PIYUSH_K_SINGH
Published

Master Slave I2C Connection

How to Set up a MASTER-SLAVE connection between two Arduinos using I2C (Inter-Integrated Circuit) protocol.

BeginnerProtip39,933
Master Slave I2C Connection

Things used in this project

Hardware components

Arduino UNO
Arduino UNO
×1
Arduino UNO
Arduino UNO
×1
Jumper wires (generic)
Jumper wires (generic)
×1

Software apps and online services

Arduino IDE
Arduino IDE

Story

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Schematics

CIRCUIT_DIAG

Code

MASTER_CODE

C/C++
Upload to MASTER Arduino.
// Include the required Wire library for I2C<br>
#include<Wire.h>
int x = 0;
void setup() {
  // Start the I2C Bus as Master
  Wire.begin(); 
}
void loop() {
  Wire.beginTransmission(9); // transmit to device #9
  Wire.write(x);              // sends x 
  Wire.endTransmission();    // stop transmitting
  x++; // Increment x
  if (x > 5) x = 0; // `reset x once it gets 6
  delay(500);
}

SLAVE_CODE

C/C++
Upload to SLAVE Arduino.
// Include the required Wire library for I2C
#include <Wire.h>
int LED = 13;
int x = 0;
void setup() {
  // Define the LED pin as Output
  pinMode (LED, OUTPUT);
  // Start the I2C Bus as Slave on address 9
  Wire.begin(9); 
  // Attach a function to trigger when something is received.
  Wire.onReceive(receiveEvent);
}
void receiveEvent(int bytes) {
  x = Wire.read();    // read one character from the I2C
}
void loop() {
  //If value received is 0 blink LED for 200 ms
  if (x == 0) {
    digitalWrite(LED, HIGH);
    delay(200);
    digitalWrite(LED, LOW);
    delay(200);
  }
  //If value received is 3 blink LED for 400 ms
  if (x == 3) {
    digitalWrite(LED, HIGH);
    delay(400);
    digitalWrite(LED, LOW);
    delay(400);
  }
}

Credits

PIYUSH_K_SINGH

PIYUSH_K_SINGH

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Related channels and tags
  • Arduino
  • Communication