lOMoAR cPSD| 61371432
CS 1105 Unit 5 Assignment: Digital combination Lock Project
| Verified study complete Solutions | A+ Graded | 2026
Updated
Unit 5 Assignment Activity
Kyaw Zin Win
University of the People
CS 1105: Digital Electronics & Computer Architecture
Mopelola Akinyemi (Instructor)
October 7, 2025.
My Digital Electronics Project: A PLD-Based Combination Lock
For my introductory digital electronics project, I decided to design and build a simple
digital combination lock. My goal was to create a circuit that would only activate an output,
like turning on an LED, after a correct sequence of numbers was entered. I thought this would
be a great way for me to experiment with sequential logic and to understand the practical use
of a Programmable Logic Device (PLD). This project was my own attempt to apply the
concepts I learned from our course materials, and it gave me a much clearer understanding of
how these components work in a real application.
, lOMoAR cPSD| 61371432
2
Design of My Digital Circuit Project
The circuit I designed is a 3-digit sequential lock. The user has to enter the correct 2bit
binary numbers in the right order to "unlock" it. For my experiment, I chose the sequence 10
(2), 01 (1), and then 11 (3). The circuit has two data inputs for the 2-bit number, a button to
enter each number, a reset button, and a single LED output that lights up when the correct
sequence is entered.
My main idea was to build a state machine. The circuit starts in an initial "locked"
state. When I enter the first correct number (10) and press the enter button, the circuit moves
to a second state. From there, if I enter the next correct number (01), it moves to a third state.
Finally, entering the last correct number (11) moves it to the final "unlocked" state, which
turns on the LED. If I enter a wrong number at any point, the circuit resets back to the initial
locked state. This design felt challenging enough to be interesting but simple enough for me
to implement.
Component Identification and Explanation
To build my project, I realized I would need a few key components.
• Input Switches: I used two toggle switches to represent the 2-bit binary number. I
labeled them B1 (most significant bit) and B0 (least significant bit). By setting these
switches, I could create any number from 0 to 3 (binary 00 to 11).
• Enter and Reset Buttons: I included two pushbutton switches. The first is an "Enter"
button, which I connected to the clock input of my logic circuit. Every time I press it,
the circuit evaluates the number on the input switches and decides whether to change
CS 1105 Unit 5 Assignment: Digital combination Lock Project
| Verified study complete Solutions | A+ Graded | 2026
Updated
Unit 5 Assignment Activity
Kyaw Zin Win
University of the People
CS 1105: Digital Electronics & Computer Architecture
Mopelola Akinyemi (Instructor)
October 7, 2025.
My Digital Electronics Project: A PLD-Based Combination Lock
For my introductory digital electronics project, I decided to design and build a simple
digital combination lock. My goal was to create a circuit that would only activate an output,
like turning on an LED, after a correct sequence of numbers was entered. I thought this would
be a great way for me to experiment with sequential logic and to understand the practical use
of a Programmable Logic Device (PLD). This project was my own attempt to apply the
concepts I learned from our course materials, and it gave me a much clearer understanding of
how these components work in a real application.
, lOMoAR cPSD| 61371432
2
Design of My Digital Circuit Project
The circuit I designed is a 3-digit sequential lock. The user has to enter the correct 2bit
binary numbers in the right order to "unlock" it. For my experiment, I chose the sequence 10
(2), 01 (1), and then 11 (3). The circuit has two data inputs for the 2-bit number, a button to
enter each number, a reset button, and a single LED output that lights up when the correct
sequence is entered.
My main idea was to build a state machine. The circuit starts in an initial "locked"
state. When I enter the first correct number (10) and press the enter button, the circuit moves
to a second state. From there, if I enter the next correct number (01), it moves to a third state.
Finally, entering the last correct number (11) moves it to the final "unlocked" state, which
turns on the LED. If I enter a wrong number at any point, the circuit resets back to the initial
locked state. This design felt challenging enough to be interesting but simple enough for me
to implement.
Component Identification and Explanation
To build my project, I realized I would need a few key components.
• Input Switches: I used two toggle switches to represent the 2-bit binary number. I
labeled them B1 (most significant bit) and B0 (least significant bit). By setting these
switches, I could create any number from 0 to 3 (binary 00 to 11).
• Enter and Reset Buttons: I included two pushbutton switches. The first is an "Enter"
button, which I connected to the clock input of my logic circuit. Every time I press it,
the circuit evaluates the number on the input switches and decides whether to change
