Example Code for Arduino-Distance Measurement

Hardware Preparation

• Arduino UNO
• UNO IO Sensor Expansion Board
• A01NYUB Ultrasonic Sensor
• 4P Connector

Software Preparation

• Arduino IDE (download from Arduino Official Website)
• SoftwareSerial library (included with Arduino IDE)

Wiring Diagram

Sample Code

/*
       @File  : DFRobot_Distance_A01.ino
       @Brief : This example use A01NYUB ultrasonic sensor to measure distance
                With initialization completed, We can get distance value
       @Copyright [DFRobot](https://www.dfrobot.com),2016
                  GUN Lesser General Pulic License
       @version V1.0
       @data  2019-8-28
*/

#include <SoftwareSerial.h>

SoftwareSerial mySerial(11, 10); // RX, TX
unsigned char data[4] = {};
float distance;

void setup()
{
  Serial.begin(57600);
  mySerial.begin(9600);
}

void loop()
{
  do {
    for (int i = 0; i < 4; i++)
    {
      data[i] = mySerial.read();
    }
  } while (mySerial.read() == 0xff);

  mySerial.flush();

  if (data[0] == 0xff)
  {
    int sum;
    sum = (data[0] + data[1] + data[2]) & 0x00FF;
    if (sum == data[3])
    {
      distance = (data[1] << 8) + data[2];
      if (distance > 280)
      {
        Serial.print("distance=");
        Serial.print(distance / 10);
        Serial.println("cm");
      } else
      {
        Serial.println("Below the lower limit");
      }
    } else Serial.println("ERROR");
  }
  delay(150);
}

Result

• When the measured distance is above 28cm, the serial monitor will output "distance=X cm" (X is the measured distance in centimeters).
• When the measured distance is below 28cm, the serial monitor will output "Below the lower limit".
• If the checksum is incorrect, the serial monitor will output "ERROR".