LoRa_TRX.ino

// Adapted for TTGO T3 1.6.1 LoRa32 board

#include "BluetoothSerial.h"
#include <stdio.h>

// used to get BT MAC
#include "esp_bt_main.h"
#include "esp_bt_device.h"

#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
#endif

//Libraries for LoRa
#include <SPI.h>
#include <LoRa.h>  // by Sandeep Mistry

//Libraries for OLED Display
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

/*Frequency setup*/
#define BAND 869525000  //868 MHz band
//#define BAND 433875000   //433 MHz band

//Board: TTGO T3 1.6.1 LoRa32 board
//LoRa and OLED Pins
#define SCK 5
#define MISO 19
#define MOSI 27
#define SS 18
#define RST 23
#define DIO0 26
#define DIO1 0  // GPIO 33 NON EXISTENT ON TTGO T3 1.6.1
#define DIO2 0  // GPIO 32 NON EXISTENT ON TTGO T3 1.6.1

//OLED pins
#define OLED_SDA 21
#define OLED_SCL 22
#define OLED_RST 0        // NON EXISTENT ON TTGO T3 1.6.1
#define SCREEN_WIDTH 128  // OLED display width, in pixels
#define SCREEN_HEIGHT 64  // OLED display height, in pixels

#define LED_BUILTIN 25

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RST);

BluetoothSerial SerialBT;
String LoRaData;
String message;

char str[7];

void setup() {
  pinMode(LED_BUILTIN, OUTPUT); // green led

  Serial.begin(115200);
  initBluetooth();
  const uint8_t* point = esp_bt_dev_get_address();  //get BT MAC address last 3 hex digits
  sprintf(str, "%02X%02X%02X", (int)point[3], (int)point[4], (int)point[5]);
  SerialBT.begin(str);  //Bluetooth device name
  Serial.println("Started, pair it with bluetooth!");

  //initialize OLED
  Wire.begin(OLED_SDA, OLED_SCL);
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3c, false, false)) {  // Address 0x3C for 128x32
    Serial.println(F("SSD1306 allocation failed"));
    for (;;)
      ;  // Don't proceed, loop forever
  }

  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.print("LoRa_TRX by DM5LG");
  display.display();

  Serial.println("LoRa Receiver Test");

  //SPI LoRa pins
  SPI.begin(SCK, MISO, MOSI, SS);
  //setup LoRa transceiver module
  LoRa.setPins(SS, RST, DIO0);

  if (!LoRa.begin(BAND)) {
    Serial.println("Starting LoRa failed!");
    while (1)
      ;
  }

  Serial.println("LoRa Initializing OK!");
  display.setCursor(0, 10);
  display.setTextSize(1);
  display.println("Version 0.2 Beta");
  display.display();

  //LoRa settings, same as meshtastic defaults long-fast, SF11 BW250 CR8
  LoRa.setSpreadingFactor(11);
  LoRa.setSignalBandwidth(250000);
  LoRa.setCodingRate4(8);

  // Change sync word to match the sender
  // The sync word assures you don't get LoRa messages from other LoRa transceivers
  // ranges from 0x00 - 0xFF, 0x12 is private network (default)
  LoRa.setSyncWord(0x12);

  LoRa.enableCrc();
  LoRa.setTxPower(12);  // dBm
  delay(5000);

  display.clearDisplay();
  display.setCursor(0, 10);
  display.setTextSize(1);
  display.print("LORA RX ");
  display.println(str);
  display.display();

  // LoRa send start BT digit, kind of a start ping
  LoRa.beginPacket();
  LoRa.println(str);
  LoRa.endPacket();
}

void loop() {


  // usbserial input also
  while (Serial.available()) {
    // read the incoming byte:
    char incomingThing = Serial.read();
    message += String(incomingThing);

    // sending a packet
    if (incomingThing == '\n') {

      display.clearDisplay();
      display.setCursor(0, 0);
      display.println("LORA TX");
      display.display();

      LoRa.beginPacket();
      LoRa.print(message);
      LoRa.endPacket();

      display.clearDisplay();
      display.setCursor(0, 10);
      display.print("LORA RX ");
      display.println(str);
      display.display();

      Serial.println(message);
    }
  }

  // BT input too
  while (SerialBT.available()) {

    //Serial.write(SerialBT.read());
    char incomingChar = SerialBT.read();
    message += String(incomingChar);

    // sending a packet
    if (incomingChar == '\n') {

      display.clearDisplay();
      display.setCursor(0, 0);
      display.println("LORA TX");
      display.display();

      LoRa.beginPacket();
      LoRa.print(message);
      LoRa.endPacket();

      display.clearDisplay();
      display.setCursor(0, 10);
      display.print("LORA RX ");
      display.println(str);
      display.display();
    }
  }

  //try to parse packet
  int packetSize = LoRa.parsePacket();
  if (packetSize) {
    //received a packet
    Serial.print("Received packet: ");

    //read packet
    while (LoRa.available()) {
      LoRaData = LoRa.readString();
      Serial.print(LoRaData);
    }

    //print RSSI and SNR  of packet
    int rssi = LoRa.packetRssi();
    float snr = LoRa.packetSnr();
    Serial.print(" with RSSI ");
    Serial.println(rssi);
    Serial.print(" with SNR ");
    Serial.println(snr);

    //send LoRaData and RSSI and SNR via SerialBT
    SerialBT.println(LoRaData + "RSSI:" + rssi + " dBm " + "SNR:" + snr + " dB");

    // Display information
    display.clearDisplay();
    display.setCursor(0, 0);
    display.print("Received packet:");
    display.setCursor(0, 10);
    display.print("RSSI:");
    display.setCursor(30, 10);
    display.print(rssi);
    display.setCursor(0, 20);
    display.print("SNR:");
    display.setCursor(30, 20);
    display.print(snr);
    display.setCursor(0, 30);
    display.print(LoRaData);
    display.display();

    digitalWrite(LED_BUILTIN, HIGH); // turn the LED on to signal a received sentence
    delay(100);             // wait for 100 milliseconds
    digitalWrite(LED_BUILTIN, LOW);  // turn the LED off
    }
  message = "";
}

// this seems necessary to retrieve the BT MAC address, might be done better in some other way
bool initBluetooth() {

  if (!btStart()) {
    Serial.println("Failed to initialize controller");
    return false;
  }

  if (esp_bluedroid_init() != ESP_OK) {
    Serial.println("Failed to initialize bluedroid");
    return false;
  }

  if (esp_bluedroid_enable() != ESP_OK) {
    Serial.println("Failed to enable bluedroid");
    return false;
  }
}