Difference between revisions of "SF-SR02 Ultrasonic Module"

Latest revision as of 08:31, 15 March 2017

Introduction

This module contains an ultrasonic sensor to detect the distance to an obstacle in front. It is usually used on robots to avoid obstacles. With the two holes, it can be installed easily on the robot. The sensor detects obstacles 2cm-700cm away, though it keeps stable signal output within 5m and the signals become weaker and weaker when it gets farther away from the obstacle beyond 5m.
There is power indicator light added onside to indicate power on/off. The 3-pin design makes it unique among most of the ultrasonic module in the market: the same pin to trigger and receive signals. The 3-pin anti-reverse cable included make the wiring tighter and more convenient. Also the beautiful cartoon design and the red PCB add to its fascination.
Note: Pin NSE is to burn firmware to the ship when it's manufactured and does not need to use later. If you hear some slight noise during the application, it's fine.

Feature

1) An ultrasonic module with a detecton range of 2cm-700cm; signals detected are stable within 5m, grow weaker beyond 5m and at last disappear
2) With a power indicator LED so you can tell whether it is powered
3) Auxiliary 3-pin anti-reverse cable, thus making the wiring tighter and convenient
4) Operating voltage: 5V; working current: 16mA
5) A cartoon shape with red PCB design, making it adorable and cute

Pin Function

GND: ground of the power
5V: 5V Supply
SIG: Trigger Pulse Input and Echo Pulse Output
NSE: No need to use; only used to burn the firmware to the chip when the module is manufactured.

Features

Test Code

/******************************************
 * Name:SF-SR02 Ultrasonic Module
 * Function:Detection the distance
For any technical questions, visit http://www.sunfounder.com/forum
 **********************************************/
//Email: service@sunfounder.com
//Website: www.sunfounder.com

#include <Wire.h>

#define SIG A0 //SIG attach to A0 of control board
unsigned long rxTime;
float distance;

void setup() 
{
  // put your setup code here, to run once:
  Serial.begin(115200);
}

void loop() {
  //set SIG as OUTPUT,start to output trigger signal to the module to start the ranging
  pinMode(SIG, OUTPUT);
  //Genarate a pulse 20uS pulse
  digitalWrite(SIG, HIGH);
  delayMicroseconds(20);
  digitalWrite(SIG, LOW);
  //set SIG as INPUT,start to read value from the module
  pinMode(SIG, INPUT);
  rxTime = pulseIn(SIG, HIGH);//waits for the pin SIG to go HIGH, starts timing, then waits for the pin to go LOW and stops timing
  //  Serial.print("rxTime:");
  //  Serial.println(rxTime);
  distance = (float)rxTime * 34 / 2000.0; //convert the time to distance
  //leave the distance between 2cm-800cm
  if(distance < 2)
  {
    distance=0;
  }
  if(distance > 800)
  {
    distance=0;
  }
  Serial.print("distance: "); //print distance: 
  Serial.print(distance); //print the distance
  Serial.println("CM"); //and the unit
  delay(10);
}

Resource

SF_SR02 Test Code
MAX232_DataSheet
SGM324YS14 datasheet