Difference between revisions of "Ultrasonic range measurement module"

Revision as of 00:49, 23 May 2012

Introduction

SRF-05 is the latest model of this series of ultrasonic distance measuring sensor.This ultrasonic ranger has an approximate range of 3 cm to 4 m. This ranger has a logic line used to trigger a pulse and the echo is returned on a second line. Minimal power requirements and a compact, self contained design make this a versatile range finder.

Description

• Working Voltage : 5V(DC)
• Static current: Less than 2mA.
• Output signal: Electric frequency signal, high level 5V, low level 0V.
• Sensor angle: Not more than 15 degrees.
• Detection distance: 2cm-450cm.
• High precision: Up to 0.3cm
• Input trigger signal: 10us TTL impulse
• Echo signal : output TTL PWL signal

Working principal

1.Adopt IO trigger through supplying at least 10us sequence of high level signal. 2.The module automatically send eight 40khz square wave and automatically detect whether receive the returning pulse signal. 3.If there is signals returning, through outputting high level and the time of high level continuing is the time of that from the ultrasonic transmitting to receiving. Test distance = (high level time * sound velocity (340M/S) / 2.

Usage

[User guide http://www.robot-electronics.co.uk/acatalog/Ultrasonic_Rangers.html]

Example code

      int inputPin=4;  // define ultrasonic signal receiver pin  ECHO to D4
      int outputPin=5; // define ultrasonic signal transmitter pin  TRIG to D5
      void setup()
      {
        Serial.begin(9600);
        pinMode(inputPin, INPUT);
        pinMode(outputPin, OUTPUT);
       }
     void loop()
    {
        digitalWrite(outputPin, LOW); 
        delayMicroseconds(2);
        digitalWrite(outputPin, HIGH); // Pulse for 10μs to trigger ultrasonic detection
        delayMicroseconds(10);
        digitalWrite(outputPin, LOW);   
        int distance = pulseIn(inputPin, HIGH);  // Read receiver pulse time
        distance= distance/58;   // Transform pulse time to distance
        Serial.println(distance);   //Ourput distance                 
        delay(50);   
     }

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