Using the “Wio-SX1262 for XIAO” to easily build LoRa point-to-point communication with various XIAOs

Products & Technology LoRa
21

Hi there,

So I got the Open Receiver code up on the Dev Expansion Board, Displays “Beacon Message” on first line and is sent in // REV 5.5b - SX1262 Beacon Sender with LED + Button + Power Modes // Posted below.
Press the button to send message with different power levels…
on the Sender (beacon) intervals of 2 dB Transmit power. Watch display on Open receiver and note the RSSI & SNR .
(next experiment will be a press button on each end to change modes.)
OPEN Receiver:

WIN_20250401_11_35_05_Pro
WIN_20250401_11_35_05_Pro1280×720 135 KB

// REV 5.6n - SX1262 Open Receiver with OLED Display
// Board: ESP32-S3 with SX1262 LoRa Module + OLED (XIAO Expansion Board)
// Receives LoRa messages and displays: 
//   1) Beacon Message (1st line)
//   2) RSSI and SNR values (formatted & centered)
//   3) Blinks onboard LED (GPIO 48) on message reception
//   4) Serial output stays consistent with previous 5.5b version

#include <RadioLib.h>
#include <Wire.h>
#include <U8g2lib.h>

// SX1262 Module Pins: NSS, DIO1, RST, BUSY
SX1262 radio = new Module(41, 39, 42, 40);

// OLED: I2C (128x64), flipped orientation (USB on right side)
U8G2_SSD1306_128X64_NONAME_F_HW_I2C display(U8G2_R0, U8X8_PIN_NONE);

// LED for RX activity
const int LED_PIN = 48;

// Last received values for change detection
float lastRSSI = 0;
float lastSNR = 0;
String lastMsg = "";

// Thresholds for display update
const float RSSI_THRESHOLD = 0.25;
const float SNR_THRESHOLD = 0.25;

void setup() {
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);

  Serial.begin(115200);
  delay(500);
  Serial.println();
  Serial.println(F("// REV 5.6n - SX1262 Open Receiver with OLED Display"));
  Serial.println(F("// Board: ESP32-S3 with SX1262 LoRa Module + OLED"));
  Serial.print(F("Initializing SX1262 LoRa radio... "));

  if (radio.begin() != RADIOLIB_ERR_NONE) {
    Serial.println(F("FAILED!"));
    while (true);
  }
  Serial.println(F("SUCCESS!"));
  Serial.println(F("Listening for LoRa messages..."));

  // LoRa radio config
  radio.setOutputPower(22);
  radio.setSpreadingFactor(7);
  radio.setBandwidth(125.0);
  radio.setCodingRate(5);

  // OLED startup screen
  display.begin();
  display.setFlipMode(1);  // Flip vertically for correct orientation
  display.clearBuffer();
  display.setFont(u8g2_font_6x12_tf);
  display.setCursor(0, 12);
  display.print("SX1262 Open Receiver");
  display.setCursor(0, 28);
  display.print("XIAO S3 + OLED");
  display.setCursor(0, 44);
  display.print("REV 5.6n");
  display.sendBuffer();
  delay(2000);

  // Initial Listening Screen
  display.clearBuffer();
  display.setCursor(0, 12);
  display.print("Listening...");
  display.sendBuffer();
}

void loop() {
  String msg;
  int state = radio.receive(msg);

  if (state == RADIOLIB_ERR_NONE) {
    float rssi = radio.getRSSI();
    float snr = radio.getSNR();
    bool updated = false;

    if (msg != lastMsg) {
      Serial.print("Received: ");
      Serial.println(msg);
      lastMsg = msg;
      updated = true;
    }

    if (abs(rssi - lastRSSI) > RSSI_THRESHOLD || abs(snr - lastSNR) > SNR_THRESHOLD) {
      Serial.print("  RSSI: ");
      Serial.print(rssi, 2);
      Serial.print(" dBm\tSNR: ");
      Serial.print(snr, 2);
      Serial.println(" dB");
      lastRSSI = rssi;
      lastSNR = snr;
      updated = true;
    } else {
      Serial.print(".");
    }

    if (updated) {
      display.clearBuffer();
      display.setFont(u8g2_font_6x12_tf);
      display.setCursor(0, 12);
      display.print(lastMsg);  // Line 1

      display.setCursor(0, 28);
      display.print("  RSSI    -    SNR");  // Line 3

      display.setFont(u8g2_font_7x13B_tf);
      display.setCursor(10, 44);
      display.printf("%.0f", lastRSSI);
      display.setCursor(74, 44);
      display.printf("%.2f", lastSNR);

      display.setFont(u8g2_font_6x12_tf);
      display.setCursor(15, 60);
      display.print("dBm");
      display.setCursor(86, 60);
      display.print("dB");

      display.sendBuffer();
    }

    digitalWrite(LED_PIN, HIGH);
    delay(30);
    digitalWrite(LED_PIN, LOW);
  }
}

