Distance measurement with Arduino sensor HC-SR04 US-015
Presents sensors provide distance measurement using ultrasound. The sensor sends out a wave, which after reflection from the obstacle, it returns to him. Computing the time between transmission and reception of the pulse, we can determine the distance to the object.
We will need the following items:
Connect the sensor with Arduino:
The sensor using the Arduino you should connect the layout as follows:
| Pin BH1750 | Pin Arduino |
|---|---|
| VCC | 5 V |
| GND | GND |
| TRIG | 2 |
| ECHO |
3 |
Connection diagram of ultrasonic sensor with Arduino Uno.
Program for Arduino
In the example, we used the following code:
int Trig = 2; //pin 2 of Arduino is connected to the contact sensor Trigger
int Echo = 3; //Arduino pin 3 is connected to the contact sensor Echo
int CM; //distance in cm
long TIME; //duration of the reverse pulse in the uS
void setup()
{
Serial.begin(9600); //inicjalizaja monitor serial port
pinMode(Trig, OUTPUT); //setting Arduino pin 2 as output
pinMode(Echo, INPUT); //setting pin 3 in Arduino as input
Serial.println("Test of spacing");
}
void loop()
{
pomiar_odleglosci(); //measure the distance
Serial.print("Distance: "); //display results on the screen in a loop every 200 MS
Serial.print(CM);
Serial.println(" cm");
delay(200);
}
void pomiar_odleglosci ()
{
digitalWrite(Trig, LOW); //setting the high status on 2 uS pulse inicjalizujacy - see the documentation
delayMicroseconds(2);
digitalWrite(Trig, HIGH); //setting the high position for 10 uS pulse inicjalizujacy - see the documentation
delayMicroseconds(10);
digitalWrite(Trig, LOW);
digitalWrite(Echo, HIGH);
TIME = pulseIn(Echo, HIGH);
CM = DURATION / 58; //width of the reflected pulse in the uS divided by 58 is the distance in centimeters - see the documentation
}
To calculate the distance to the object, the response time is common to 58 (according to the documentation). Why so much? This value is derived by the formula:
TIME / [1/(0.34 / 2 )/10]
- the value in square brackets is equal to 58:
- 0.34 - wave velocity in m/MS (340 m/sec) divided by 2 (since the wave has come a long way in the two sides).
- In addition, all safely by 10 to change millimetres to centimeters
The result of the program can be viewed on the serial monitor:
A screenshot of the serial monitor.