LoraStack is a high level library that uses the MCCI LMiC LoRaWAN implementation combined with a flexible ParameterStore to present a simple API to provision, join, and sendBytes on The Things Network.

Basic Use

#include <LoraStack.h>

#include <ParameterStore.h>
#include <RamStore.h>

#include <Timer.h>

// Lorawan Device ID, App ID, and App Key
const char *devEui = "0001020304050607";
const char *appEui = "0001020304050607";
const char *appKey = "000102030405060708090A0B0C0D0E0F";

#define MY_FREQUENCY_PLAN  // One of TTN_FP_EU868, TTN_FP_US915, TTN_FP_AS920_923, TTN_FP_AS923_925, TTN_FP_KR920_923

// Using RamStore for quick start. In a real device you
// would have EEPROM or FRAM or some other non-volatile
// store supported by ParameterStore. Or serialize RamStore
// to a file on an SD card.
const int STORE_SIZE = 2000;
RamStore<STORE_SIZE> byteStore;
ParameterStore gParameters(byteStore);

// Create lower level hardware interface with access to parameters
const Arduino_LoRaWAN::lmic_pinmap define_lmic_pins = {
  // Feather LoRa wiring with IO1 wired to D6
  .nss = 8, // Chip select
  .rxtx = LMIC_UNUSED_PIN,
  .rst = 4,
  .dio = {3, 6, LMIC_UNUSED_PIN},
};
LoraStack_LoRaWAN lorawan(define_lmic_pins, gParameters);
// Create high level interface to TTN
LoraStack ttn(lorawan, gParameters, MY_FREQUENCY_PLAN);

Timer gTimer;

void setup() {
  bool status = ttn.join(appEui, devEui, appKey);
  if (!status) {
      Log.Error(F("Failed to provision device!" CR));
      while (1);
  }

  // Setup timer to kick off send every 10 seconds
  gTimer.every(10 * 1000, [](){
    // Prepare payload of 1 byte to indicate LED status
    byte payload[1];
    payload[0] = (digitalRead(LED_BUILTIN) == HIGH) ? 1 : 0;

    // Send it off
    ttn.sendBytes(payload, sizeof(payload));
  });
}

void loop() {
  ttn.loop(); // Call often to do LoRaWAN work

  gTimer.update();

  delay(10); // Not too long!
}

API

The LoraStack interface is modeled after the TheThingsNetwork interface defined in TheThingsNetwork.h.

A critical difference is that the The Things Network library relies on the Microchip RN2xx3 module. This chip dramatically reduces the amount of code required to initialize the LoRaWAN system, because all your code does is communicate with the module over a serial line. The module provides storage for network layer parameters like Frame count. Also, the module performs LoRaWAN tasks in parallel with your microprocessor which means that a sketch can call delay(10000) after a sendBytes with impunity - LoRaWAN transmission and reception will continue on the other chip.

In contrast, LoraStack is based on LMiC which runs the LoRaWAN code on the same processor. Therefore, long delay calls are not allowed because ttn.loop() must be called often! In addition, LoraStack requires specifying what your device offers as a storage medium and what pins are used for sending chip select and reset and receiving interrupts from the Semtech radio.

Note: Frankly, delay() calls are a waste of either time or power and you should learn to structure your code such that they are unnecessary. For periodic actions you can use something like the Timer library used above. To manage more complex state and periodic actions, and still breathe easy, consider using the Respire library.

Tests

When you submit pull requests, please include tests.

Copyright (c) 2018 Frank Leon Rose