Example Code for Arduino-Range Measurement

Wiring Diagram

Other Preparation Work

If you have an Arduino board, you can simply connect the signal pin of SRF01 to a digital pin which have to defined as serial port,both TX/RX.

After you connect the sensor correctly, you can test the skecth below on your board.

Sample Code

/******************************************************************
* Arduino example for SRF01 and LCD03.                            *
* Takes a range in CM and displayes it on the LCD03 screen        *
* Both the SRF01 and the LCD0 use their own software serial port  *
*                                                                 *
* By James Henderson, 2012
* Modified by leff DFRobot
******************************************************************/

#include <SoftwareSerial.h>

#define SRF_TXRX         0x05                                       // Defines pin 5 to be used as RX and TX for SRF01
#define SRF_ADDRESS      0x01                                       // Address of the SFR01
#define GETSOFT          0x5D                                       // Byte to tell SRF01 we wish to read software version
#define GETRANGE         0x54                                       // Byte used to get range from SRF01
#define GETSTATUS        0x5F                                       // Byte used to get the status of the transducer

SoftwareSerial srf01 = SoftwareSerial(SRF_TXRX, SRF_TXRX);      // Sets up software serial port for the SRF01

void setup(){
  srf01.begin(9600);
  Serial.begin(9600);
  srf01.listen();                                         // Make sure that the SRF01 software serial port is listening for data as only one software serial port can listen at a time

  delay(200);                                             // Waits some time to make sure everything is powered up
  Serial.println("SRF01 Example");

  byte softVer;
  SRF01_Cmd(SRF_ADDRESS, GETSOFT);                        // Request the SRF01 software version
  while (srf01.available() < 1);
    softVer = srf01.read();                               // Read software version from SRF01

}

void loop(){
  byte hByte, lByte, statusByte, b1, b2, b3;

  SRF01_Cmd(SRF_ADDRESS, GETRANGE);                       // Get the SRF01 to perform a ranging and send the data back to the arduino
  while (srf01.available() < 2);
  hByte = srf01.read();                                   // Get high byte
  lByte = srf01.read();                                   // Get low byte
  int range = ((hByte<<8)+lByte);                         // Put them together

  Serial.println("Range = ");
  Serial.println(range, DEC);                                // Print range result to the screen
  Serial.println("  ");                                      // Print some spaces to the screen to make sure space direcly after the result is clear

  SRF01_Cmd(SRF_ADDRESS, GETSTATUS);                      // Request byte that will tell us if the transducer is locked or unlocked
  while (srf01.available() < 1);
    statusByte = srf01.read();                            // Reads the SRF01 status, The least significant bit tells us if it is locked or unlocked
  int newStatus = statusByte & 0x01;                      // Get status of lease significan bit
  if(newStatus == 0){

    Serial.println("Unlocked");                              // Prints the word unlocked followd by a couple of spaces to make sure space after has nothing in
  }
   else {

    Serial.println("Locked   ");                             // Prints the word locked followd by a couple of spaces to make sure that the space after has nothing in
  }

  delay(100);
}

void SRF01_Cmd(byte Address, byte cmd){               // Function to send commands to the SRF01
  pinMode(SRF_TXRX, OUTPUT);
  digitalWrite(SRF_TXRX, LOW);                        // Send a 2ms break to begin communications with the SRF01
  delay(2);
  digitalWrite(SRF_TXRX, HIGH);
  delay(1);
  srf01.write(Address);                               // Send the address of the SRF01
  srf01.write(cmd);                                   // Send commnd byte to SRF01
  pinMode(SRF_TXRX, INPUT);
  int availbleJunk = srf01.available();               // As RX and TX are the same pin it will have recieved the data we just sent out, as we dont want this we read it back and ignore it as junk before waiting for useful data to arrive
  for(int x = 0;  x < availbleJunk; x++) byte junk = srf01.read();
}

Result

The distance range could be tested from 0-600cm, 700cm is not very stable.