Reading I2C sensor data in Arduino - Mini Project: Build & Apply

Reading I2C sensor data

📖 Scenario: You have a temperature sensor connected to your Arduino using the I2C communication protocol. You want to read the temperature data from the sensor and display it on the Serial Monitor.

🎯 Goal: Build a simple Arduino program that reads temperature data from an I2C sensor and prints the temperature value to the Serial Monitor.

📋 What You'll Learn

Use the Wire library to communicate over I2C

Initialize the I2C communication in the setup() function

Read two bytes of data from the sensor at I2C address 0x48

Combine the two bytes into a temperature value

Print the temperature value to the Serial Monitor

💡 Why This Matters

🌍 Real World

Reading sensor data over I2C is common in projects like weather stations, home automation, and robotics.

💼 Career

Understanding I2C communication and sensor data reading is essential for embedded systems and hardware programming jobs.

1

Setup I2C communication and sensor address

Include the Wire.h library and create a constant byte variable called sensorAddress with the value 0x48.

Arduino

# Include the Wire library and define sensorAddress
// Your code here

Hint

Use #include <Wire.h> to include the I2C library. Define sensorAddress as const byte sensorAddress = 0x48;.

2

Initialize I2C and Serial communication

In the setup() function, start the I2C communication with Wire.begin() and start Serial communication at 9600 baud with Serial.begin(9600).

Arduino

#include 
const byte sensorAddress = 0x48;

void setup() {
  // Initialize I2C and Serial communication
  // Your code here
}

void loop() {
  // Your code here
}

Hint

Use Wire.begin() to start I2C and Serial.begin(9600) to start serial communication.

3

Read two bytes from the sensor

In the loop() function, request 2 bytes from the sensor using Wire.requestFrom(sensorAddress, 2). Then read the first byte into highByte and the second byte into lowByte using Wire.read().

Arduino

#include 
const byte sensorAddress = 0x48;

void setup() {
  Wire.begin();
  Serial.begin(9600);
}

void loop() {
  // Request 2 bytes from sensor
  // Read highByte and lowByte
  // Your code here
}

Hint

Use Wire.requestFrom(sensorAddress, 2) to ask for 2 bytes. Use Wire.read() twice to get each byte.

4

Calculate temperature and print it

Combine highByte and lowByte into an integer called temperature by shifting highByte 8 bits left and OR with lowByte. Then print "Temperature: " followed by temperature and " C" to the Serial Monitor.

Arduino

#include 
const byte sensorAddress = 0x48;

void setup() {
  Wire.begin();
  Serial.begin(9600);
}

void loop() {
  Wire.requestFrom(sensorAddress, 2);
  byte highByte = Wire.read();
  byte lowByte = Wire.read();

  // Calculate temperature and print
  // Your code here
}

Hint

Shift highByte left by 8 bits and OR with lowByte to get temperature. Use Serial.print and Serial.println to show the temperature.