Laser Ranging Distance Sensor UART 4cm-4m Wiki - DFRobot

Introduction

This laser range sensor can be used to detect objects in 4~400cm with ±2cm accuracy. With 3 measurement modes supported, it is well applicable to various detection scenarios like security gate detection, access control systems, security alarm devices, smart trash cans, smart cars or robots for obstacle avoidance.
The sensor metal black shell adopts a threaded barrel design and its probe comes with an optical cover. The integrated design makes the product able to effectively filter optical interference, waterproof and shockproof. The sensor uses invisible laser and there is a voltage regulator circuit inside the module. Featuring stable performance and UART output, the sensor has an alarm output line that will be triggered to output Low steadily when the measurement distance is smaller than the user-set threshold.

Note: The data will be unstable when measuring black objects.

Specification

• Power Supply Voltage: 6-36V
• Measuring Distance: 4-400cm
• Measurement Accuracy: ±2cm
• Launch Angle: 39.6°
• Receiving Angle: 36.5°
• Working Current: <38mA
• Communication Interface: UART
• Waterproof Rating: IP67
• Baud Rate: 2400-921600 optional 115200 (default)
• Frequency: 20Hz (default)
• Working Temperature: -20~70°C
• Size: 21.5x21x8 mm / 0.85×0.83×0.31 inch

Dimension Figure

Board Overview

Tutorial

Requirements

• Hardware
  • Arduino UNO x 1
  • 6-in-1 multi-function to serial port module or FT232 USB to TTL Serial Cable
  • Laser Ranging Sensor UART 4m × 1

• Software
  • Arduino IDE

Usage for Arduino

Connection Diagram

Sample Code

#include <SoftwareSerial.h>
SoftwareSerial mySerial(12, 13); //Define soft serial port, port 13 is TX, port 12 is RX
uint8_t Data[34] = {0};

void setup()
{
  Serial.begin(115200);
  mySerial.begin(115200);
}


void loop()
{

  readData(Data);
  int Distance = readD(Data);
  if (Distance >= 0) {
    Serial.print("Distance: "); Serial.print(Distance); Serial.println(" mm");
    Serial.print("\n");
  } else {
    Serial.println("Invalid data");
    Serial.print("\n");
  }
  delay(500);
}

int readD(uint8_t *buf)
{
  int d;
  char *p = strstr(buf, "Range Valid");
  if (p != 0) {
    d = atoi(&Data[25]);
    return d;
  } else {
    return -1;
  }
}

void readData(uint8_t *buf)
{
  bool flag = 0;
  uint8_t ch;
  while (!flag) {
    if (readN(&ch, 1) == 1) {
      if (ch == 'S') {
        Data[0] = ch;
        if (readN(&ch, 1) == 1) {
          if (ch == 't') {
            Data[1] = ch;
            if (readN(&ch, 1) == 1) {
              if (ch == 'a') {
                Data[2] = ch;
                if (readN(&Data[3], 30) == 30 && Data[31] == 'm' && Data[32] == 'm') {
                  flag = 1;
                }
              }
            }
          }
        }
      }
    }
  }
}
int readN(uint8_t *buf, size_t len)
{
  size_t offset = 0, left = len;
  long curr = millis();
  while (left) {
    if (mySerial.available()) {
      buf[offset++] = mySerial.read();
      left--;
    }
    if (millis() - curr > 500) {
      break;
    }
  }
  return offset;
}

Usage for Serial Port Assistant

Connection Diagram

Turn the mode of 6-in-1 multi-function to serial port module to USB to TTL, as shown below:

Mode	Dial code 1 (USB)	Dial code 2 (485)	Switch S1	Diagram
USB to TTL	ON	OFF	Down (232-485)

Connect the sensor to 6-in-1 multi-function module, then plug the module into the usb port of computer, open the serial assistant, select Baud rate 1152000, untick HEX display and open the serial port, it will directly output distance value as shown below.

Register Table

FAQ

For any questions, advice or cool ideas to share, please visit the DFRobot Forum. If you have any questions about using this product, please check the FAQ list for that product for a corresponding solution.

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