Documentation

// LD1125H ASCII reader for Arduino Uno
// Wiring: UTX->D2, URX->D3, VCC->5V, GND->GND
// Frames look like:   mov, dis=1.23   or   occ, dis=0.85

#include <SoftwareSerial.h>
SoftwareSerial RadarSerial(2, 3); // RX, TX

String line;

void setup() {
  Serial.begin(115200);
  RadarSerial.begin(115200);
  Serial.println("LD1125H reader ready");
}

void loop() {
  while (RadarSerial.available()) {
    char c = RadarSerial.read();
    if (c == '\n') {
      line.trim();
      if (line.length()) {
        if (line.startsWith("mov")) {
          Serial.print("MOVING  ");
        } else if (line.startsWith("occ")) {
          Serial.print("STATIC  ");
        } else {
          Serial.print(line);
          Serial.println();
          line = "";
          continue;
        }
        int eq = line.indexOf('=');
        if (eq > 0) Serial.print(line.substring(eq + 1));
        Serial.println(" m");
      }
      line = "";
    } else if (c != '\r') {
      line += c;
    }
  }
}

// LD1125H on ESP32 - ASCII reader + config helper
#include <HardwareSerial.h>
HardwareSerial RadarSerial(2);

String line;

void sendCmd(const String &cmd) {
  RadarSerial.print(cmd);
  RadarSerial.print("\r\n");
}

void setup() {
  Serial.begin(115200);
  RadarSerial.begin(115200, SERIAL_8N1, 16, 17);
  delay(500);
  // Example config: 6 m max, moderate sensitivity
  sendCmd("rmax=6");
  sendCmd("mth1=80");
  sendCmd("mth2=50");
  sendCmd("mth3=30");
  sendCmd("save");
  Serial.println("LD1125H ESP32 reader ready");
}

void loop() {
  while (RadarSerial.available()) {
    char c = RadarSerial.read();
    if (c == '\n') {
      line.trim();
      if (line.length()) {
        bool moving = line.startsWith("mov");
        bool stat   = line.startsWith("occ");
        int eq = line.indexOf('=');
        float d = (eq > 0) ? line.substring(eq + 1).toFloat() : -1;
        if (moving)      Serial.printf("MOVING  %.2f m\n", d);
        else if (stat)   Serial.printf("STATIC  %.2f m\n", d);
        else             Serial.println(line);
      }
      line = "";
    } else if (c != '\r') {
      line += c;
    }
  }
}

#!/usr/bin/env python3
"""LD1125H ASCII reader for Raspberry Pi."""
import serial, re, time

PORT = "/dev/serial0"
BAUD = 115200

ser = serial.Serial(PORT, BAUD, timeout=1)
print("LD1125H Pi reader started")

pattern = re.compile(r"^(mov|occ)\s*,\s*dis\s*=\s*([0-9.]+)", re.IGNORECASE)

def handle(state, distance_m):
    label = "MOVING" if state.lower() == "mov" else "STATIC"
    print(f"{label}  {distance_m:.2f} m")

while True:
    raw = ser.readline()
    if not raw:
        continue
    try:
        text = raw.decode("ascii", errors="ignore").strip()
    except UnicodeDecodeError:
        continue
    m = pattern.match(text)
    if m:
        handle(m.group(1), float(m.group(2)))

# LD1125H on Raspberry Pi Pico (MicroPython)
from machine import UART, Pin
import time

uart = UART(0, baudrate=115200, tx=Pin(0), rx=Pin(1))
buf = ""

print("LD1125H Pico reader ready")

while True:
    if uart.any():
        chunk = uart.read(uart.any())
        try:
            buf += chunk.decode("ascii")
        except UnicodeError:
            buf = ""
            continue
        while "\n" in buf:
            line, buf = buf.split("\n", 1)
            line = line.strip()
            if not line:
                continue
            if line.startswith("mov") or line.startswith("occ"):
                label = "MOVING" if line.startswith("mov") else "STATIC"
                eq = line.find("=")
                if eq > 0:
                    try:
                        d = float(line[eq + 1:])
                        print(label, "%.2f m" % d)
                    except ValueError:
                        pass
    time.sleep_ms(20)