Digital Logic Design Project

1. i
Hurdle Race Game
Semester Project: Digital Logic Design
Course: BEE-4B
Teacher: Sir Arshad Nazir
Submitted by:
Student Name: Syed Maaz Imran
Complete Reg# NUST201200467BSEECS60412
Student Name: Muhammad Asawal
Complete Reg# NUST201200599BSEECS60412

2. Dedication
We dedicate this project to ourselves for the tireless efforts we have put in
throughout the design phase of this project. We set aside valuable time for this
project which could have been utilized for exam preparation, only to ensure a good
and finished product which will validate our learning of the subject and its practical
application.

3. Acknowledgements
First and foremost, we are thankful to Allah Almighty for the completion of this
project. Without whose help, we would not have been able to accomplish anything.
We also acknowledge the efforts of our Digital Logic Design instructor, Sir Arshad
Nazir, for teaching us the concepts of logic design in an excellent way and pushing us
to the limits to bring out the best in us. We also acknowledge his support through
the idea development phase of the project.
We are also thankful to lab engineer, Mr. Awais Waris, for helping us in learning the
simulation software Proteus and helping in debugging some errors during the
simulation phase.
We are also thankful to sources available on the internet which helped us out
whenever we got stuck during any phase of the project.

4. Abstract
3
Our Project is a hardware implemented game that incorporates a 4 * 7 matrix of LEDs
which display random patterns of 4 bit binary numbers cascading down the matrix. The
lighted LEDs are obstacles that need to be avoided by the player’s LED at the bottom.
The player’s LED has four possible positions to stay lighted which is controlled by two
push buttons by the user, shifting the LED left or right. Collisions of lighted LED obstacles
and the lighted player position is the loss of life for the player. Three such collisions cause
the game to be over. Each successful avoiding of collision increments the score by one.

5. 4
List of Figures:
Figure 1: Block Diagram ................................................................................................................................2
Figure 2: Detailed Circuit Diagram................................................................................................................2

6. 5
Table of Contents
Contents
Chapter 1: Introduction ................................................................................................................................ .1
1. Overview of Project .......................................................................................................................... .1
2. Block Diagram of Complete System (without using ICs, just use simple blocks)................... .............2
3. Clear Work Division................................................................................................................. ...........2
Chapter 2: Design....................................................................................................................... ....................3
1. Problem Statement.............................................................................................................. .............3
2. Solutions to Problems........................................................................................... .............. . . ...........3
3. Complete Logic Diagram.................................................................................... ................................7
Chapter 3: Hardware Implementation................................................................... ........................................8
1. Schematic Diagram .............................................................................. ..............................................8
2. Details of ICs used.............................................................................................................................9
3. Details of Other Components used like diodes, transistors, resistors etc........................................19
4. Hardware Issues / Results/ Observations...................................................................... ..................20
Chapter 4: Project Applications Further Suggestions (Optional)......................................... .......................21
Chapter 5: Future Recommendations................................................................................. .........................22
Bill of Materials.................................................................................................................... ........................23
References / Bibliography.................................................................................................. ..........................24

7. Chapter 1 Introduction
1
Chapter 1: Introduction
1.1 Overview of Project
Our Project is a game that comprises mostly a sequential circuit but with some
combinational parts as well. The number of inputs are two, both from the player,
namely right shift and left shift buttons, which the player will use to move his/her
position along the available row, avoiding the falling obstacles in the shape of glowing
red LEDs reaching the player’s green LED from above. If the player avoids the falling
obstacle successfully, his/her score is incremented by 1. Incase of collision with the
obstacle, one of the three lives of the player is lost. After three lives are lost, the game
is over, indicated by the game over LED. The game can then be reset and played again.

