noted by microcontroller and

POWER SUPPLY

MICROCONTROLLER

LCD

IR-TX 2

IR-Rx 1

IR-Rx 2

IR-TX 1

from that we need to calculate speed. Here speed is calculated from the well known

formula of speed which is distance/time.

The LCD is used to display the speed of the vehicle. The microcontroller is used to monitor the all control operations needed for the project.

Schematic diagram:

SCHEMATIC DESCRIPTION:

Power Supply:

The main aim of this power supply is to convert the 230V AC into 5V DC in

order to give supply for the TTL or CMOS devices. In this process we are using a step

down transformer, a bridge rectifier, a smoothing circuit and the RPS.

At the primary of the transformer we are giving the 230V AC supply. The

secondary is connected to the opposite terminals of the Bridge rectifier as the input. From

other set of opposite terminals we are taking the output to the rectifier.

The bridge rectifier converts the AC coming from the secondary of the

transformer into pulsating DC. The output of this rectifier is further given to the smoother

circuit which is capacitor in our project. The smoothing circuit eliminates the ripples

from the pulsating DC and gives the pure DC to the RPS to get a constant output DC

voltage. The RPS regulates the voltage as per our requirement.

Lcd:

The data pins of the LCD(i.e. pin mo 7 to 14 are connected to the port 0 of the

microcontroller. The control pins are connected to the port 2.7 to p2.5 respectively.

IR section:

The IR LED is used as the IR transmitter, which is connected by using the

resistor logic as shown in the schematic.

The IR receiver is connected by using the transistor logic whose collector is

connected to the base of the transistor. The base of the transistor is connected to the photo

diode through the resistor.

Hardware Components

Power supply

Microcontroller

LCD

IR TRANSMITTER

IR RECEIVER

HARDWARE EXPLANATION:

MICRO CONTROLLER (AT89S51)

Introduction

A Micro controller consists of a powerful CPU tightly coupled with memory,

various I/O interfaces such as serial port, parallel port timer or counter, interrupt

controller, data acquisition interfaces-Analog to Digital converter, Digital to Analog

converter, integrated on to a single silicon chip.

If a system is developed with a microprocessor, the designer has to go for external

memory such as RAM, ROM, EPROM and peripherals. But controller is provided all

these facilities on a single chip. Development of a Micro controller reduces PCB size and

cost of design.

One of the major differences between a Microprocessor and a Micro controller is

that a controller often deals with bits not bytes as in the real world application.

Intel has introduced a family of Micro controllers called the MCS-51.

Figure: micro controller

Block diagram:

Figure: Block diagram

Features:

• Compatible with MCS-51® Products

• 4K Bytes of In-System Programmable (ISP) Flash Memory

– Endurance: 1000 Write/Erase Cycles

• 4.0V to 5.5V Operating Range

• Fully Static Operation: 0 Hz to 33 MHz

• Three-level Program Memory Lock

• 128 x 8-bit Internal RAM

• 32 Programmable I/O Lines

• Two 16-bit Timer/Counters

• Six Interrupt Sources

• Full Duplex UART Serial Channel

• Low-power Idle and Power-down Modes

Description

The AT89S51 is a low-power, high-performance CMOS 8-bit microcontroller with 4K bytes of

in-system programmable Flash memory. The device is manufactured using Atmel’s high-

density nonvolatile memory technology and is compatible with the industry- standard 80C51

instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed

in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-

bit CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S51 is a

powerful microcontroller which provides a highly-flexible and cost-effective solution to many

embedded control applications.

Pin diagram:

Figure: pin diagram of micro controller

Pin Description:

VCC - Supply voltage.

GND - Ground.

Port 0:

Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink

eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high-impedance

inputs. Port 0 can also be configured to be the multiplexed low-order address/data bus during

accesses to external program and data memory. In this mode, P0 has internal pull-ups. Port 0

also receives the code bytes during Flash programming and outputs the code bytes during

program verification. External pull-ups are required during program verification.

Port 1:

Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output buffers

can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by

the internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are externally being

pulled low will source current (IIL) because of the internal pull-ups. Port 1 also receives the

low-order address bytes during Flash programming and verification.

Port 2:

Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output buffers

can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by

the internal pull-ups and can be used as inputs. As inputs, Port 2 pins that are externally being

pulled low will source current (IIL) because of the internal pull-ups. Port 2 also receives the

high-order address bits and some control signals during Flash programming and verification.

Port 3:

Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output buffers

can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by

the internal pull-ups and can be used as inputs. As inputs, Port 3 pins that are externally being

pulled low will source current (IIL) because of the pull-ups. Port 3 receives some control

signals for Flash programming and verification. Port 3 also serves the functions of various

special features of the AT89S51, as shown in the following table.

