Waterproof Ultrasonic Range Distance Measurement Sensor SR04T

Applications

• Horizontal distance
• Obstacle avoidance, automatic control
• Object approaches, there is a perceived
• Traffic control
• Security, industrial control
• Artificial intelligence, and research

Specifications:

• Power supply :5V DC
• Quiescent current : 5mA
• Working current : 30mA
• Acoustic emission frequency: 40khz
• Effectual angle: <50°
• Sensing distance: 4.5m
• Blind distance: 25cm
• Resolution : 0.5 cm

There are 4 pins out of the module : VCC , Trig, Echo, GND. So it's a very easy interface for controller is to use it ranging. The process is: pull the Trig pin to high-level for more than 10us impulse , the module will start ranging ; finish ranging , If you find an object in front , Echo pin will be high level , and based on the different distance,it will take the different duration of high-level. So we can calculate the distance easily :

Distance = ((Duration of high level)*(Sonic :340m/s))/2
 

Wire connecting direct as following:

• 5V Supply
• Trigger Pulse Input
• Echo Pulse Output
• 0V Ground

Arduino Sketch

/*
 HC-SR04 Ping distance sensor:
 VCC to arduino 5v 
 GND to arduino GND
 Echo to Arduino pin 7 
 Trig to Arduino pin 8
 
 This sketch originates from Virtualmix: http://goo.gl/kJ8Gl
 Has been modified by Winkle ink here: http://winkleink.blogspot.com.au/2012/05/arduino-hc-sr04-ultrasonic-distance.html
 And modified further by ScottC here: http://arduinobasics.blogspot.com.au/2012/11/arduinobasics-hc-sr04-ultrasonic-sensor.html
 on 10 Nov 2012.
 */


#define echoPin 7 // Echo Pin
#define trigPin 8 // Trigger Pin
#define LEDPin 13 // Onboard LED

int maximumRange = 200; // Maximum range needed
int minimumRange = 0; // Minimum range needed
long duration, distance; // Duration used to calculate distance

void setup() {
   Serial.begin (9600);
   pinMode(trigPin, OUTPUT);
   pinMode(echoPin, INPUT);
   pinMode(LEDPin, OUTPUT); // Use LED indicator (if required)
}

void loop() {
  /* The following trigPin/echoPin cycle is used to determine the
   distance of the nearest object by bouncing soundwaves off of it. */ 
 digitalWrite(trigPin, LOW); 
 delayMicroseconds(2); 

 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10); 
 
 digitalWrite(trigPin, LOW);
 duration = pulseIn(echoPin, HIGH);
 
 //Calculate the distance (in cm) based on the speed of sound.
 distance = duration/58.2;
 
 if (distance >= maximumRange || distance <= minimumRange){
   /* Send a negative number to computer and Turn LED ON 
   to indicate "out of range" */
   Serial.println("-1");
   digitalWrite(LEDPin, HIGH); 
 } else {
   /* Send the distance to the computer using Serial protocol, and
   turn LED OFF to indicate successful reading. */
   Serial.println(distance);
   digitalWrite(LEDPin, LOW); 
 }
 
 //Delay 50ms before next reading.
 delay(50);
}