// i2c_scanner
// Version 1
//    This program (or code that looks like it)
//    can be found in many places.
//    For example on the Arduino.cc forum.
//    The original author is not know.
// Version 2, Juni 2012, Using Arduino 1.0.1
//     Adapted to be as simple as possible by Arduino.cc user Krodal
// Version 3, Feb 26  2013
//    V3 by louarnold
// Version 4, March 3, 2013, Using Arduino 1.0.3
//    by Arduino.cc user Krodal.
//    Changes by louarnold removed.
//    Scanning addresses changed from 0...127 to 1...119,
//    according to the i2c scanner by Nick Gammon
//    http://www.gammon.com.au/forum/?id=10896
// Version 5, March 28, 2013
//    As version 4, but address scans now to 127.
//    A sensor seems to use address 120.
// Version 6, November 27, 2015.
//    Added waiting for the Leonardo serial communication.
//
// This sketch tests the standard 7-bit addresses
// Devices with higher bit address might not be seen properly.
#include <Wire.h>
 
void setup() {
    Wire.begin();
    Serial.begin(9600);
    while (!Serial);    // Leonardo: wait for serial monitor
    Serial.println("\nI2C Scanner");
}
 
void loop() {
    byte error, address;
    int nDevices;
    Serial.println("Scanning...");
    nDevices = 0;
    for (address = 1; address < 127; address++) {
        // The i2c_scanner uses the return value of
        // the Write.endTransmisstion to see if
        // a device did acknowledge to the address.
        Wire.beginTransmission(address);
        error = Wire.endTransmission();
        if (error == 0) {
            Serial.print("I2C device found at address 0x");
            if (address<16)
                Serial.print("0");
                Serial.print(address,HEX);
                Serial.println("  !");
                nDevices++;
        } else if (error==4) {
            Serial.print("Unknown error at address 0x");
            if (address<16)
                Serial.print("0");
                Serial.println(address,HEX);
        }    
    }
    if (nDevices == 0)
        Serial.println("No I2C devices found\n");
    else
        Serial.println("done\n");

    delay(5000); // wait 5 seconds for next scan
}