1  // Wire Slave Sender
 2  // by Nicholas Zambetti <http://www.zambetti.com>
 3  
 4  // Demonstrates use of the Wire library
 5  // Sends data as an I2C/TWI slave device
 6  // Refer to the "Wire Master Reader" example for use with this
 7  
 8  // Created 29 March 2006
 9  
10  // This example code is in the public domain.
11  
12  
13  #include <Wire.h>
14  
15  void setup()
16  {
17    Wire.begin(2);                // join i2c bus with address #2
18    Wire.onRequest(requestEvent); // register event
19  }
20  
21  void loop()
22  {
23    delay(100);
24  }
25  
26  // function that executes whenever data is requested by master
27  // this function is registered as an event, see setup()
28  void requestEvent()
29  {
30    Wire.write("hello "); // respond with message of 6 bytes
31    // as expected by master
32  }