PROJECT REPORT

NETAJI SUBHAS INSTITUTE OF TECHNOLOGY

EC316 Microprocessor Lab PROJECT

BIRTHDAY CANDLES

Synopsis

Our project name is ‘Birthday Candles’. We made this project

using 8085 microprocessor. In this project we will blowout the

candles by just blowing air from our mouth onto the circuit board.

There will be random LEDs flickering when there’s no blowing. A

thermistor is used to detect the temperature change, and then

blocks of LEDs turn off depending on the change detected.

SUBMITTED BY:

RAHUL KUMAR AHIRWAR (131\EC\13)

SACHIN ROHILLA (147\EC\13)

PROJECT TITLE AND PARTNER DETAILS

Project Title: BIRTHDAY CANDLES

Student Details: The project was undertaken by:

1. Rahul Kumar Ahirwar (131/EC/13)

2. Sachin Rohilla (147/EC/13).

ACKNOWLEDGEMENT

To complete our project, we are very much thankful to our

Professor Dhananjay Gadre Sir for giving us this opportunity

and guidance throughout the project. We would also like to

thank our friends for their support and help in making the

project. This project was definitely a milestone in our career

and we learnt a lot more than just electronics, values of

hard work and team work.

We would also like to thank our friends and classmates

especially Vaibhav and Sahishnu who worked with us and

helped at each and every point of time we needed help and

assistance. From helping us learn EAGLE, guiding to get PCB

ready, helping us through the soldering sessions, getting

corrections in code and also final checks

On the project and what not, they were always with us. It

was a really good memorable experience working with all

of them.

We would also like to thank all the staff of the Department

of Electronics of Netaji Subhas Institute of Technology for

providing us with all the requisites for completion of this

project.

CONTENTS 1. INTRODUCTION

2. PROJECT DESCRIPTION

3. BLOCK DIAGRAM

4. PROGRAM FLOWCHART

5. PROGRAMMING CODE

6. WORKING

7. TESTING

8. MAKING OF BIRTHDAY CANDLES

9. SCHEMATIC DIAGRAM

10. BOARD FILE

11. GANTT CHART

12. CONCLUSION

13. BIBLIOGRAPHY

INTRODUCTION

The Intel 8085 microprocessor plays a significant role in the everyday

functioning of industrialized societies. The microprocessor is a

multipurpose, programmable, clock driven, register based electronic

device that reads binary instruction from a storage device called

memory, accepts binary data as input, and processes data according to

those instructions and provides results as output.

Intel 8085 is an ideal microprocessor for the purpose of introducing

students with the vast subject of microprocessors. We were inspired to

make a project whereby we can use all the features of Intel 8085 and use

it to create an exciting project.

Our project is LED based birthday candles with the feature to blow out

continuously monitored by the microprocessor. Every year, many

candles are used on birthday occasion. Therefore we can replace it with

microprocessor based birthday candles.

PROJECT DESCRIPTION

The objective of the project is to design LED based birthday candles

with the feature to blow out continuously monitored by the

microprocessor. When a person blows air on the thermistor, it cools

down and this reduces the voltage at the resistor junction. If the

voltage drop is more than a certain preprogrammed threshold, the

microprocessor starts putting off LEDs in a random sequence.

Various components are used in making the project which are

mentioned below:

1.8085 microprocessor

2. RAM 62256

3. EEPROM 28256

4. Decoder 74138

5. NOR Gate IC 7402

6. Latches 745273

7. ADC 0804

8. LED’s

9. Resistor and Capacitors

10. Thermistor

11. Push buttons

12. LC CRYSTAL AND USB PORT

BLOCK DIAGRAM

LED(16)

PROGRAM FLOWCHART

RESET THE uP

LIGHT ALL LEDs

Call 1 sec DELAY

INITIALISE COUNTER D

and MEMORY POINTER

HL

O/P VALUE IN MEMORY

POINTED BY HL AT 05H

PORT

INCREMENT HL

O/P VALUE IN MEMORY

POINTED BY HL AT 00H

PORT

INCREMENT HL

CALL 500 ms DELAY

DECREMENT COUNTER D

IF D=0 GO TO BLOW OFF

NO YES

INITIALISE COUNTER

AND HL MEMORY

POINTER

O/P SUM VALUE AT ADC

PORT 03

ENABLE INTERRUPT

ADC CONVERTS ANALOG

TO DIGITAL AND ISSUE

INTERRUPT RST 7.5

COMPARE DIGITAL O/P

WITH FIXED VALUE SET

O/P VALUE MEMORY

POINTED BY HL AT 05

PORT

INCREMENT HL

IS IT

LOWER

YES

NO

BLOW OFF

O/P VALUE IN MEMORY

POINTED BY HL AT O6 PORT

INCREMENT HL

CALL DELAY

DECREMENT COUNTER D

HALT

IS D=0?