8. Chapter 1 Introduction
2
1.2 Block Diagram of Complete System (without using ICs, just use simple
blocks)
555 Timer ICs Random Pattern Shift Registers LEDs
Generating Circuit
Push Buttons Button Control Player LEDs Score
Circuit Counting &
Lives Control
Circuit
Figure 1: Block Diagram
1. Clear Work Division
Clearly describe the work of each and every member with the help of block diagram if possible. Or give a
new figure illustrating work division
Logic Development Software Implementation Hardware Implementation Documentation
Maaz – 80% Maaz – 20% Maaz – 40% Maaz – 60%
Asawal – 20% Asawal – 80% Asawal – 60% Asawal – 40%
Figure 2: Work Division

9. 3
Chapter 2 Design
Chapter 2: Design
2.1 Problem Statement
1. To develop a circuit to generate random four-bit numbers to light up a row of the LED
matrix.
2. To design a control circuit for the player to use left shift and right shift buttons and the
glowing LED shifting accordingly.
3. Checking the collision of the glowing player LED and the glowing obstacle LED on the last
row of the LED matrix.
4. To decrement the number of lives for each collision and increment the score for avoidance
of collision.
5. To propagate the four-bit binary number pattern for LEDs through the columns of the LED
matrix.
6. To keep a one row gap between each binary pattern for the player to move to a safer
position after each obstacle row.
7. To design a reset logic to stop the game after three lives are lost, and restart it on pressing
of the reset button.
8. To design a small circuit to display a four bit binary number as three LEDs, which turn off
one by one following each loss of life.
9. To avoid binary number (1111)2 as a row obstacle which makes the game impossible for the
player.
2.2 Solutions to Problems

10. 4
Chapter 2 Design
- Given above is our random number generation logic. The IC numbered 74163 is a four bit counter.
We have jumbled up its output sequence so that the number generation does not follow a pattern.
Hence solving problem statement 1.
- When the number (1111)2 is generated as output from the counter, we have used a four-input
NAND gate to give output zero for that number and used it input the IC’s active LOW load input
and also fed it into the Quad 2 to 1 MUX(74157) select line to select manually fed (0000)2 for the
LED matrix instead. Hence solving problem statement 9.
- We have used another Quad 2 to 1 MUX (74157) to select generated random number on positive
clock edge and select number (0000)2 on negative clock pulse by feeding clock signal into the
select line of the MUX. Hence solving problem statement 6.

11. 5
Chapter 2 Design
- We have used six universal shift registers (74194) in parallel loading mode in order to propagate
the obstacle pattern through our LED matrix, connecting the output of one register to the input of
the next. Hence solving problem statement 5.
- We have used an up/down counter (74193) to increment/decrement the position binary number
of the player through 4 possible states (00, 01, 10 and 11)2. Then we have used the output of the
counter as input to a Dual 2 to 4 line decoder (74155) which selects through the possible player
positions (0001, 0010, 0100, 1000)2 corresponding to the respective select line input from the
counter. Hence solving problem statement 2.
- The below AND gates are used to check collision on the bottom-most level of the LED matrix and
the second level NOR gate outputs 1 if any of the AND gate outputs is 1 (meaning collision has
occurred, and thus decrement lives count). The AND gate inputs at pins 2, 5, 10 and 13 are the
player LED positions and the inputs at pins 1, 4, 9 and 12 are the bottom most row of the LED

12. 6
Chapter 2 Design
matrix. The upper two level OR gates followed by the third level AND gate check if the collision was
avoided and thus increment score. Hence solving problem statement 4.
- The reset button is used as master reset to the clocks(using tristate buffers), to all the shift
registers, to the player control circuit, to the lives and score counting circuit. Hence solving
problem statement 7.
- The lives decrementing circuit (by counter IC 74193) is shown above. The least significant bit Q0
and Q1 will have values (11 for 3 lives, 10 for 2 lives, 01 for 1 life, 00 for game over). A simple logic
for all three life indicator LEDs is used, where the topmost LED will turn off as lives count goes
from (11)2 to (10)2 as AND gate output will become 0 as soon as one input is 0. The second LED will
turn off as soon as Q1 changes from 1 to 2, after loss of second life, and third LED will turn off
when both inputs are 0. A NOR gate also shown in the figure is used to hang the clocks (using tri
state buffers) when all three lives are lost. Hence solving problem statement 8.

13. 7
Chapter 2 Design
2.3 Complete Logic Diagram

14. 8
Chapter 3 Hardware Implementation
Chapter 3: Hardware Implementation
3.1 Detailed Schematic of Design and its Description
Draw the schematics of your design using Proteus or otherwise. Using the Pin numbering, IC
numbers. Give the numbers of ICs used as well. List all the components like resistors, diodes
etc.

