Hi everybody,
I need some help with a project.
I want simply to check out the distance between the sensor SRF02 and some stuff.
The Problem is that my serial monitor shows 0cm the whole time (see picture). I have programmed the arduino with the standard Arduino Software and took the following code (found and simply modificated on: http://arduino.cc/en/Tutorial/SFRRangerReader)
#include <Wire.h>
void setup()
{
Wire.begin(); // join i2c bus (address optional for master)
Serial.begin(9600); // start serial communication at 9600bps
Serial.println("Arduino SRF02 Ultrasonic range finder \n ---------------------------------------");
delay(2000);
}
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(0x51)); // 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
}
if(reading >= 100){ // over 100 cm
Serial.println("Target out of Range.");
}
else{ // below 100 cm
Serial.print("Target in Range! (");
Serial.print(reading); // print distance
Serial.println("cm)");
}
delay(250); // wait a bit since people have to read the output :)
}
I choose the right board and the right baud rate.
Can anyboy help me?