Serial output for receiver ;


// REV 5.6n - SX1262 Open Receiver with OLED Display
// Board: ESP32-S3 with SX1262 LoRa Module + OLED
Initializing SX1262 LoRa radio... SUCCESS!
Listening for LoRa messages...
Received: Seeed Studio
  RSSI: -125.00 dBm	SNR: -9.25 dB

// REV 5.6n - SX1262 Open Receiver with OLED Display
// Board: ESP32-S3 with SX1262 LoRa Module + OLED
Initializing SX1262 LoRa radio... SUCCESS!
Listening for LoRa messages...
Received: Seeed Studio
  RSSI: -125.00 dBm	SNR: -8.75 dB
.  RSSI: -125.00 dBm	SNR: -9.25 dB
  RSSI: -125.00 dBm	SNR: -8.75 dB
.  RSSI: -125.00 dBm	SNR: -9.25 dB
...  RSSI: -125.00 dBm	SNR: -8.50 dB
  RSSI: -125.00 dBm	SNR: -9.25 dB
  RSSI: -126.00 dBm	SNR: -9.50 dB
.  RSSI: -125.00 dBm	SNR: -9.25 dB
..  RSSI: -126.00 dBm	SNR: -9.50 dB
  RSSI: -125.00 dBm	SNR: -9.25 dB
  RSSI: -126.00 dBm	SNR: -9.50 dB
  RSSI: -126.00 dBm	SNR: -10.50 dB
  RSSI: -125.00 dBm	SNR: -8.75 dB
  RSSI: -126.00 dBm	SNR: -9.75 dB
.  RSSI: -125.00 dBm	SNR: -8.50 dB
  RSSI: -125.00 dBm	SNR: -9.00 dB
.
  RSSI: -115.00 dBm	SNR: 1.25 dB
  RSSI: -115.00 dBm	SNR: 1.75 dB
  RSSI: -115.00 dBm	SNR: 1.25 dB
  RSSI: -113.00 dBm	SNR: 3.50 dB
  RSSI: -117.00 dBm	SNR: -0.50 dB
  RSSI: -114.00 dBm	SNR: 2.00 dB
.....  RSSI: -114.00 dBm	SNR: 2.50 dB
  RSSI: -114.00 dBm	SNR: 2.00 dB
..  RSSI: -115.00 dBm	SNR: 1.25 dB
  RSSI: -114.00 dBm	SNR: 1.75 dB
  RSSI: -116.00 dBm	SNR: 0.25 dB
  RSSI: -114.00 dBm	SNR: 2.25 dB
.....  RSSI: -114.00 dBm	SNR: 1.75 dB
  RSSI: -115.00 dBm	SNR: 1.25 dB
  RSSI: -114.00 dBm	SNR: 2.00 dB
.....  RSSI: -113.00 dBm	SNR: 2.50 dB
  RSSI: -114.00 dBm	SNR: 2.00 dB
..  RSSI: -114.00 dBm	SNR: 2.50 dB
..  RSSI: -113.00 dBm	SNR: 2.75 dB
  RSSI: -114.00 dBm	SNR: 2.50 dB
.  RSSI: -114.00 dBm	SNR: 2.00 dB
  RSSI: -114.00 dBm	SNR: 2.50 dB
....  RSSI: -115.00 dBm	SNR: 1.00 dB
  RSSI: -113.00 dBm	SNR: 3.00 dB
  RSSI: -110.00 dBm	SNR: 5.75 dB
  RSSI: -108.00 dBm	SNR: 7.00 dB
...............................  RSSI: -109.00 dBm	SNR: 6.25 dB
  RSSI: -108.00 dBm	SNR: 7.25 dB
  RSSI: -109.00 dBm	SNR: 6.50 dB
.  RSSI: -108.00 dBm	SNR: 6.75 dB
.  RSSI: -109.00 dBm	SNR: 6.25 dB
  RSSI: -108.00 dBm	SNR: 7.25 dB
................  RSSI: -107.00 dBm	SNR: 7.25 dB
  RSSI: -109.00 dBm	SNR: 6.25 dB
  RSSI: -108.00 dBm	SNR: 7.25 dB
..  RSSI: -108.00 dBm	SNR: 6.75 dB
.  RSSI: -109.00 dBm	SNR: 7.00 dB
..  RSSI: -108.00 dBm	SNR: 6.50 dB
.  RSSI: -108.00 dBm	SNR: 7.00 dB
.................

