Search wiring.org.co:

This example is for Wiring version 1.0 build 0100+. If you have a previous version, use the examples included with your software. If you see any errors or have comments, please let us know.

I2C SRF10 or SRF08 Devantech Ultrasonic Ranger Finder by Nicholas Zambetti and James Tichenor
Demonstrates use of the Wire library reading data from the Devantech Utrasonic Rangers SFR08 and SFR10 On Wiring v1 boards the SCL and SDA pins are: 0 and 1 On Wiring S board the SCL and SDA pins are: 8 and 9

    #include <Wire.h>

    void setup()
    {
      Wire.begin();        // join i2c bus (address optional for master)
      Serial.begin(9600);  // start serial communication at 9600bps
    }

    int reading = 0;

    void loop()
    {
      // step 1: instruct sensor to read echoes
      Wire.beginTransmission(112);  // transmit to device #112 (0x70)
      // the address specified in the datasheet is 224 (0xE0)
      // but i2c adressing uses the high 7 bits so it's 112
      Wire.write((byte)0x00);       // sets register pointer to the command register (0x00)
      Wire.write((byte)0x50);       // command sensor to measure in "inches" (0x50)
      // use 0x51 for centimeters
      // use 0x52 for ping microseconds
      Wire.endTransmission();       // stop transmitting

      // step 2: wait for readings to happen
      delay(70);                    // datasheet suggests at least 65 milliseconds

      // step 3: instruct sensor to return a particular echo reading
      Wire.beginTransmission(112);  // transmit to device #112
      Wire.write((byte)0x02);             // sets register pointer to echo #1 register (0x02)
      Wire.endTransmission();       // stop transmitting

      // step 4: request reading from sensor
      Wire.requestFrom(112, 2);     // request 2 bytes from slave device #112

        // step 5: receive reading from sensor
      if (2 <= Wire.available())     // if two bytes were received
      {
        reading = Wire.read();      // receive high byte (overwrites previous reading)
        reading = reading << 8;     // shift high byte to be high 8 bits
        reading |= Wire.read();     // receive low byte as lower 8 bits
        Serial.println(reading);    // print the reading
      }

      delay(250);                   // wait a bit since people have to read the output :)
    }

    /*

     // The following code changes the address of a Devantech Ultrasonic Range Finder (SRF10 or SRF08)
     // usage: changeAddress(0x70, 0xE6);

     void changeAddress(byte oldAddress, byte newAddress)
     {
     Wire.beginTransmission(oldAddress);
     Wire.write(byte(0x00));
     Wire.write(byte(0xA0));
     Wire.endTransmission();

     Wire.beginTransmission(oldAddress);
     Wire.write(byte(0x00));
     Wire.write(byte(0xAA));
     Wire.endTransmission();

     Wire.beginTransmission(oldAddress);
     Wire.write(byte(0x00));
     Wire.write(byte(0xA5));
     Wire.endTransmission();

     Wire.beginTransmission(oldAddress);
     Wire.write(byte(0x00));
     Wire.write(newAddress);
     Wire.endTransmission();
     }

     */