LCD cursor positioning in Arduino

Introduction

We use LCD cursor positioning to control where text appears on the screen. It helps us show messages clearly and neatly.

You want to write text at a specific place on the LCD screen.

You need to update only part of the display without clearing everything.

You want to create menus or forms that look organized.

You want to show data like scores or time in fixed positions.

Syntax

Arduino

lcd.setCursor(column, row);

column starts at 0 for the leftmost position.

row starts at 0 for the top line.

Examples

This moves the cursor to the first column of the first row.

Arduino

lcd.setCursor(0, 0); // Top-left corner

This moves the cursor to column 5 (counting from 0) on the second row.

Arduino

lcd.setCursor(5, 1); // Sixth column, second row

Sample Program

This program shows how to position the cursor on a 16x2 LCD. It prints "Hello, World!" on the top line and "LCD Cursor Pos" on the bottom line.

Arduino

#include <LiquidCrystal.h>

// Initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
  lcd.begin(16, 2); // Set up the LCD's number of columns and rows
  lcd.setCursor(0, 0); // Move cursor to first column, first row
  lcd.print("Hello, World!");
  lcd.setCursor(0, 1); // Move cursor to first column, second row
  lcd.print("LCD Cursor Pos");
}

void loop() {
  // Nothing here
}

Important Notes

If you set the cursor outside the LCD size, text may not show or wrap unexpectedly.

Remember columns and rows start counting from zero, not one.

Summary

Use lcd.setCursor(column, row) to move the cursor.

Columns and rows start at zero.

Positioning helps organize text on the LCD screen.

Practice

1. What does the Arduino command lcd.setCursor(0, 1) do on a 16x2 LCD?

easy

A. Clears the LCD screen

B. Moves the cursor to the second column of the first row

C. Moves the cursor to the first column of the second row

D. Prints text at the current cursor position

Solution

1. Step 1: Understand lcd.setCursor parameters

   The first number is the column (starting at 0), the second is the row (starting at 0).

2. Step 2: Apply to given command

   lcd.setCursor(0, 1) moves the cursor to column 0 (first column) and row 1 (second row).

3. Final Answer:

   Moves the cursor to the first column of the second row -> Option C

4. Quick Check:

   Columns and rows start at zero = first column, second row [OK]

Hint: Remember columns and rows start at zero [OK]

Common Mistakes:

• Thinking rows start at 1 instead of 0
• Confusing column and row order
• Assuming setCursor prints text

2. Which of the following is the correct syntax to set the cursor to the third column and first row on an LCD?

easy

A. lcd.setCursor(3, 1);

B. lcd.setCursor(1, 2);

C. lcd.setCursor(0, 3);

D. lcd.setCursor(2, 0);

Solution

1. Step 1: Recall zero-based indexing

   Columns and rows start at 0, so third column is 2, first row is 0.

2. Step 2: Match parameters to correct syntax

   lcd.setCursor(2, 0) sets cursor to third column, first row.

3. Final Answer:

   lcd.setCursor(2, 0); -> Option D

4. Quick Check:

   Third column = 2, first row = 0 [OK]

Hint: Count columns and rows from zero [OK]

Common Mistakes:

• Using 1-based indexing for columns or rows
• Swapping column and row values
• Missing semicolon at end

3. What will be the output on a 16x2 LCD after running this code?

lcd.setCursor(5, 0);
lcd.print("Hi");
lcd.setCursor(0, 1);
lcd.print("Bye");

medium

A. First row: 'Hi' starting at first column, second row: 'Bye' starting at first column

B. First row: ' Hi' (5 spaces then Hi), second row: 'Bye' starting at first column

C. First row: 'Hi' starting at sixth column, second row: 'Bye' starting at sixth column

D. First row: ' Hi' (5 spaces then Hi), second row: ' Bye' (5 spaces then Bye)

Solution

1. Step 1: Analyze first setCursor and print

   lcd.setCursor(5, 0) moves cursor to column 5, row 0. Printing "Hi" starts at column 5 on first row.

2. Step 2: Analyze second setCursor and print

   lcd.setCursor(0, 1) moves cursor to first column, second row. Printing "Bye" starts there.

3. Final Answer:

   First row: ' Hi' (5 spaces then Hi), second row: 'Bye' starting at first column -> Option B

4. Quick Check:

   Cursor moves control print position [OK]

Hint: Cursor sets exact print start position [OK]

Common Mistakes:

• Assuming print always starts at first column
• Confusing row and column numbers
• Ignoring spaces before printed text

4. Identify the error in this Arduino code snippet for LCD cursor positioning:

lcd.setCursor(16, 0);
lcd.print("Hello");

medium

A. Column index 16 is out of range for a 16-column LCD

B. Row index 0 is invalid, should start at 1

C. Missing lcd.begin() before setCursor

D. lcd.print() cannot print strings

Solution

1. Step 1: Check column index range

   Columns start at 0, so valid columns are 0 to 15 for a 16-column LCD. 16 is out of range.

2. Step 2: Verify other parts

   Row 0 is valid (rows start at 0). lcd.print() can print strings. lcd.begin() is needed but not shown here, but question focuses on cursor.

3. Final Answer:

   Column index 16 is out of range for a 16-column LCD -> Option A

4. Quick Check:

   Column max index = 15 for 16 columns [OK]

Hint: Columns max at size minus one [OK]

Common Mistakes:

• Using 1-based indexing for columns
• Assuming lcd.print can't print strings
• Ignoring lcd.begin() requirement

5. You want to display a 4-letter word centered on the second row of a 20x4 LCD. Which lcd.setCursor() command correctly positions the cursor before printing?

hard

A. lcd.setCursor(8, 1);

B. lcd.setCursor(9, 1);

C. lcd.setCursor(7, 1);

D. lcd.setCursor(10, 1);

Solution

1. Step 1: Calculate center position for 4 letters on 20 columns

   Center column is 20 / 2 = 10. For 4 letters, start at 10 - (4 / 2) = 8.

2. Step 2: Set cursor to column 8 on second row

   Row 1 is second row (rows start at 0). So lcd.setCursor(8, 1) is correct.

3. Final Answer:

   lcd.setCursor(8, 1); -> Option A

4. Quick Check:

   Center start = half width minus half word length [OK]

Hint: Center = (width/2) - (word length/2) [OK]

Common Mistakes:

• Using 1-based indexing for rows or columns
• Starting cursor too far left or right
• Confusing row and column numbers