Arduino Mega 2560 Integration

In this guide

we explain how to connect a GrowSpace developer tag to an Arduino Mega 2560 via serial communication and receive real-time location data using the lec and lep commands. We also provide example code to show how to build a stable high-speed communication setup using the Mega 2560’s hardware serial ports.

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Required Materials

• Arduino Mega 2560 Board

• GrowSpace Developer Tag

• Arduino IDE Program (Official: https://www.arduino.cc/en/software)

• Jumper wires

Jumper cables

Included serial (connection cable)

⚠️ The UNO board has only one hardware serial port, which may cause errors during high-speed communication. The Mega 2560 provides Serial1 to Serial3, enabling more stable and reliable communication.

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Arduino IDE Setup and Board Connection

• Open the Arduino IDE after installation.

• In the top menu, apply the following settings:

  • Tools > Board > Arduino Mega or Mega 2560

  

  • Tools > Port > Select the connected COM port (e.g. COM3)

  

• Connect the Arduino Mega 2560 to your PC via USB.

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Hardware Pin Connection

Connect the pins using the right-side connector (5V only) on the GrowSpace developer tag as shown below:

Developer Tag Pin	Arduino Mega pin
TX	RX1 (pin 19)
RX	TX1 (pin 18)
5V	5V
GND	GND

🔄 TX and RX must be cross-connected for communication to work properly.

Below is an example of the pin layout on the Arduino Mega board.

Connect the GrowSpace developer tag using TX1 (pin 18) and RX1 (pin 19) of Serial1.

Connection example: Developer tag connected to Arduino Mega 2560

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Serial Relay Example (Basic Communication Test)

String inputFromSerial0 = "";
String inputFromSerial1 = "";

void setup() {
  Serial.begin(115200);    // USB Serial (Serial0)
  Serial1.begin(115200);   // Hardware Serial1 ( pin 18 TX1, pin 19 RX1)
}

void loop() {
  // serialEvent() and serialEvent1() are called automatically
}

// Input from Serial0 → sent to Serial1 (with carriage return \r added)
void serialEvent() {
  while (Serial.available()) {
    char inChar = (char)Serial.read();
    if (inChar != '\n') {
      inputFromSerial0 += inChar;
    }

    if (inChar == '\n') {
      Serial1.print(inputFromSerial0);
      Serial1.print('\r');
      inputFromSerial0 = "";
    }
  }
}

// Input from Serial1 → sent to Serial0
void serialEvent1() {
  while (Serial1.available()) {
    char inChar = (char)Serial1.read();
    inputFromSerial1 += inChar;

    if (inChar == '\n') {
      Serial.print("From Serial1: ");
      Serial.print(inputFromSerial1);
      inputFromSerial1 = "";
    }
  }
}

Explanation

• In setup(), both the USB serial (Serial) and the hardware serial (Serial1) are initialized.

• serialEvent() sends the string entered from the PC (Serial0) to the tag.

• serialEvent1() reads the response from the tag and prints it to the PC.

• When a command is sent, the input is split by newline (\n), and a carriage return (\r) is automatically added.

Serial Monitor Setup Tips

• Baudrate: 115200bps

• Set line ending to: New Line

• If the tag returns system information after sending the si command, the communication is working.

If you type si in the Serial Monitor and receive a valid response, the connection is successful.

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Location Parsing Example Using Commands

String bufferSerial0 = "";
String bufferSerial1 = "";

void setup() {
  Serial.begin(115200);    // USB Serial
  Serial1.begin(115200);   // Serial1 for developer tag connection
}

void loop() {
  // Leave empty, serialEvent / serialEvent1 run automatically
}

// Receive command input from Serial0
void serialEvent() {
  while (Serial.available()) {
    char inChar = (char)Serial.read();
    if (inChar != '\n') {
      bufferSerial0 += inChar;
    }

    if (inChar == '\n') {
      bufferSerial0.trim();  // Remove newline

      if (bufferSerial0.equalsIgnoreCase("lec") || bufferSerial0.equalsIgnoreCase("lep")) {
        Serial.print("Command sent: ");
        Serial.println(bufferSerial0);
        Serial1.print(bufferSerial0); // Append CR only
        Serial1.print('\r');
      } else {
        Serial.println("⚠ Unsupported command.");
      }

      bufferSerial0 = "";
    }
  }
}

// Receive response from Serial1 → parse lec/lep
void serialEvent1() {
  while (Serial1.available()) {
    char inChar = (char)Serial1.read();
    bufferSerial1 += inChar;

    if (inChar == '\n') {
      bufferSerial1.trim();

      if (bufferSerial1.startsWith("POS,")) {
        parseLEP(bufferSerial1);
      } else if (bufferSerial1.startsWith("DIST,")) {
        parseLEC(bufferSerial1);
      } else {
        Serial.println("[Response] " + bufferSerial1);
      }

      bufferSerial1 = "";
    }
  }
}

// --- Parse position only (lep) ---
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();
}

// --- Parse full lec data ---
void parseLEC(String line) {
  Serial.println("[LEC Distance + Position Result]");
  int posIndex = line.indexOf("POS,");
  if (posIndex == -1) {
    Serial.println("→ Missing position data");
    return;
  }

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

  Serial.println("▶ Anchor Distance Info:");
  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 Info:");
  parseLEP(posPart);
}

• LEP Command Execution

• LEC Command Execution

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Conclusion

This guide walks you through setting up serial communication between the Arduino Mega 2560 and the GrowSpace developer tag, and receiving real-time location data using the lec and lep commands.

• lep: View X, Y, Z coordinates and quality factor (QF)

• lec: Check anchor information, distance, and full location data