EV3 and Arduino

A simple tutorial of how to communicate between the Arduino and the EV3, using I2C.

Requeriments

• Arduino.
• EV3.
• EV3 Cable.
• 2x - 40kΩ Resistor Pull-Up (Optional, if the a communication was with problems, use the resistors!).

EV3 and Arduino Pinout

• Analog - White.
• Ground - Black.
• Ground - Red.
• Vin - Green.
• I2C Clock - Yellow.
• I2C Data - Blue.

Library used:

• Wire: This library is used to do the communication using the I2C.

#include <Wire.h> 
#define SLAVE_ADDRESS 0x04 

void setup()
{
    Wire.begin(SLAVE_ADDRESS); 
    Wire.onReceive(readData); 
    Wire.onRequest(sendData); 
}

Send 1 byte to EV3

• Wire.write();: Send the byte.

Example:

void sendData()
{
  int s2 = 1;
  Wire.write(s2);
}

Send 8 bytes to EV3

• Wire.write();: Send the bytes.

Example:

void sendData()
{
  uint8_t s2[8] = {"1","2","3","4","5","6","7","8"};
  Wire.write(s2,8);
}

Read 1 byte on Arduino

• Wire.read();: Receive the byte.

Example:

void readData()
{
    while(Wire.available()>0)
    {
      s2 = Wire.read();
    }
}

Read 8 bytes on Arduino

• Wire.read();: Receive the bytes.

Example:

void readData()
{
    while(Wire.available()>0)
    {
      s2 = Wire.read();
      for (int i = 0; i < 7; i++) {
        Wire.read();
      }
    }
}

Address

• The address sent to Arduino is 0x04 or 4

Read 1 byte on EV3

Read 8 bytes on EV3

Send 1 byte to Arduino

Send 8 bytes to Arduino

Read Analog Pin on EV3

Send Digital Write to Arduino on EV3

Credits

• Alisson Silva