RST:

Reset input. A high on this pin for two machine cycles while the oscillator is running

resets the device. This pin drives High for 98 oscillator periods after the Watchdog times out.

The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the

default state of bit DISRTO, the RESET HIGH out feature is enabled.

ALE/PROG:

Address Latch Enable (ALE) is an output pulse for latching the low byte of the address

during accesses to external memory. This pin is also the program pulse input (PROG) during

Flash programming. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator

frequency and may be used for external timing or clocking purposes. Note, however, that one

ALE pulse is skipped during each access to external data memory. If desired, ALE operation

can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only

during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the

ALE-disable bit has no effect if the microcontroller is in external execution mode.

PSEN:

Program Store Enable (PSEN) is the read strobe to external program memory. When

the AT89S51 is executing code from external program memory, PSEN is activated twice each

machine cycle, except that two PSEN activations are skipped during each access to external

data memory.

EA/VPP:

External Access Enable. EA must be strapped to GND in order to enable the device to

fetch code from external program memory locations starting at 0000H up to FFFFH. Note,

however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be

strapped to VCC for internal program executions. This pin also receives the 12-volt

programming enable voltage (VPP) during Flash programming.

XTAL1:

Input to the inverting oscillator amplifier and input to the internal clock operating

circuit.

XTAL2:

Output from the inverting oscillator amplifier.

Oscillator Characteristics:

XTAL1 and XTAL2 are the input and output, respectively, of an inverting

amplifier which can be configured for use as an on-chip oscillator, as shown in Figs

6.2.3. Either a quartz crystal or ceramic resonator may be used. To drive the device from

an external clock source, XTAL2 should be left unconnected while XTAL1 is driven as

shown in Figure 6.2.4.There are no requirements on the duty cycle of the external clock

signal, since the input to the internal clocking circuitry is through a divide-by-two flip-

flop, but minimum and maximum voltage high and low time specifications must be

observed.

Fig 6.2.3 Oscillator Connections Fig 6.2.4 External Clock Drive Configuration

Liquid Crystal Display

Introduction to LCD:

In recent years the LCD is finding widespread use replacing LED s (seven-segment LED

or other multi segment LED s). This is due to the following reasons:

1. The declining prices of LCD s.

2. The ability to display numbers, characters and graphics. This is in

contract to LED s, which are limited to numbers and a few characters.

3. Incorporation of a refreshing controller into the LCD, there by relieving the CPU

of the task of refreshing the LCD. In the contrast, the LED must be refreshed by

the CPU to keep displaying the data.

4. Ease of programming for characters and graphics.

USES:

The LCD s used exclusively in watches, calculators and measuring instruments is

the simple seven-segment displays, having a limited amount of numeric data. The recent

advances in technology have resulted in better legibility, more information displaying

capability and a wider temperature range. These have resulted in the LCD s being

extensively used in telecommunications and entertainment electronics. The LCD s has

even started replacing the cathode ray tubes (CRTs) used for the display of text and

graphics, and also in small TV applications.

S p e c i f i c a t i o n s

Number of Characters: 16 characters x 2 Lines

Character Table: English-European (RS in Datasheet)

Module dimension: 80.0mm x 36.0mm x 13.2mm(MAX)

View area: 66.0 x 16.0 mm

Active area: 56.2 x 11.5 mm

Dot size: 0.56 x 0.66 mm

Dot pitch: 0.60 x 0.70 mm

Character size: 2.96 x 5.46 mm

Character pitch: 3.55 x 5.94 mm

LCD type: STN, Positive, Transflective, Yellow/Green

Duty: 1/16

View direction: Wide viewing angle

Backlight Type: yellow/green LED

RoHS Compliant: lead free

Operating Temperature: -20°C to + 70°C

LCD PIN DIAGRAM:

LCD pin description

The LCD discussed in this section has 14 pins. The function of each pin is given in table.

TABLE 1: Pin description for LCD:

Pin symbol I/O Description

1 Vss -- Ground

2 Vcc -- +5V power supply

3 VEE -- Power supply to

control contrast

4 RS I RS=0 to select

command register

RS=1 to select

data register

5 R/W I R/W=0 for write

R/W=1 for read

6 E I/O Enable

7-14 DB0-DB7 I/O The 8-bit data bus

Power supply

The power supplies are designed to convert high voltage AC

mains electricity to a suitable low voltage supply for electronics circuits and other

devices. A power supply can by broken down into a series of blocks, each of which

performs a particular function. A d.c power supply which maintains the output voltage

constant irrespective of a.c mains fluctuations or load variations is known as “Regulated

D.C Power Supply”

For example a 5V regulated power supply system as shown below:

IR transmitter:

IR LED:

Here the IR transmitter is nothing but the IR LED. It just looks like a normal LED but

transmits the IR signals. Since the IR rays are out of the visible range we cannot observe

the rays from the transmitter.

