Example Effect

Press the serial monitor, and you can see that the measured distance is 9.8cm-10.1cm with an error of about 0.2cm.

HC-SR04

An ultrasonic sensor used for distance measurement, widely applied in robotics to avoid obstacles and measure distances.

Its module uses Trig to trigger distance measurement,

which emits 8 40kHz square waves and automatically detects if there is a signal return.

If a signal is returned, it outputs a high level via echo, and the duration of the high level is twice the distance.

The formula is as follows:

Measuring Distance = (High Level Time * Speed of Sound) / 2

Main Technical Parameters

1: Operating Voltage: DC—5V 2: Static Current: less than 2mA 3: Output Level: High 5V 4: Output Level: Low 0V 5: Sensing Angle: not greater than 15 degrees 6: Detection Distance: 2cm-450cm 7: High Precision up to 0.2cm

BOM List

Arduino Uno *1

HC-SR04 Ultrasonic Sensor *1

Breadboard *1

Jumper Wires Several

Ruler *1

Obstacle *1

Pin Description: VCC — Supply 5V Power

TRIG — Trigger Control Signal Input

ECHO — Echo Signal Output and four other interface terminals

GND — Ground

Wiring Method

A relatively intuitive way:

Or refer to:

Program Implementation

Download the program for free: https://u16460183.ctfile.com/fs/16460183-295242528

#define Trig 2
#define Echo 3

float cm; 
float temp; 

void setup() {
  Serial.begin(9600);
  pinMode(Trig, OUTPUT);
  pinMode(Echo, INPUT);
}

void loop() {
  
  digitalWrite(Trig, LOW); 
  delayMicroseconds(2);    
digitalWrite(Trig,HIGH); 
  delayMicroseconds(10);    
digitalWrite(Trig, LOW); 

  temp = float(pulseIn(Echo, HIGH)); 
  
  cm = (temp * 17 )/1000; 

  Serial.print("Echo =");
  Serial.print(temp);
  Serial.print(" | | Distance = ");
  Serial.print(cm);
  Serial.println("cm");
  delay(100);
}