This guide describes how to connect a GrowSpace UWB Developer Tag to an Arduino ESP32 board, send lec and lep commands, and receive and parse real-time location data.

Unlike the UNO, the ESP32 supports multiple hardware serial ports and is highly scalable with a compact footprint—making it ideal for lightweight test environments.

Required Components

To begin serial communication, you’ll need the following:

• Arduino ESP32 board (e.g., DevKitC)

• GrowSpace Developer Tag

• Arduino IDE
• Jumper wires (TX, RX, GND, 3.3V)

Installing Arduino IDE & ESP32 Board Support

1. Install Arduino IDE
   Download the appropriate installer for your OS from the official Arduino website.
   ※ This guide assumes Windows (MSI Installer)
2. Add ESP32 Board to Arduino IDE

• Launch Arduino IDE → Go to File > Preferences

• In Additional Board Manager URLs, add:

https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json

• Navigate to Tools > Board > Board Manager, search for ESP32, and install the package from Espressif Systems

• Set your board to ESP32 Dev Module via Tools > Board
• Select the correct port from Tools > Port

Wiring Configuration

GrowSpace Developer Tags have connectors on both sides.
In this tutorial, we’ll use the left-side connector, which operates at 3.3V.

Developer Tag Pin	ESP32 Pin
TX	GPIO 16 (RX2)
RX	GPIO 17 (TX2)
3.3V	3.3V
GND	GND

주의: TX ↔ RX must be cross-connected
Tag TX → ESP32 RX / Tag RX → ESP32 TX

Refer to your ESP32 DevKit pinout to confirm TX2 and RX2 positions.

Serial Relay Example Code

Upload the following code to verify communication between USB (PC) and Developer Tag (Serial2):

#define SERIAL2_RX 16  // GPIO16
#define SERIAL2_TX 17  // GPIO17

String inputFromSerial = "";
String inputFromSerial2 = "";

void setup() {
  Serial.begin(115200);  // USB Serial
  Serial2.begin(115200, SERIAL_8N1, SERIAL2_RX, SERIAL2_TX);  // Tag connection
  Serial.println("ESP32 Serial <-> Serial2 relay started");
}

void loop() {
  while (Serial.available()) {
    char ch = (char)Serial.read();
    if (ch != '\n') inputFromSerial += ch;

    if (ch == '\n') {
      Serial2.print(inputFromSerial);
      Serial2.print('\r');
      inputFromSerial = "";
    }
  }

  while (Serial2.available()) {
    char ch = (char)Serial2.read();
    inputFromSerial2 += ch;

    if (ch == '\n') {
      Serial.print("[Serial2 Response] ");
      Serial.print(inputFromSerial2);
      inputFromSerial2 = "";
    }
  }
}

Serial Monitor Settings

• Baud rate: 115200
• Newline option: Enabled

Try sending the command si to receive system info from the tag.
If the response appears, the setup is successful.

Parsing Location Data (lec / lep)

We now go beyond simple echo checks and parse real location data:

lep: Outputs position only

lec: Outputs anchor distances + position

LEP Parsing – Tag Position (X, Y, Z)

void parseLEP(String line) {
  Serial.println("[LEP Position Result]");
  int idx = 0;
  String parts[5];
  while (line.length() > 0 && idx < 5) {
    int comma = line.indexOf(',');
    if (comma == -1) {
      parts[idx++] = line;
      break;
    } else {
      parts[idx++] = line.substring(0, comma);
      line = line.substring(comma + 1);
    }
  }

  Serial.print("X: "); Serial.println(parts[1]);
  Serial.print("Y: "); Serial.println(parts[2]);
  Serial.print("Z: "); Serial.println(parts[3]);
  Serial.print("Quality (QF): "); Serial.println(parts[4]);
  Serial.println();
}

• Example Output

LEC Parsing – Anchor Distances + Tag Position

void parseLEC(String line) {
  Serial.println("[LEC Distance + Position Result]");

  int posIndex = line.indexOf("POS,");
  if (posIndex == -1) {
    Serial.println("→ POS data missing");
    return;
  }

  String distPart = line.substring(0, posIndex - 1);
  String posPart = line.substring(posIndex);

  int anchorIdx = 0;
  int anStart = 0;
  while ((anStart = distPart.indexOf("AN", anStart)) != -1) {
    int idStart = anStart + 2;
    int idEnd = distPart.indexOf(",", idStart);
    String id = distPart.substring(idStart, idEnd);

    int valStart = idEnd + 1;
    float x = distPart.substring(valStart, distPart.indexOf(",", valStart)).toFloat();
    valStart = distPart.indexOf(",", valStart) + 1;
    float y = distPart.substring(valStart, distPart.indexOf(",", valStart)).toFloat();
    valStart = distPart.indexOf(",", valStart) + 1;
    float z = distPart.substring(valStart, distPart.indexOf(",", valStart)).toFloat();
    valStart = distPart.indexOf(",", valStart) + 1;
    float d = distPart.substring(valStart, distPart.indexOf(",", valStart)).toFloat();

    Serial.print("AN"); Serial.print(anchorIdx++); Serial.print(" (ID "); Serial.print(id); Serial.print("): ");
    Serial.print("x="); Serial.print(x); Serial.print(", y="); Serial.print(y); Serial.print(", z="); Serial.print(z);
    Serial.print(" → Distance: "); Serial.print(d); Serial.println("m");

    anStart = valStart;
  }

  Serial.println("▶ Tag Position:");
  parseLEP(posPart);
}

• Example Output

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Conclusion

With this guide, you’ve learned how to:

• Connect the GrowSpace UWB Developer Tag to an ESP32 board
• Send lec / lep commands
• Parse and display real-time 3D location data via Arduino

Thanks to the ESP32’s flexibility and hardware serial ports, you can quickly build a testbed and verify UWB-based indoor positioning.