These are infrared LEDs; the light output is not visible by our eyes. They can be used as

replacement LEDs for remote controls, night vision for camcorders, invisible beam

sensors, etc.

Fig 30: IR LED

Advantages:

Infrared LEDs are ideal light sources for use with night vision goggles,

surveillance cameras, medical imaging, recognition and calibration

systems.

Due to their resistance to ambient-light impediments and electromagnetic

interference (EMI), Infrared LEDs enhance the performance of wireless

computer-to-PDA links, collision avoidance systems, automation

equipment, biomedical instrumentation, and telecommunications

equipment.

Solid-state design renders Infrared LEDs impervious to electrical and

mechanical shock, vibration, frequent switching and environmental

extremes. With an average life span of 100,000-plus hours (11 years),

Infrared LEDs operate reliably year-after-year.

Photo diode:

A photodiode is a type of photodetector capable of converting light into either

current or voltage, depending upon the mode of operation.

Photodiodes are similar to regular semiconductor diodes except that they may be

either exposed (to detect vacuum UV or X-rays) or packaged with a window or optical

fibre connection to allow light to reach the sensitive part of the device. Many diodes

designed for use specifically as a photodiode will also use a PIN junction rather than the

typical PN junction.

Principle of operation

A photodiode is a PN junction or PIN structure. When a photon of sufficient

energy strikes the diode, it excites an electron thereby creating a mobile electron and a

positively charged electron hole. If the absorption occurs in the junction's depletion

region, or one diffusion length away from it, these carriers are swept from the junction by

the built-in field of the depletion region. Thus holes move toward the anode, and

electrons toward the cathode, and a photocurrent is produced.

Photovoltaic mode

When used in zero bias or photovoltaic mode, the flow of photocurrent out of the

device is restricted and a voltage builds up. The diode becomes forward biased and "dark

current" begins to flow across the junction in the direction opposite to the photocurrent.

This mode is responsible for the photovoltaic effect, which is the basis for solar cells—in

fact, a solar cell is just an array of large photodiodes.

Photoconductive mode

In this mode the diode is often (but not always) reverse biased. This increases the

width of the depletion layer, which decreases the junction's capacitance resulting in faster

response times. The reverse bias induces only a small amount of current (known as

saturation or back current) along its direction while the photocurrent remains virtually the

same.

Although this mode is faster, the photovoltaic mode tends to exhibit less

electronic noise. (The leakage current of a good PIN diode is so low – < 1nA – that the

Johnson–Nyquist noise of the load resistance in a typical circuit often dominates.)

Other modes of operation

Avalanche photodiodes have a similar structure to regular photodiodes, but they are

operated with much higher reverse bias. This allows each photo-generated carrier to be

multiplied by avalanche breakdown, resulting in internal gain within the photodiode,

which increases the effective responsivity of the device.

Phototransistors also consist of a photodiode with internal gain. A phototransistor is in

essence nothing more than a bipolar transistor that is encased in a transparent case so that

light can reach the base-collector junction. The electrons that are generated by photons in

the base-collector junction are injected into the base, and this current is amplified by the

transistor operation. Note that although phototransistors have a higher responsivity for

light they are unable to detect low levels of light any better than photodiodes.

Phototransistors also have slower response times.

Materials

The material used to make a photodiode is critical to defining its properties, because only

photons with sufficient energy to excite electrons across the material's bandgap will

produce significant photocurrents.

Materials commonly used to produce photodiodes include:

Material Wavelength range (nm)

Silicon 190–1100

Germanium 400–1700

Indium gallium arsenide 800–2600

Lead sulfide <1000-3500

Because of their greater bandgap, silicon-based photodiodes generate less noise

than germanium-based photodiodes, but germanium photodiodes must be used for

wavelengths longer than approximately 1 µm.

Since transistors and ICs are made of semiconductors, and contain P-N junctions,

almost every active component is potentially a photodiode. Many components, especially

those sensitive to small currents, will not work correctly if illuminated, due to the induced

photocurrents. In most components this is not desired, so they are placed in an opaque

housing. Since housings are not completely opaque to X-rays or other high energy

radiation, these can still cause many ICs to malfunction due to induced photo-currents.

Features

Critical performance parameters of a photodiode include:

Responsivity:

The ratio of generated photocurrent to incident light power, typically expressed in

A/W when used in photoconductive mode. The responsivity may also be

expressed as a quantum efficiency, or the ratio of the number of photogenerated

carriers to incident photons and thus a unitless quantity.