NO YES

PROGRAMMING CODE //OSL1 0101-05H, OSL2 0110-06H, ADC CS 0011-03H

//LOOKUP FOR FLICKERING AND BLOW OFF

#ORG 2000H

#DB 55H,55H,99H,99H,2DH,4AH,A5H,A9H,25H,DAH,ADH,43H,A4H,B3H,17H,05H

#ORG 2100H

#DB 01H,10H,07H,70H,FFH,70H,FFH,FEH,FFH,FFH

//BEGIN AND SID SOD FUNCTION

#ORG 0000H

JMP BEGIN

#ORG 0100H

BEGIN:

LXI SP,9000H

MVI B,FFH

MVI C,64H

CALL DELAY //1 SEC DELAY

SID: DCR B

RIM

ANI 80H

JNZ SID //WHEN SID PIN GOES LOW, THEN IT EXITS LOOP

ORI C0H

SIM //SOD PIN GOES HIGH

//LIGHT ALL CANDLES

MVI A,00H

OUT 05H

OUT 06H

MVI C,64H

CALL DELAY

//FLICKERING RANDOM PATTERNS

MVI B,08H

LXI H, 2000H

LOOP:MOV A,M

OUT 05H

INX H

MOV A,M

OUT 06H

INX H

DCR B

MVI C,32H

CALL DELAY //500 ms delay,

JNZ LOOP

//BLOW OFF

MVI C,64H

CALL DELAY

MVI A,0BH

SIM

MVI D,05H

LXI H,2100H

ADC:OUT 03H

EI

JMP ADC

//IOW LOW AND CONVERSION STARTS, WHEN ENDS INTERRUPT ISSUED

#ORG 003CH

JMP 0300H

#ORG 0300H

IN 03H

CPI 89H

JC ADC // IF INPUT LESS THEN FIXED VALUE GO BACK

MOV A,M //LOOKUP OR RANDOM

OUT 05H

INX H

MOV A,M

OUT 06H

INX H

DCR D

JNZ ADC

DI

HLT

//DELAY ROUTINE

#ORG 0600H

DELAY: PUSH D

MVI D,06H

LOOP2DEL: MVI E,EDH

LOOP1DEL: DCR E

JNZ LOOP1DEL

DCR D

JNZ LOOP2DEL

DCR C

JNZ DELAY

POP D

RET

WORKING

The working of our project "BIRTHDAY CANDLES" is given below:

As we have mentioned earlier this project is based on the thermistor (which is a

temperature sensor).When power supply is given, all the LEDs start glowing ,then

after 1 second of delay these LEDs will start flickering in a random pattern(just like

candle does). Therefore power resistor starts heating which in turn heats the

thermistor.

When we blow the air onto the thermistor, it starts cooling down and ADC starts

the conversion. To start the conversion, the CS and WR signals goes asserted low,

the internal SAR (successive approximation register) is reset and the O/P lines

goes into the high impedance state. When WR makes the transition low to high,

the conversion begins. When the conversion is completed, the INTR is asserted

low and the data placed on the output lines. The INTR signal can be used to

interrupt the processor. When the processor reads the data by asserting RD, the

INTR is reset. And LED's go out randomly.

TESTING

Testing the Circuit Board, these steps were followed during the testing process:

1. A simple assembly language program was burnt in the EEPROM to check for

inputs on the SID pin and to throw the same as output on the SOD line.

RIM

ANI 80H

ORI 40H

SIM

The output on the SOD pin was indicated using a red LED. The working of this

program ensured smooth functioning of the 8085 and the EEPROM.

MAKING OF BIRTHDAY CANDLES

SCHEMATIC DIAGRAM

BOARD FILE

GANTT CHART

1-Jan 20-Feb 10-Apr 30-May 19-Jul

COMPLETE THE PATTERN

CHOOSE PARTNER

DECIDING PROJECT

GETTING APPROVED

STUDY OF 8085 DATASHEET

STUDY OF RAMESH GAONKAR

PREPARE SCHEMATIC

TESTING OF SCHEMATIC

PCB LAYOUT

PROGRAMMING

TESTING AND IMPROVEMENT

CONCLUSION

Our project “BIRTHDAY CANDLES” is not fully working. There might be

some problem in RAM.

This project would not have been possible without the motivation and

guidance from Professor Gadre. We would like to thank Sahishnu, Sachin

Demla and Vaibhav for the help and support.

BIBILOGRAPHY

BOOKS

GAONKAR, R. S., & GAONKAR, R. S. (1996). Microprocessor

architecture, programming, and applications with the 8085.

DATASHEETS

http://www.nxp.com/documents/data_sheet/74HC_HCT138.pdf

http://www.datasheetarchive.com/8085%20opcode-datasheet.html

www.ti.com/lit/ds/symlink/adc0808-n.pdf

https://8085simulator.codeplex.com.html