The Institution of Engineers, NITK Chapter
IE ROBOTICS
The Institution of Engineers, NITK Chapter
IE ROBOTICS
The Institution of Engineers, NITK Chapter
The Institution of Engineers, NITK Chapter
Function What It Does
pinMode() Sets a pin as input or output
digitalWrite() Sends HIGH or LOW signal
digitalRead() Reads digital input (button, etc.)
analogRead() Reads analog value from A0–A5
analogWrite() Sends analog (PWM) signal
delay() Pauses the program
millis() Returns time (in ms) since start
Serial.begin() Starts serial communication
Serial.print() Prints text to Serial Monitor
The Institution of Engineers, NITK Chapter
A simple math quiz game built using Arduino.
Uses a 16x2 LCD and a 4x3 keypad interface.
Generates random math questions and checks user answers.
Score tracking and high score memory using EEPROM.
Includes buzzer sounds and reset functionality for real-time gameplay.
The Institution of Engineers, NITK Chapter
Arduino UNO
16x2 LCD Display
4x3 Matrix Keypad
Buzzer
Resistors & Wires
Breadboard
Potentiometer
Power Supply / USB cable
The Institution of Engineers, NITK Chapter
pin mappings:
LCD: RS->6, EN->5, D4->4, D5->3, D6->2, D7->1
Keypad Input Pins: 7, 8, 9, 10
Keypad Output Pins: 11, 12, 13
Reset Pin: A0
Buzzer: A1
The Institution of Engineers, NITK Chapter
→
Start Screen Press any key to start
Random math question appears
User enters answer using keypad
→
If correct +1 score & next question
→
If wrong or time exceeds 10s Game over
Displays final score and stores high score in EEPROM
The Institution of Engineers, NITK Chapter
LiquidCrystal.h
EEPROM.h
The Institution of Engineers, NITK Chapter
1. What is a 16x2 LCD?
A 16x2 LCD (Liquid Crystal Display) is a display module that can show 16
characters per line and has 2 such lines.
2. Modes of Operation
A. 8-bit Mode
Uses all D0–D7 data lines
Sends full byte at once
Rarely used to save pins
B. 4-bit Mode (common)
Uses only D4–D7
Sends data in two nibbles (4 bits at a time)
Saves pins, works perfectly for most projects
The Institution of Engineers, NITK Chapter
LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LCD Pin Arduino Pin What it Does
RS (Register Select) Pin 6 Tells the LCD if we are sending commands or data/text
Used to send data to the screen when it changes from LOW to
EN (Enable) Pin 5
HIGH
D4 Pin 4 Data pin to send bits (we're using 4-bit mode)
D5 Pin 3 Another data pin
D6 Pin 2 Another data pin
D7 Pin 1 Another data pin
**Arduino library supports 4-bit mode by default to keep things simple and save pins.
The Institution of Engineers, NITK Chapter
Important Functions in LiquidCrystal.h
Function What It Does
lcd.begin(16, 2) Initializes LCD with 16x2 display
lcd.print("text") Displays text
lcd.setCursor(col, row) Moves cursor to column & row
lcd.clear() Clears the display
lcd.blink() Makes cursor blink
lcd.noBlink() Stops blinking
lcd.cursor() Shows the cursor
lcd.noCursor() Hides the cursor
lcd.scrollDisplayLeft() Scrolls screen left
lcd.scrollDisplayRight() Scrolls screen right
The Institution of Engineers, NITK Chapter
1. Physical Structure
Matrix Configuration: 4 rows (R1–R4) and 4 columns (C1–C4)
Total Keys: 16 (4 rows × 4 columns)
2. How it works:
Microcontroller sets one row LOW at a time, others HIGH.
It reads all columns.
If a column is LOW, it means a button in that row and column intersection is
pressed.
Repeat for each row to identify exactly which button was pressed.
This method is called row-column scanning.
The Institution of Engineers, NITK Chapter
const int inputs[4] = {7, 8, 9, 10}; // Rows
const int outputs[3] = {11, 12, 13}; // Columns
Pin Type Pins Mode Why
Outputs 11, 12, 13 OUTPUT To activate one column at a time
To detect button press (goes LOW
Inputs 7, 8, 9, 10 INPUT_PULLUP
when pressed)
Arduino sets column pins LOW one by one
At the same time, it checks if any of the row pins go LOW
If pin 12 (column 1) is LOW and pin 8 (row 2) becomes LOW → you pressed ‘5’!
The Institution of Engineers, NITK Chapter
#define BUZZER A1
pinMode(BUZZER, OUTPUT);
You connect buzzer to A1
Then you use tone(BUZZER, frequency, duration) to make sound
noTone(BUZZER) stops sound
The Institution of Engineers, NITK Chapter
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