Arduino Uno Integration

In this guide

we explain how to connect a GrowSpace UWB listener or developer tag to an Arduino Uno and receive real-time location data using the lep command. Since the Uno has only one hardware serial port, we use AltSoftSerial, a software serial method, to handle data reliably

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Required Materials

• GrowSpace Listener or Developer Tag (GR-LST-1001 or GR-TGD-1001S)

• Arduino Uno board

• Jumper wires

• USB cable (for PC connection)

• Arduino IDE

• AltSoftSerial library (for software serial communication)

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Installing Arduino IDE and Libraries

Install Arduino IDE

• Download and install the version that matches your operating system from the official Arduino website.

Install AltSoftSerial

• Open the Arduino IDE

• Go to the top menu: Sketch > Include Library > Manage Libraries

• Search for AltSoftSerial and install the latest version

Why Use AltSoftSerial?

The Arduino Uno has only one hardware serial port, which is used for the USB connection to your PC. However, the GrowSpace UWB device requires high-speed serial communication at 115200 bps, making it difficult to handle both PC and device communication through the same port.

Limitations of SoftwareSerial

• Unstable at high speeds like 115200 bps

• Can interfere with timers, affecting functions like millis() and delay()

Advantages of AltSoftSerial

• Uses internal timers for more accurate and stable communication

• Works reliably even at high speeds (115200 bps and above)

• Similar to Serial, so it’s easy to use

• On the Uno, RX is fixed to D8 and TX to D9, reducing pin conflicts

Therefore, using AltSoftSerial is recommended to ensure stable communication between the GrowSpace device and the Arduino Uno.

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Serial Pin Connection (AltSoftSerial)

Connect the GrowSpace device to the Arduino Uno as shown below. Since the Uno supports 5V devices, use the right-side connector (5V-based) on the GrowSpace tag.

GrowSpace Device Pins	Arduino Uno Pin
HV (5V)	5V
GND	GND
TXD	D8
RXD	D9

⚠️ TX and RX must be cross-connected: Device TX → Uno D8 (AltSoftSerial RX), Device RX → Uno D9 (AltSoftSerial TX)

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AltSoftSerial-Based Data Receiving Example Code

#include <AltSoftSerial.h>

AltSoftSerial altSerial;  // RX: D8, TX: D9

void setup() {
  Serial.begin(115200);     // USB Serial
  altSerial.begin(115200);  // GrowSpace Device Serial
  delay(100);

  // Device Reset
  altSerial.print("reset\r");
  delay(1000);

  // Clear Buffer
  while (altSerial.available()) {
    altSerial.read();
  }

  // Start Location Request
  altSerial.print("lep\r");
}

void loop() {
  while (altSerial.available()) {
    char c = altSerial.read();
    Serial.write(c);  // Print to PC
  }
}

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Serial Monitor Setup and Test

• After uploading the code, connect the Arduino Uno to your PC.

• In the Arduino IDE, go to Tools > Serial Monitor.

• Set the baud rate to 115200 and enable newline.

Example Output (Applicable to Both Developer Tag and Listener)

POS,0,0104,12.34,56.78,9.01,95,BC

or

X: 12.34, Y: 56.78, Z: 9.01

If the GrowSpace device is working properly, you will see output like this with location data.

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Troubleshooting Guide

• If no output appears:

  • Check the jumper wire connections.

  • Make sure the AltSoftSerial library is properly installed.

  • Re-select the correct port for the Uno board, reboot the board, and try again.

• For more stable communication:

  • We recommend using the Arduino Mega 2560, which supports four hardware serial ports.

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Conclusion

In this manual, we showed how to connect a GrowSpace UWB listener or developer tag to an Arduino Uno and receive real-time location data. The location data received using the lep command can be applied to various indoor positioning projects and RTLS (Real-Time Location System) applications.