Connecting a Laser Distance Sensor to Arduino UNO – My Setup & Example Code

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I recently connected a LDJ Laser Distance Sensor to my Arduino UNO and wanted to share the simple wiring and sample code with fellow makers. This setup is ideal for anyone interested in precise distance measurement in projects like robotics, automation, or object detection.

LDJ laser distance sensor
LDJ laser distance sensor800×800 375 KB

:four_leaf_clover:What I Used:

  • Laser Distance Sensor (UART communication, 3.3V logic)
  • Arduino UNO R3
  • Jumper wires
  • Power via USB

Wiring Guide (as shown in the image):

Laser Sensor Wire Color Connection Arduino Pin
Black GND GND
Red 3.3V 3.3V
Yellow RX D3
Green TX D2

LDJ Laser Distance Measurement Sensor
LDJ Laser Distance Measurement Sensor1500×1500 142 KB

Note: Since Arduino UNO uses 5V logic and this sensor uses 3.3V, ensure your sensor can tolerate 5V signals on RX or use a voltage divider/logic level converter if needed.

Sample Arduino Code (Using SoftwareSerial):

#include <SoftwareSerial.h>

SoftwareSerial mySerial(2, 3); // RX, TX (Sensor TX -> D2, Sensor RX -> D3)

void setup() {
  Serial.begin(9600);
  mySerial.begin(115200); // Or the baud rate your sensor requires
  Serial.println("Laser Distance Sensor Initialized...");
}

void loop() {
  if (mySerial.available()) {
    while (mySerial.available()) {
      char c = mySerial.read();
      Serial.print(c);
    }
    Serial.println(); // Print a new line after each reading
  }

  delay(100); // Polling delay
}

Real Photo:

As shown in the image above, I used direct jumper wires to connect the module and Arduino. The wiring is clean and easy to reproduce.

Tips:

  • Make sure to check your sensor’s datasheet for proper voltage levels and serial baud rate.
  • You can visualize the distance readings using Serial Monitor (Ctrl+Shift+M in Arduino IDE).
  • Some sensors return binary data or need command requests — adapt the code accordingly.

Hope this helps you integrate a laser distance sensor into your next Arduino project!
Feel free to ask questions or share your own setup :blush:

2 Likes
2

I have moved this post to a more appropriate part of the forum. This is because you are not asking for advice, but giving an example of what you have done.

3

did you actually get it to work? I copied your code and I don't know how to test it

5

This line is false and misleading...

The line above that false printout simply started a SoftwareSerial communication link on pins 2 and 3 with the LASER peripheral, exactly like any two-way, serial comms. Speculating: If the xcvr was made ready when the Arduino came up, some form of handshaking probably occurred, because the xcvr looks more sophisticated than a bare LASER. Maybe it has the ability to change from steady light (for distance) to pulsed or PCM (pulse code modulation - used when you need to know YOUR return from another return, so you know which target is your's). The loop() function only receives character size data when present.

Find the technical document for the LDJ Laser Distance Sensor to understand what data is being received. (it might have a red, green or nearIR LED)