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// I2C SRF10 or SRF08 Devantech Ultrasonic Ranger Finder
// by Nicholas Zambetti <http://www.zambetti.com>
// and James Tichenor <http://www.jamestichenor.net>
// Demonstrates use of the Wire library reading data from the
// Devantech Utrasonic Rangers SFR08 and SFR10
// Created 29 April 2006
#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.send(0x00); // sets register pointer to the command register (0x00)
Wire.send(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.send(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.receive(); // receive high byte (overwrites previous reading)
reading = reading << 8; // shift high byte to be high 8 bits
reading |= Wire.receive(); // 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.send(0x00);
Wire.send(0xA0);
Wire.endTransmission();
Wire.beginTransmission(oldAddress);
Wire.send(0x00);
Wire.send(0xAA);
Wire.endTransmission();
Wire.beginTransmission(oldAddress);
Wire.send(0x00);
Wire.send(0xA5);
Wire.endTransmission();
Wire.beginTransmission(oldAddress);
Wire.send(0x00);
Wire.send(newAddress);
Wire.endTransmission();
}
*/
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