15. 9
Chapter 3 Hardware Implementation
3.2 Details of ICs used
a. 74194 [4-bit Universal Shift Register]
Function Table
Schematic
b. 74163 [4-bit binary counter]
Function Table

16. 10
Chapter 3 Hardware Implementation
Schematic
c. 74157 [Quad 2 to 1 MUX]
Function Table
Schematic

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Chapter 3 Hardware Implementation
d. 74155 [Dual 2 to 4 line Decoder]
Function Table
Schematic
e. 74193 [4-bit Up/Down Counter]
Function Table

18. 12
Chapter 3 Hardware Implementation
Schematic
f. 7448 [BCD to 7-segment Decoder]
Function Table
Schematic

19. 13
Chapter 3 Hardware Implementation
g. 555 [Timer IC]
Function Table
Schematic
h. 74125 [Quad- Tristate Buffer]
Function Table

20. 14
Chapter 3 Hardware Implementation
Schematic
i. 7408 [Quad- Two input AND gate]
Function Table

21. 15
Chapter 3 Hardware Implementation
Schematic
j. 7432 [Quad- Two input OR gate]
Function Table

22. 16
Chapter 3 Hardware Implementation
Schematic
k. 7425 [Dual- 4 input NOR gate]
Function Table

23. 17
Chapter 3 Hardware Implementation
Schematic
l. 7404 [Hex- NOT gate]
Function Table

24. 18
Chapter 3 Hardware Implementation
Schematic
m. 7413 [Dual- 4 input NAND gate]
Function Table
Schematic

25. 19
Chapter 3 Hardware Implementation
3.3 Details of Other Components used like diodes, transistors, resistors
etc.
Capacitors:
10nF – 2 pieces
470uF – 1 piece
820uF – 1 piece
100uF – 1 piece
Resistors:
1 kohm – 4 pieces
100 ohm – 9 piece

26. 20
Chapter 3 Hardware Implementation
3.4 Hardware Issues / Results/ Observations
During hardware implementation, several issues were faced. After patching of
every block of the circuit, we used to test and debug our block for correct
results. The block worked correctly some times, other times it did not. We then
traced the error and removed it. Most of the times, the error was due to our our
human mistakes, however other times, some ICs would not perform their
functions properly and were replaced. The patching of the circuit took a lot of
time, and later when the circuit was working, we levitated the display to make
our project look more presentable.

27. 21
Chapter 4 Project Applications
Chapter 4: Project Applications
Our Project was a game, whose construction taught us a lot about Digital Logic Design in the most testing
ways possible. However practical applications of this project are limited. It can be used as a recreational
activity, as a cool gadget to show the practical applications of Digital Logic Design to new students.
However, the various blocks of our designed game can be individually used in the design of various other
components. The player control circuit block can be modified and used in simulating vehicle testing
machines.
Similarly, the random number propagation circuit can be modified to be used again in the vehicle design
simulator to be displayed as road traffic vehicles. The collision logic block may also be used here.

28. 22
Chapter 5 Future Recommendations
Chapter 5: Future Recommendations
Our Project can be improved and perhaps be implemented on PCBs instead of breadboards to reduce
hardware costs and the complexity look.
Perhaps a circuit can be added to increase the difficulty level of the game as a player progresses through.
It may even be split into a multiplayer mode to work as a scoring competition between two players.
Even a high-score saving capability can be added to be used in a storage element and displayed on
demand.

29. 23
Chapter 6 Bill of Materials
Bill of Materials
Give the bill of materials. Mention the IC name, cost and numbers of IC used. Mention the total cost of
project. Tabular form required.
Particulars Quantity Unit Price Amount
Breadboard 7 150 1050
Wires 15 m 10 150
Push button 4 20 80
7 segment CC Display 2 15 30
LM555 2 10 20
7448 2 45 90
74163 3 30 90
74193 5 30 150
74155 1 25 25
74157 2 25 50
74194 7 35 245
7408 2 20 40
7432 2 15 30
7404 2 15 30
7413 1 25 25
74125 1 30 30
Cap 470uF 1 5 5
Cap 820uF 1 5 5
Cap 100uF 1 5 5
Cap 10nF 2 2 4
Res 1kohm 2 0.5 1
Res 100ohm 10 0.5 5
LEDs 40 1 40
Net Total 2200

30. 24
Chapter 7 References
References / Bibliography
[www.datasheetarchive.com]
[www.google.com/images]
[www.google.com/web]