Dark current:

The current through the photodiode in the absence of light, when it is operated in

photoconductive mode. The dark current includes photocurrent generated by

background radiation and the saturation current of the semiconductor junction.

Dark current must be accounted for by calibration if a photodiode is used to make

an accurate optical power measurement, and it is also a source of noise when a

photodiode is used in an optical communication system.

Noise-equivalent power:

(NEP) The minimum input optical power to generate photocurrent, equal

to the rms noise current in a 1 hertz bandwidth. The related characteristic

detectivity (D) is the inverse of NEP, 1/NEP; and the specific detectivity () is the

detectivity normalized to the area (A) of the photodetector,. The NEP is roughly

the minimum detectable input power of a photodiode.

When a photodiode is used in an optical communication system, these parameters

contribute to the sensitivity of the optical receiver, which is the minimum input power

required for the receiver to achieve a specified bit error ratio.

Applications

Photodiode schematic symbol. P-N photodiodes are used in similar applications to other

photodetectors, such as photoconductors, charge-coupled devices, and photomultiplier

tubes.

Fig 31: Photo Diode

Photodiodes are used in consumer electronics devices such as compact disc players,

smoke detectors, and the receivers for remote controls in VCRs and televisions.

In other consumer items such as camera light meters, clock radios (the ones that dim the

display when it's dark) and street lights, photoconductors are often used rather than

photodiodes, although in principle either could be used.

Photodiodes are often used for accurate measurement of light intensity in science and

industry. They generally have a better, more linear response than photoconductors.

They are also widely used in various medical applications, such as detectors for

computed tomography (coupled with scintillates) or instruments to analyze samples

(immunoassay). They are also used in blood gas monitors.

PIN diodes are much faster and more sensitive than ordinary p-n junction diodes, and

hence are often used for optical communications and in lighting regulation.

P-N photodiodes are not used to measure extremely low light intensities. Instead, if high

sensitivity is needed, avalanche photodiodes, intensified charge-coupled devices or

photomultiplier tubes are used for applications such as astronomy , spectroscopy, night

vision equipment and laser range finding.

Circuit description:

In this project we required operating voltage for Microcontroller 89C51 is 5V.

Hence the 5V D.C. power supply is needed for the IC’s. This regulated 5V is generated

by stepping down the voltage from 230V to 18V now the step downed a.c voltage is

being rectified by the Bridge Rectifier using 1N4007 diodes. The rectified a.c voltage is

now filtered using a ‘C’ filter. Now the rectified, filtered D.C. voltage is fed to the

Voltage Regulator. This voltage regulator provides/allows us to have a Regulated

constant Voltage which is of +5V. The rectified; filtered and regulated voltage is again

filtered for ripples using an electrolytic capacitor 100μF. Now the output from this

section is fed to 40th pin of 89C51 microcontroller to supply operating voltage. The

microcontroller 89C51 with Pull up resistors at Port0 and crystal oscillator of 11.0592

MHz crystal in conjunction with couple of 30-33pf capacitors is placed at 18 th & 19th pins

of 89C51 to make it work (execute) properly. In our project we use IR sensors to detect

the presence of a vehicle. According to this project, 2 IR sensors are placed apart with a

fixed known distance. When ever IR rays are interrupted by a vehicle during first sensor

the count up timer is started. When the other IR sensor senses the presence of vehicle, the

count up timer is stopped. As the distance and time the IR receiver receives the IR signals

is noted by microcontroller and from that we need to calculate speed. Here speed is

calculated from the well known formula of speed which is distance/time.

CONCLUSION

The project “SPEED CHECKER FOR HI-WAYS” has been successfully designed and tested.

It has been developed by integrating features of all the hardware components

used. Presence of every module has been reasoned out and placed carefully thus

contributing to the best working of the unit.

Secondly, using highly advanced IC’s and with the help of growing technology

the project has been successfully implemented.

Finally we conclude that “SPEED CHECKER FOR HI-WAYS” is an emerging field

and there is a huge scope for research and development.

FUTURE ENHANCEMENT

We can enhance this project by using the technology like RF and increase the

distance to measure.

Bibliography

The 8051 Micro controller and Embedded Systems

- Janice Gillispie Mazidi

The 8051 Micro controller Architecture, Programming & Applications

-Kenneth J.Ayala

Fundamentals Of Micro processors and Micro computers

-B.Ram

Micro processor Architecture, Programming & Applications

-Ramesh S. Gaonkar

Electronic Components

-D.V. Prasad

Wireless Communications

- Theodore S. Rappaport

References on the Web:

www.national.com

www.atmel.com

www.microsoftsearch.com

www.geocities.com