EEPROM read and write in Arduino - Mini Project: Build & Apply

EEPROM read and write

📖 Scenario: You are working on an Arduino project that needs to save a small number permanently, even when the power is off. This is useful for storing settings or counters that should not reset every time the board restarts.

🎯 Goal: Learn how to write a number to the Arduino's EEPROM memory and then read it back to use in your program.

📋 What You'll Learn

Create a variable to hold the number to save

Create a variable for the EEPROM address

Write the number to EEPROM at the given address

Read the number back from EEPROM

Print the read number to the Serial Monitor

💡 Why This Matters

🌍 Real World

Saving settings or counters that must stay even when the Arduino is turned off, like user preferences or device calibration data.

💼 Career

Understanding EEPROM read/write is important for embedded systems programming and IoT device development where persistent storage is needed.

1

Create the number and EEPROM address variables

Create an int variable called numberToSave and set it to 123. Also create an int variable called eepromAddress and set it to 0.

Arduino

# Create 'numberToSave' and 'eepromAddress' variables
// Your code here

Need a hint?

Use int numberToSave = 123; and int eepromAddress = 0; to create the variables.

2

Include EEPROM library and start Serial communication

Add #include <EEPROM.h> at the top. In setup(), start Serial communication at 9600 baud.

Arduino

#include 

int numberToSave = 123;
int eepromAddress = 0;

void setup() {
  Serial.begin(9600);
  // Your code here
}

void loop() {
  // Empty loop
}

Need a hint?

Remember to include the EEPROM library and start Serial in setup().

3

Write the number to EEPROM and read it back

In setup(), write numberToSave to EEPROM at eepromAddress using EEPROM.write(). Then read the value back into an int variable called readNumber using EEPROM.read().

Arduino

#include 

int numberToSave = 123;
int eepromAddress = 0;

void setup() {
  Serial.begin(9600);
  // Write numberToSave to EEPROM
  // Read value back into readNumber
  // Your code here
}

void loop() {
}

Need a hint?

Use EEPROM.write(address, value) to save and EEPROM.read(address) to read.

4

Print the read number to Serial Monitor

Add a Serial.println() statement in setup() to print the readNumber variable.

Arduino

#include 

int numberToSave = 123;
int eepromAddress = 0;

void setup() {
  Serial.begin(9600);
  EEPROM.write(eepromAddress, numberToSave);
  int readNumber = EEPROM.read(eepromAddress);
  // Print readNumber
  // Your code here
}

void loop() {
}

Need a hint?

Use Serial.println(readNumber); to show the saved number.