View source for Ultrasonic range measurement module

==Introduction==

[[File:Ultra Sonic 1.jpg]]
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==
[[File:SRF principal.jpg]]

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==
[[File:Ultrasonic 2.jpg]]
[[File:Ultrasonic table.jpg]]
 
[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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