Beacon Sender…:

WIN_20250401_12_29_49_Pro (4)
WIN_20250401_12_29_49_Pro (4)1280×720 79 KB

WIN_20250401_12_29_43_Pro
WIN_20250401_12_29_43_Pro1280×720 78.8 KB

// REV 5.5b - SX1262 Beacon Sender with LED + Button + Power Modes
// Board: ESP32-S3 with SX1262 LoRa Module
// Sends "Seeed Studio" as beacon every 5 seconds
// LED on GPIO 48 blinks on TX
// Button on GPIO 21 cycles TX power level (2 to 22 dBm)

#include <RadioLib.h>

#define NSS     41
#define DIO1    39
#define RST     42
#define BUSY    40
#define LED_PIN 48
#define BTN_PIN 21

SX1262 radio = new Module(NSS, DIO1, RST, BUSY);

const char beaconMessage[] = "Seeed Studio";
int txPower = 22;
unsigned long lastSendTime = 0;
const unsigned long beaconInterval = 5000;

int lastButtonState = HIGH;
bool firstPrint = true;

void setup() {
  pinMode(LED_PIN, OUTPUT);
  pinMode(BTN_PIN, INPUT_PULLUP);
  digitalWrite(LED_PIN, LOW);

  Serial.begin(115200);
  delay(1000);
  Serial.println();
  Serial.println("// REV 5.5b - SX1262 Beacon Sender");
  Serial.println("// Board: ESP32-S3 with SX1262 LoRa Module");
  Serial.print("Initializing SX1262 LoRa radio... ");

  if (radio.begin() != RADIOLIB_ERR_NONE) {
    Serial.println("FAILED!");
    while (true);
  }

  Serial.println("SUCCESS!");
  radio.setOutputPower(txPower);
  radio.setSpreadingFactor(7);
  radio.setBandwidth(125.0);
  radio.setCodingRate(5);

  Serial.print("TX Power: ");
  Serial.print(txPower);
  Serial.println(" dBm");
  Serial.println("Beacon message: \"Seeed Studio\"");
  Serial.println("Transmitting every 5 seconds...\n");
}

void loop() {
  unsigned long now = millis();

  // Button handling to change TX power
  int btnState = digitalRead(BTN_PIN);
  if (btnState == LOW && lastButtonState == HIGH) {
    txPower += 2;
    if (txPower > 22) txPower = 2;
    radio.setOutputPower(txPower);
    Serial.print("\nTX Power changed to: ");
    Serial.print(txPower);
    Serial.println(" dBm");
    delay(250);  // debounce
  }
  lastButtonState = btnState;

  // Send beacon every interval
  if (now - lastSendTime >= beaconInterval) {
    lastSendTime = now;

    digitalWrite(LED_PIN, HIGH);
    int state = radio.transmit(beaconMessage);
    digitalWrite(LED_PIN, LOW);

    if (state == RADIOLIB_ERR_NONE) {
      if (firstPrint) {
        Serial.print("Sent: ");
        Serial.println(beaconMessage);
        firstPrint = false;
      } else {
        Serial.print(".");
      }

      static int dotCount = 0;
      dotCount++;
      if (dotCount % 80 == 0) Serial.println();
    } else {
      Serial.print("Transmit failed, code ");
      Serial.println(state);
    }
  }
}

Sender Serial Output.:

// REV 5.5b - SX1262 Beacon Sender
// Board: ESP32-S3 with SX1262 LoRa Module
Initializing SX1262 LoRa radio... SUCCESS!
TX Power: 22 dBm
Beacon message: "Seeed Studio"
Transmitting every 5 seconds...

Sent: Seeed Studio
...............................................................................
................................................................................
................................................................................
.......................................................................
TX Power changed to: 2 dBm
.........
.
TX Power changed to: 4 dBm
.....
TX Power changed to: 6 dBm
...
TX Power changed to: 8 dBm
..........
TX Power changed to: 10 dBm
....
TX Power changed to: 12 dBm
.............................................
TX Power changed to: 14 dBm

TX Power changed to: 16 dBm
.
TX Power changed to: 18 dBm

TX Power changed to: 20 dBm

TX Power changed to: 22 dBm
...
TX Power changed to: 2 dBm
........
................................................................................
........................................................
// REV 5.5b - SX1262 Beacon Sender
// Board: ESP32-S3 with SX1262 LoRa Module
Initializing SX1262 LoRa radio... SUCCESS!
TX Power: 22 dBm
Beacon message: "Seeed Studio"
Transmitting every 5 seconds...

Sent: Seeed Studio
...............................................................................
...................................

Starts at 22 dBm , press button goes to 2,4,6,8, etc…

HTH
GL :slight_smile: PJ :v:
Like, Share and subscribe… LOL