i2c_scanner.cpp

#include <Arduino.h>
#include <Wire.h>

void setup()
{
	Wire.begin(4, 5);

	Serial.begin(115200);
	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("  !");
			Wire.beginTransmission(address);
			Wire.write()

			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
}