traffic light control system using 8085 microprocessor

MICRO PROCESSOR ASSIGN. PRESENTATION. - 2

Batch 5

OUR TOPIC IS:

TRAFFIC LIGHT CONTROL SYSTEM

We mean:

NEED FOR THE SYSTEM :

Traffic lightsstoplights/ traffic lamps/ traffic signals/ signal lights/ robots/ semaphore

signaling devices positioned at road intersections,

pedestrian crossings and other locations to control competing flows of traffic. Preventing accidents Improving safety Minimize travel time

ABOUT THE COLORS OF TRAFFIC LIGHT CONTROL

Traffic lights alternate the right of way of road users by displaying lights of a standard color (red, yellow/amber, and green)

By using a universal color code (and a precise sequence to enable comprehension by those who are color blind

SIGNAL FOR VEHICLE

SIGNAL FOR PEDESTRIAN

PROCESSOR USED:

8085 Microprocessor

WHY 8085?

Sufficient memory for the given scenario

Basic units to be interfaced are supported by 8085

Less complicated in the aspect of coding

Supports the necessary instruction sets

Simple and robust

5v Power Supply

8085 Microprocessor

7 Segment Display

LED Display

TIMER

INPUT

DISPLAYSWAITING TIME

OUTPUT SIGNAL

BASIC BLOCK DIAGRAM

BLOCK DIAGRAM:

ALGORITHMStart

Enable R1 and R2 to glow

Make G3 G4 G3 Right,G4 Right ,G3 Left and G4 Left to glow

Delay for some time

Enable R3 and R4 to glow

Make G1 G2 G1 Right,G2 Right ,G1 Left and G2 Left to glow

Delay for some time

Disable G1 Right,G2 Right ,G1 Left and G2 Left , thus allowing only G1 and G2 to glow

Delay for some time

Disable G3 Right,G4 Right ,G3 Left and G4 Left , thus allowing only G3 and G4 to glow

Delay for some time

In that time , allow the pedestrians in the suitable road to cross

Enable Y1,Y2 ,Y3, Y4 to glow

Delay for few seconds

In that time , allow the pedestrians in the suitable road to cross

Enable Y1,Y2 ,Y3, Y4 to glow

Delay for few seconds

Repeat from first

STATE DIAGRAM FOR TRAFFIC CONTROLER

 PROPOSED SYSTEM:

HARWARE DETAILS:

2 PARTS

•8085 Processor based system •Traffic Light Controller Interface board

IC’S USED:

8085 Micro processor

8255 PPI

8253 Timer

8279 Keyboard and Display Interface 

8255 PIN

INTERFACING WITH 8085:

I/O MAP:

8255 FOR TRAFFIC LIGHT :

MVI A, 80H : Initialize 8255, port A and port B

OUT 83H (CR) : in output mode START: MVI A, 09H OUT 80H (PA) : Send data on PA to glow R1

and R2 MVI A, E4H OUT 81H (PB) : Send data on PB to glow

G3 ,G4,G3R,G4R MVI A, 0CH OUT 82H (PB) : Send data on PC to glow G3

R ,G4L

MVI C, 28H : Load multiplier count for delay CALL DELAY : Call delay subroutine  MVI A, 09H OUT 80H (PA) : Send data on PA to glow R1 and

R2 MVI A, 24H OUT 81H (PB) : Send data on PB to glow G3 and

G4 MVI A, 00H OUT 82H (PB) : Send data on PC to disable G3

L ,G4L & Enable Pedestrian Crossing  MVI C, 28H : Load multiplier count for delay CALL DELAY : Call delay subroutine

MVI A, 12H OUT (81H) PA : Send data on Port A to glow Y1 and

Y2 OUT (81H) PB : Send data on port B to glow Y3 and

Y4 MVI C, 0AH : Load multiplier count for delay CALL DELAY : Call delay subroutine  MVI A, E4H OUT (80H) PA : Send data on port A to glow G1 and

G2,G1R,G2R MVI A, 09H OUT (81H) PB : Send data on port B to glow R3 and

R4 MVI C, 28H : Load multiplier count for delay MVI A, 03H OUT 82H (PB) : Send data on PC to glow G1 L ,G2L  CALL DELAY : Call delay subroutine

MVI A, E4H OUT (80H) PA : Send data on port A to glow G1 and

G2 MVI A, 09H OUT (81H) PB : Send data on port B to glow R3 and R4 MVI A, 00H OUT 82H (PB) : Send data on PC to disable G1 L

,G2L Enable Pedestrian Crossing  MVI C, 28H : Load multiplier count (40i?) for delay CALL DELAY : Call delay subroutine MVI A, 12H OUT PA : Send data on port A to glow Y1 and Y2 OUT PB : Send data on port B to glow Y3 and Y4 MVI C, 0AH : Load multiplier count (10i?) for delay CALL DELAY: Call delay subroutine JMP START

DELAY SUBROUTINE:

DELAY:

DCR C : Decrement counter  JNZ DELAY

RET : Return to main program 

LOGIC FOR PEDESTRIANS CROSSING

8279 DISPLAY INTERFACE

7 SEGMENT DISPLAY FOR TRAFFIC LIGHT- WORKING :

The processor initializes the look up table pointer. The look up table contains the format for the 7 segment display

SEGMENT CODES FOR COMMON CATHODE DISPLAY

LOOK UP TABLE FOR DIGITS 1-8:

The microprocessor sends the data to the latch

From the latch, the data is sent to 8279 Display Interface

It then stores the data in its 16 X 8 Internal RAM

WRITING TO RAM:

There are 6 seven segment displays in 8085 kitI 4 displays addressII 2 displays dataHere we make use of last two displays to interpret the waiting time in each signal

Hence we require a decoder to select among the two displays 

Since there are 6 displays, we require a 3X8 decoder(74138)

The inputs to these pins will be s1,s2,s0 of 8279

Output of decoder xx0 Left display xx1 Right Display

  Output to the seven segment displays will be from A3-

0 and B3-0 

ANALOG TO DIGITAL CONVERTOR This is required because 8085 will require

only +5V power supply

REFERENCES: rbinnovations.com

gobookee.net

seminarprojects.com

eprlabs.blogspot.com

Batch members

DINESH .S (11I309) MARIA JERIN .J (11I324) SARATHY .K (11I340) SRINIVASAN .R (11I347) SUBASH .S (11I348) MURALI KRISHNAN .P (12I469)

FINAL PRODUCT: