LoRaWan – BitWise

joining TheThingsNetwork

LoRaWan and TheThingsNetwork are quite popular in my country, although they may have lost part of their momentum lately^*. With no particular use case in mind, it was mainly curiosity that made me purchase a TTGO T-Beam board and join TheThingsNetwork.

The board comes in a box with two antennas (LoRa and GPS) and header pins

My T-Beam (T22 V 1.1) is basically an ESP32 WROVER module with an onboard SX1276 LoRa radio and a u-blox NEO-M8N GPS module, a type 18650 battery holder and an AXP192 power management chip. The manufacturer’s documentation is a bit confusing, being divided over two apparently official github repositories: https://github.com/LilyGO/TTGO-T-Beam and https://github.com/Xinyuan-LilyGO/LilyGO-T-Beam. Also, board versions up to 0.7 are significantly different from later versions.

First, I successfully tested the GPS receiver of my version 1.1 board with this sketch. Its code shows the most important differences between version 1.x boards and previous versions (like 0.7). TX and RX pins for the GPS receiver are now 34 and 12 instead of 12 and 15. Furthermore, the newer boards have a power management chip (AXP192) that lets you control power sink to individual board components. It requires an include of the axp20x library as well as code for explicitly powering used components. I recommend to take a look at the examples from that library.

Testing the T-Beam’s LoRa radio either requires a second LoRa board (which I don’t have), or making ‘The Thing’ talk to TheThingsNetwork. I went for the TTN option, obviously. And with a GPS on board, a GPS tracker was a logical choice for my first LoRaWan sketch.

After creating an account on the TTN website, I had to register an ‘Application’ and a ‘Device’, as well as provide a Payload Format Decode function^**. Along the way, the system generated some identification codes: Application EUI, Device EUI and Application Key, needed for the OTAA Activation Method that I selected.

Then I ran the sketch below, which I compiled from several sources. After a minute or so, the Serial monitor reported a GPS fix, continued with “EV_JOINING”, and … that was it. Apart from a faulty device or a software issue, I also had to consider the possibility that my T-Beam was not within range of a TTN gateway. Hard to debug, but I was lucky.

TheThingsNetwork Console pages show Application Key and EUIs in hex format. Clicking the <> icon in front of a value will show it in C-style format and then the icon next to it lets you toggle between msb and lsb. It turned out that my sketch expected both EUIs to be in lsb format and the Application Key in msb format. I had used msb for all three of them!

After correcting the EUI values in device_config.h, the “EV_JOINING” in the Serial monitor was followed by “EV_JOINED” and “Good night…”, indicating that the device had been seen by a TTN gateway and gone into deep sleep mode. From that moment on, its payload messages, sent every two minutes (as set in my sketch), appeared at the Data tab of my application’s TTN Console. Looks like my T-Beam is a TTN node!

In order to do something useful with your uploaded data, the TTN Console offers several ‘Integrations’. For my GPS tracker I first tried TTN Mapper, making my GPS readings contribute to a coverage map of TTN gateways. It also lets you download your data in csv format. However, I didn’t see my readings on their map so far, perhaps because my signal was picked up by a gateway with unspecified location. So I switched to HTTP Integration in order to have all readings sent to an endpoint on my php/MySQL server.

My next steps will be testing coverage and reception of the T-Beam when used during a car travel, as wel as trying some other integrations. Should that raise my enthusiasm for TheThingsNetwork enough, then I might even consider to run my own TTN gateway in order to improve LoRaWan coverage in my area.

In summary, making my Thing join the Network wasn’t just plug & play, so I hope this post and the below mixture of mainly other people’s code will be of any help to TTN starters.

^* based on (the lack of) recent activity of TTN communities in my area.

Code for a T-Beam v 1.x (with AXP192 power control chip), compiled from several sources. It sends latitude, longitude, altitude, hdop and number of satellites to TTN.

GPS-Mapper.ino

// If you are in USA on a 915Mhz network instead of an european / 868 Mhz one,
//   you MUST modify the arduino lmic library "config.h" to enable CFG_us915 instead of CFG_eu868.
// That "config.h" should be in the same folder as the "lmic.h" file in your arduino folders.
#include <lmic.h>
#include <hal/hal.h>

// UPDATE our "device_config.h" file in the same folder WITH YOUR TTN KEYS AND ADDR.
#include "device_config.h"
#include "gps.h"

#include <WiFi.h>
#include <esp_sleep.h>
#include "axp20x.h"
AXP20X_Class axp;

// T-Beam specific hardware
#undef BUILTIN_LED
#define BUILTIN_LED 21

char s[32]; // used to sprintf for Serial output
uint8_t txBuffer[10];
gps gps;
static osjob_t sendjob;

// Those variables keep their values after software restart or wakeup from sleep, not after power loss or hard reset !
RTC_NOINIT_ATTR int RTCseqnoUp, RTCseqnoDn;
#ifdef USE_OTAA
RTC_NOINIT_ATTR u4_t otaaDevAddr;
RTC_NOINIT_ATTR u1_t otaaNetwKey[16];
RTC_NOINIT_ATTR u1_t otaaApRtKey[16];
#endif

// Schedule TX every this many seconds (might become longer due to duty cycle limitations).
const unsigned TX_INTERVAL = 120;

// Pin mapping for TBeams, might not suit the latest version > 1.0 ?
const lmic_pinmap lmic_pins = {
  .nss = 18,
  .rxtx = LMIC_UNUSED_PIN,
  .rst = LMIC_UNUSED_PIN, // was "14,"
  .dio = {26, 33, 32},
};

// These callbacks are only used in over-the-air activation.
#ifdef USE_OTAA
void os_getDevEui (u1_t* buf) {
  memcpy_P(buf, DEVEUI, 8);
}
void os_getArtEui (u1_t* buf) {
  memcpy_P(buf, APPEUI, 8);
}
void os_getDevKey (u1_t* buf) {
  memcpy_P(buf, APPKEY, 16);
}
#else
void os_getArtEui (u1_t* buf) { }
void os_getDevEui (u1_t* buf) { }
void os_getDevKey (u1_t* buf) { }
#endif

void storeFrameCounters()
{
  RTCseqnoUp = LMIC.seqnoUp;
  RTCseqnoDn = LMIC.seqnoDn;
  sprintf(s, "Counters stored as %d/%d", LMIC.seqnoUp, LMIC.seqnoDn);
  Serial.println(s);
}

void restoreFrameCounters()
{
  LMIC.seqnoUp = RTCseqnoUp;
  LMIC.seqnoDn = RTCseqnoDn;
  sprintf(s, "Restored counters as %d/%d", LMIC.seqnoUp, LMIC.seqnoDn);
  Serial.println(s);
}

void setOrRestorePersistentCounters()
{
  esp_reset_reason_t reason = esp_reset_reason();
  if ((reason != ESP_RST_DEEPSLEEP) && (reason != ESP_RST_SW))
  {
    Serial.println(F("Counters both set to 0"));
    LMIC.seqnoUp = 0;
    LMIC.seqnoDn = 0;
  }
  else
  {
    restoreFrameCounters();
  }
}

void onEvent (ev_t ev) {
  switch (ev) {
    case EV_SCAN_TIMEOUT:
      Serial.println(F("EV_SCAN_TIMEOUT"));
      break;
    case EV_BEACON_FOUND:
      Serial.println(F("EV_BEACON_FOUND"));
      break;
    case EV_BEACON_MISSED:
      Serial.println(F("EV_BEACON_MISSED"));
      break;
    case EV_BEACON_TRACKED:
      Serial.println(F("EV_BEACON_TRACKED"));
      break;
    case EV_JOINING:
      Serial.println(F("EV_JOINING"));
      break;
    case EV_JOINED:
      Serial.println(F("EV_JOINED"));
#ifdef USE_OTAA
      otaaDevAddr = LMIC.devaddr;
      memcpy_P(otaaNetwKey, LMIC.nwkKey, 16);
      memcpy_P(otaaApRtKey, LMIC.artKey, 16);
      sprintf(s, "got devaddr = 0x%X", LMIC.devaddr);
      Serial.println(s);
#endif
      // Disable link check validation (automatically enabled
      // during join, but not supported by TTN at this time).
      LMIC_setLinkCheckMode(0);
      // TTN uses SF9 for its RX2 window.
      LMIC.dn2Dr = DR_SF9;
      break;
    case EV_RFU1:
      Serial.println(F("EV_RFU1"));
      break;
    case EV_JOIN_FAILED:
      Serial.println(F("EV_JOIN_FAILED"));
      break;
    case EV_REJOIN_FAILED:
      Serial.println(F("EV_REJOIN_FAILED"));
      break;
    case EV_TXCOMPLETE:
      Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)"));
      digitalWrite(BUILTIN_LED, LOW);
      if (LMIC.txrxFlags & TXRX_ACK) {
        Serial.println(F("Received Ack"));
      }
      if (LMIC.dataLen) {
        sprintf(s, "Received %i bytes of payload", LMIC.dataLen);
        Serial.println(s);
        sprintf(s, "RSSI %d SNR %.1d", LMIC.rssi, LMIC.snr);
        Serial.println(s);
      }
      storeFrameCounters();
      // Schedule next transmission
      Serial.println("Good night...");
      axp.setChgLEDMode(AXP20X_LED_OFF);
      axp.setPowerOutPut(AXP192_LDO2, AXP202_OFF);
      axp.setPowerOutPut(AXP192_LDO3, AXP202_OFF);
      axp.setPowerOutPut(AXP192_DCDC2, AXP202_OFF);
      axp.setPowerOutPut(AXP192_DCDC1, AXP202_OFF);
      axp.setPowerOutPut(AXP192_EXTEN, AXP202_OFF);
      delay(20);  
      esp_sleep_enable_timer_wakeup(TX_INTERVAL * 1000000);
      esp_deep_sleep_start();
      do_send(&sendjob);
      break;
    case EV_LOST_TSYNC:
      Serial.println(F("EV_LOST_TSYNC"));
      break;
    case EV_RESET:
      Serial.println(F("EV_RESET"));
      break;
    case EV_RXCOMPLETE:
      // data received in ping slot
      Serial.println(F("EV_RXCOMPLETE"));
      break;
    case EV_LINK_DEAD:
      Serial.println(F("EV_LINK_DEAD"));
      break;
    case EV_LINK_ALIVE:
      Serial.println(F("EV_LINK_ALIVE"));
      break;
    default:
      Serial.println(F("Unknown event"));
      break;
  }
}

void do_send(osjob_t* j) {

  // Check if there is not a current TX/RX job running
  if (LMIC.opmode & OP_TXRXPEND)
  {
    Serial.println(F("OP_TXRXPEND, not sending"));
  }
  else
  {
    if (gps.checkGpsFix())
    {
      // Prepare upstream data transmission at the next possible time.
      gps.buildPacket(txBuffer);
      LMIC_setTxData2(1, txBuffer, sizeof(txBuffer), 0);
      Serial.println(F("Packet queued"));
      digitalWrite(BUILTIN_LED, HIGH);
    }
    else
    {
      //try again in 3 seconds
      os_setTimedCallback(&sendjob, os_getTime() + sec2osticks(3), do_send);
    }
  }
  // Next TX is scheduled after TX_COMPLETE event.
}

void setup() {
  Serial.begin(115200);
  Serial.println(F("TTN Mapper"));
  /* Start power controller */
  Wire.begin(21, 22);
  Serial.println("Starting AXP192 power controller");
  if (!axp.begin(Wire, AXP192_SLAVE_ADDRESS)) {
    Serial.println("AXP192 started");
  } else {
    Serial.println("AXP192 failed");
  }
  axp.setPowerOutPut(AXP192_LDO2, AXP202_ON);  // Lora on T-Beam V1.x
  axp.setPowerOutPut(AXP192_LDO3, AXP202_ON);  // Gps on T-Beam V1.x
  axp.setPowerOutPut(AXP192_DCDC2, AXP202_ON);
  axp.setPowerOutPut(AXP192_EXTEN, AXP202_ON);
  axp.setPowerOutPut(AXP192_DCDC1, AXP202_ON); // OLED on T-Beam v1.x
  axp.setDCDC1Voltage(3300);
  axp.setChgLEDMode(AXP20X_LED_BLINK_1HZ);
  axp.adc1Enable(AXP202_BATT_CUR_ADC1, 1);

  //Turn off WiFi and Bluetooth
  WiFi.mode(WIFI_OFF);
  btStop();
  gps.init();

  // LMIC init
  os_init();
  // Reset the MAC state. Session and pending data transfers will be discarded.
  LMIC_reset();


#ifdef USE_OTAA
  esp_reset_reason_t reason = esp_reset_reason();
  if ((reason == ESP_RST_DEEPSLEEP) || (reason == ESP_RST_SW))
  {
    LMIC_setSession(0x1, otaaDevAddr, otaaNetwKey, otaaApRtKey);
  }
#else // ABP
  LMIC_setSession (0x1, DEVADDR, NWKSKEY, APPSKEY);

  // TTN uses SF9 for its RX2 window.
  LMIC.dn2Dr = DR_SF9;

  // Disable link check validation
  LMIC_setLinkCheckMode(0);
#endif

  // This must be done AFTER calling LMIC_setSession !
  setOrRestorePersistentCounters();

#ifdef CFG_eu868
  LMIC_setupChannel(0, 868100000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band
  LMIC_setupChannel(1, 868300000, DR_RANGE_MAP(DR_SF12, DR_SF7B), BAND_CENTI);      // g-band
  LMIC_setupChannel(2, 868500000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band
  LMIC_setupChannel(3, 867100000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band
  LMIC_setupChannel(4, 867300000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band
  LMIC_setupChannel(5, 867500000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band
  LMIC_setupChannel(6, 867700000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band
  LMIC_setupChannel(7, 867900000, DR_RANGE_MAP(DR_SF12, DR_SF7),  BAND_CENTI);      // g-band
  LMIC_setupChannel(8, 868800000, DR_RANGE_MAP(DR_FSK,  DR_FSK),  BAND_MILLI);      // g2-band
#endif

#ifdef CFG_us915
  LMIC_selectSubBand(1);

  //Disable FSB2-8, channels 16-72
  for (int i = 16; i < 73; i++) {
    if (i != 10)
      LMIC_disableChannel(i);
  }
#endif

  // Set data rate and transmit power for uplink (note: txpow seems to be ignored by the library)
  LMIC_setDrTxpow(DR_SF7, 14);

  do_send(&sendjob);
  pinMode(BUILTIN_LED, OUTPUT);
  digitalWrite(BUILTIN_LED, LOW);

}

void loop() {
  os_runloop_once();
}

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// If you are in USA on a 915Mhz network instead of an european / 868 Mhz one,

// you MUST modify the arduino lmic library "config.h" to enable CFG_us915 instead of CFG_eu868.

// That "config.h" should be in the same folder as the "lmic.h" file in your arduino folders.

#include <lmic.h>

#include <hal/hal.h>

// UPDATE our "device_config.h" file in the same folder WITH YOUR TTN KEYS AND ADDR.

#include "device_config.h"

#include "gps.h"

#include <WiFi.h>

#include <esp_sleep.h>

#include "axp20x.h"

AXP20X_Class axp;

// T-Beam specific hardware

#undef BUILTIN_LED

#define BUILTIN_LED 21

char s[32]; // used to sprintf for Serial output

uint8_t txBuffer[10];

gps gps;

static osjob_t sendjob;

// Those variables keep their values after software restart or wakeup from sleep, not after power loss or hard reset !

RTC_NOINIT_ATTR int RTCseqnoUp, RTCseqnoDn;

#ifdef USE_OTAA

RTC_NOINIT_ATTR u4_t otaaDevAddr;

RTC_NOINIT_ATTR u1_t otaaNetwKey[16];

RTC_NOINIT_ATTR u1_t otaaApRtKey[16];

#endif

// Schedule TX every this many seconds (might become longer due to duty cycle limitations).

const unsigned TX_INTERVAL = 120;

// Pin mapping for TBeams, might not suit the latest version > 1.0 ?

const lmic_pinmap lmic_pins = {

.nss = 18,

.rxtx = LMIC_UNUSED_PIN,

.rst = LMIC_UNUSED_PIN, // was "14,"

.dio = {26, 33, 32},

};

// These callbacks are only used in over-the-air activation.

#ifdef USE_OTAA

void os_getDevEui (u1_t* buf) {

memcpy_P(buf, DEVEUI, 8);

}

void os_getArtEui (u1_t* buf) {

memcpy_P(buf, APPEUI, 8);

}

void os_getDevKey (u1_t* buf) {

memcpy_P(buf, APPKEY, 16);

}

#else

void os_getArtEui (u1_t* buf) { }

void os_getDevEui (u1_t* buf) { }

void os_getDevKey (u1_t* buf) { }

#endif

void storeFrameCounters()

{

RTCseqnoUp = LMIC.seqnoUp;

RTCseqnoDn = LMIC.seqnoDn;

sprintf(s, "Counters stored as %d/%d", LMIC.seqnoUp, LMIC.seqnoDn);

Serial.println(s);

}

void restoreFrameCounters()

{

LMIC.seqnoUp = RTCseqnoUp;

LMIC.seqnoDn = RTCseqnoDn;

sprintf(s, "Restored counters as %d/%d", LMIC.seqnoUp, LMIC.seqnoDn);

Serial.println(s);

}

void setOrRestorePersistentCounters()

{

esp_reset_reason_t reason = esp_reset_reason();

if ((reason != ESP_RST_DEEPSLEEP) && (reason != ESP_RST_SW))

{

Serial.println(F("Counters both set to 0"));

LMIC.seqnoUp = 0;

LMIC.seqnoDn = 0;

}

else

{

restoreFrameCounters();

}

void onEvent (ev_t ev) {

switch (ev) {

case EV_SCAN_TIMEOUT:

Serial.println(F("EV_SCAN_TIMEOUT"));

break;

case EV_BEACON_FOUND:

Serial.println(F("EV_BEACON_FOUND"));

break;

case EV_BEACON_MISSED:

Serial.println(F("EV_BEACON_MISSED"));

break;

case EV_BEACON_TRACKED:

Serial.println(F("EV_BEACON_TRACKED"));

break;

case EV_JOINING:

Serial.println(F("EV_JOINING"));

break;

case EV_JOINED:

Serial.println(F("EV_JOINED"));

#ifdef USE_OTAA

otaaDevAddr = LMIC.devaddr;

memcpy_P(otaaNetwKey, LMIC.nwkKey, 16);

memcpy_P(otaaApRtKey, LMIC.artKey, 16);

sprintf(s, "got devaddr = 0x%X", LMIC.devaddr);

Serial.println(s);

#endif

// Disable link check validation (automatically enabled

// during join, but not supported by TTN at this time).

LMIC_setLinkCheckMode(0);

// TTN uses SF9 for its RX2 window.

LMIC.dn2Dr = DR_SF9;

break;

case EV_RFU1:

Serial.println(F("EV_RFU1"));

break;

case EV_JOIN_FAILED:

Serial.println(F("EV_JOIN_FAILED"));

break;

case EV_REJOIN_FAILED:

Serial.println(F("EV_REJOIN_FAILED"));

break;

case EV_TXCOMPLETE:

Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)"));

digitalWrite(BUILTIN_LED, LOW);

if (LMIC.txrxFlags & TXRX_ACK) {

Serial.println(F("Received Ack"));

}

if (LMIC.dataLen) {

sprintf(s, "Received %i bytes of payload", LMIC.dataLen);

Serial.println(s);

sprintf(s, "RSSI %d SNR %.1d", LMIC.rssi, LMIC.snr);

Serial.println(s);

}

storeFrameCounters();

// Schedule next transmission

Serial.println("Good night...");

axp.setChgLEDMode(AXP20X_LED_OFF);

axp.setPowerOutPut(AXP192_LDO2, AXP202_OFF);

axp.setPowerOutPut(AXP192_LDO3, AXP202_OFF);

axp.setPowerOutPut(AXP192_DCDC2, AXP202_OFF);

axp.setPowerOutPut(AXP192_DCDC1, AXP202_OFF);

axp.setPowerOutPut(AXP192_EXTEN, AXP202_OFF);

delay(20);

esp_sleep_enable_timer_wakeup(TX_INTERVAL * 1000000);

esp_deep_sleep_start();

do_send(&sendjob);

break;

case EV_LOST_TSYNC:

Serial.println(F("EV_LOST_TSYNC"));

break;

case EV_RESET:

Serial.println(F("EV_RESET"));

break;

case EV_RXCOMPLETE:

// data received in ping slot

Serial.println(F("EV_RXCOMPLETE"));

break;

case EV_LINK_DEAD:

Serial.println(F("EV_LINK_DEAD"));

break;

case EV_LINK_ALIVE:

Serial.println(F("EV_LINK_ALIVE"));

break;

default:

Serial.println(F("Unknown event"));

break;

}

void do_send(osjob_t* j) {

// Check if there is not a current TX/RX job running

if (LMIC.opmode & OP_TXRXPEND)

{

Serial.println(F("OP_TXRXPEND, not sending"));

}

else

{

if (gps.checkGpsFix())

{

// Prepare upstream data transmission at the next possible time.

gps.buildPacket(txBuffer);

LMIC_setTxData2(1, txBuffer, sizeof(txBuffer), 0);

Serial.println(F("Packet queued"));

digitalWrite(BUILTIN_LED, HIGH);

}

else

{

//try again in 3 seconds

os_setTimedCallback(&sendjob, os_getTime() + sec2osticks(3), do_send);

}

// Next TX is scheduled after TX_COMPLETE event.

}

void setup() {

Serial.begin(115200);

Serial.println(F("TTN Mapper"));

/* Start power controller */

Wire.begin(21, 22);

Serial.println("Starting AXP192 power controller");

if (!axp.begin(Wire, AXP192_SLAVE_ADDRESS)) {

Serial.println("AXP192 started");

} else {

Serial.println("AXP192 failed");

}

axp.setPowerOutPut(AXP192_LDO2, AXP202_ON); // Lora on T-Beam V1.x

axp.setPowerOutPut(AXP192_LDO3, AXP202_ON); // Gps on T-Beam V1.x

axp.setPowerOutPut(AXP192_DCDC2, AXP202_ON);

axp.setPowerOutPut(AXP192_EXTEN, AXP202_ON);

axp.setPowerOutPut(AXP192_DCDC1, AXP202_ON); // OLED on T-Beam v1.x

axp.setDCDC1Voltage(3300);

axp.setChgLEDMode(AXP20X_LED_BLINK_1HZ);

axp.adc1Enable(AXP202_BATT_CUR_ADC1, 1);

//Turn off WiFi and Bluetooth

WiFi.mode(WIFI_OFF);

btStop();

gps.init();

// LMIC init

os_init();

// Reset the MAC state. Session and pending data transfers will be discarded.

LMIC_reset();

#ifdef USE_OTAA

esp_reset_reason_t reason = esp_reset_reason();

if ((reason == ESP_RST_DEEPSLEEP) || (reason == ESP_RST_SW))

{

LMIC_setSession(0x1, otaaDevAddr, otaaNetwKey, otaaApRtKey);

}

#else // ABP

LMIC_setSession (0x1, DEVADDR, NWKSKEY, APPSKEY);

// TTN uses SF9 for its RX2 window.

LMIC.dn2Dr = DR_SF9;

// Disable link check validation

LMIC_setLinkCheckMode(0);

#endif

// This must be done AFTER calling LMIC_setSession !

setOrRestorePersistentCounters();

#ifdef CFG_eu868

LMIC_setupChannel(0, 868100000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band

LMIC_setupChannel(1, 868300000, DR_RANGE_MAP(DR_SF12, DR_SF7B), BAND_CENTI); // g-band

LMIC_setupChannel(2, 868500000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band

LMIC_setupChannel(3, 867100000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band

LMIC_setupChannel(4, 867300000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band

LMIC_setupChannel(5, 867500000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band

LMIC_setupChannel(6, 867700000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band

LMIC_setupChannel(7, 867900000, DR_RANGE_MAP(DR_SF12, DR_SF7), BAND_CENTI); // g-band

LMIC_setupChannel(8, 868800000, DR_RANGE_MAP(DR_FSK, DR_FSK), BAND_MILLI); // g2-band

#endif

#ifdef CFG_us915

LMIC_selectSubBand(1);

//Disable FSB2-8, channels 16-72

for (int i = 16; i < 73; i++) {

if (i != 10)

LMIC_disableChannel(i);

}

#endif

// Set data rate and transmit power for uplink (note: txpow seems to be ignored by the library)

LMIC_setDrTxpow(DR_SF7, 14);

do_send(&sendjob);

pinMode(BUILTIN_LED, OUTPUT);

digitalWrite(BUILTIN_LED, LOW);

}

void loop() {

os_runloop_once();

}

gps.h

#pragma once


#include <TinyGPS++.h>
#include <HardwareSerial.h>

#define GPS_TX 34
#define GPS_RX 12

class gps
{
    public:
        void init();
        bool checkGpsFix();
        void buildPacket(uint8_t txBuffer[10]);
        void encode();

    private:
        uint32_t LatitudeBinary, LongitudeBinary;
        uint16_t altitudeGps;
        uint8_t hdopGps;
        uint8_t sats;
        char t[32]; // used to sprintf for Serial output
        TinyGPSPlus tGps;
};

#pragma once

#include <TinyGPS++.h>

#include <HardwareSerial.h>

#define GPS_TX 34

#define GPS_RX 12

class gps

{

public:

void init();

bool checkGpsFix();

void buildPacket(uint8_t txBuffer[10]);

void encode();

private:

uint32_t LatitudeBinary, LongitudeBinary;

uint16_t altitudeGps;

uint8_t hdopGps;

uint8_t sats;

char t[32]; // used to sprintf for Serial output

TinyGPSPlus tGps;

};

gps.cpp

#include "gps.h"

HardwareSerial GPSSerial(1);

void gps::init()
{
  GPSSerial.begin(9600, SERIAL_8N1, GPS_TX, GPS_RX);
  GPSSerial.setTimeout(2);
}

void gps::encode()
{       
    int data;
    int previousMillis = millis();

    while((previousMillis + 1000) > millis())
    {
        while (GPSSerial.available() )
        {
            char data = GPSSerial.read();
            tGps.encode(data);
            //Serial.print(data);
        }
    }
     //Serial.println("");
}

void gps::buildPacket(uint8_t txBuffer[10])
{
  LatitudeBinary = ((tGps.location.lat() + 90) / 180.0) * 16777215;
  LongitudeBinary = ((tGps.location.lng() + 180) / 360.0) * 16777215;
  
  sprintf(t, "Lat: %f", tGps.location.lat());
  Serial.println(t);
  
  sprintf(t, "Lng: %f", tGps.location.lng());
  Serial.println(t);
  
  txBuffer[0] = ( LatitudeBinary >> 16 ) & 0xFF;
  txBuffer[1] = ( LatitudeBinary >> 8 ) & 0xFF;
  txBuffer[2] = LatitudeBinary & 0xFF;

  txBuffer[3] = ( LongitudeBinary >> 16 ) & 0xFF;
  txBuffer[4] = ( LongitudeBinary >> 8 ) & 0xFF;
  txBuffer[5] = LongitudeBinary & 0xFF;

  altitudeGps = tGps.altitude.meters();
  txBuffer[6] = ( altitudeGps >> 8 ) & 0xFF;
  txBuffer[7] = altitudeGps & 0xFF;

  hdopGps = tGps.hdop.value()/10;
  txBuffer[8] = hdopGps & 0xFF;

  sats = tGps.satellites.value();
  txBuffer[9] = sats & 0xFF;
}

bool gps::checkGpsFix()
{
  encode();
  if (tGps.location.isValid() && 
      tGps.location.age() < 2000 &&
      tGps.hdop.isValid() &&
      tGps.hdop.value() <= 300 &&
      tGps.hdop.age() < 2000 &&
      tGps.altitude.isValid() && 
      tGps.altitude.age() < 2000 )
  {
    Serial.println("Valid gps Fix.");
    return true;
  }
  else
  {
    Serial.println("No gps Fix.");
    return false;
  }
}

#include "gps.h"

HardwareSerial GPSSerial(1);

void gps::init()

{

GPSSerial.begin(9600, SERIAL_8N1, GPS_TX, GPS_RX);

GPSSerial.setTimeout(2);

}

void gps::encode()

{

int data;

int previousMillis = millis();

while((previousMillis + 1000) > millis())

{

while (GPSSerial.available() )

{

char data = GPSSerial.read();

tGps.encode(data);

//Serial.print(data);

}

//Serial.println("");

}

void gps::buildPacket(uint8_t txBuffer[10])

{

LatitudeBinary = ((tGps.location.lat() + 90) / 180.0) * 16777215;

LongitudeBinary = ((tGps.location.lng() + 180) / 360.0) * 16777215;

sprintf(t, "Lat: %f", tGps.location.lat());

Serial.println(t);

sprintf(t, "Lng: %f", tGps.location.lng());

Serial.println(t);

txBuffer[0] = ( LatitudeBinary >> 16 ) & 0xFF;

txBuffer[1] = ( LatitudeBinary >> 8 ) & 0xFF;

txBuffer[2] = LatitudeBinary & 0xFF;

txBuffer[3] = ( LongitudeBinary >> 16 ) & 0xFF;

txBuffer[4] = ( LongitudeBinary >> 8 ) & 0xFF;

txBuffer[5] = LongitudeBinary & 0xFF;

altitudeGps = tGps.altitude.meters();

txBuffer[6] = ( altitudeGps >> 8 ) & 0xFF;

txBuffer[7] = altitudeGps & 0xFF;

hdopGps = tGps.hdop.value()/10;

txBuffer[8] = hdopGps & 0xFF;

sats = tGps.satellites.value();

txBuffer[9] = sats & 0xFF;

}

bool gps::checkGpsFix()

{

encode();

if (tGps.location.isValid() &&

tGps.location.age() < 2000 &&

tGps.hdop.isValid() &&

tGps.hdop.value() <= 300 &&

tGps.hdop.age() < 2000 &&

tGps.altitude.isValid() &&

tGps.altitude.age() < 2000 )

{

Serial.println("Valid gps Fix.");

return true;

}

else

{

Serial.println("No gps Fix.");

return false;

}

device_config.h (your OTAA secrets can be copied from the TTN Console (note msb/lsb!)

#pragma once


// uncomment to use OTAA instead of ABP
#define USE_OTAA 1 // so provide your DEVEUI, APPEUI and APPKEY below


// UPDATE WITH YOUR DEVICE TTN SECRETS
#ifdef USE_OTAA
static PROGMEM u1_t DEVEUI[8]  = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; // Device EUI, hex, lsb
static PROGMEM u1_t APPEUI[8]  = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; // Application EUI, hex, lsb
static PROGMEM u1_t APPKEY[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0 }; // App Key, hex, msb
#else
static PROGMEM u1_t NWKSKEY[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; // LoRaWAN NwkSKey, network session key, hex, msb
static PROGMEM u1_t APPSKEY[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; // LoRaWAN AppSKey, application session key, hex, msb
static PROGMEM u4_t DEVADDR = 0x00000000 ; // LoRaWAN end-device address (DevAddr), hex, msb
#endif

#pragma once

// uncomment to use OTAA instead of ABP

#define USE_OTAA 1 // so provide your DEVEUI, APPEUI and APPKEY below

// UPDATE WITH YOUR DEVICE TTN SECRETS

#ifdef USE_OTAA

static PROGMEM u1_t DEVEUI[8] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; // Device EUI, hex, lsb

static PROGMEM u1_t APPEUI[8] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; // Application EUI, hex, lsb

static PROGMEM u1_t APPKEY[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0 }; // App Key, hex, msb

#else

static PROGMEM u1_t NWKSKEY[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; // LoRaWAN NwkSKey, network session key, hex, msb

static PROGMEM u1_t APPSKEY[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; // LoRaWAN AppSKey, application session key, hex, msb

static PROGMEM u4_t DEVADDR = 0x00000000 ; // LoRaWAN end-device address (DevAddr), hex, msb

#endif

^**Payload Format decoder (javascript to be entered at the Payload Formats tab of the TTN Console; reverses the encoding as performed by function buildPacket() in gps.cpp)

function Decoder(bytes, port) {
    var decoded = {};

    decoded.latitude = ((bytes[0]<<16)>>>0) + ((bytes[1]<<8)>>>0) + bytes[2];
    decoded.latitude = (decoded.latitude / 16777215.0 * 180) - 90;
  
    decoded.longitude = ((bytes[3]<<16)>>>0) + ((bytes[4]<<8)>>>0) + bytes[5];
    decoded.longitude = (decoded.longitude / 16777215.0 * 360) - 180;
  
    var altValue = ((bytes[6]<<8)>>>0) + bytes[7];
    var sign = bytes[6] & (1 << 7);
    if(sign)
    {
        decoded.altitude = 0xFFFF0000 | altValue;
    }
    else
    {
        decoded.altitude = altValue;
    }
  
    decoded.hdop = bytes[8] / 10.0;
    decoded.sats = bytes[9];

    return decoded;
}

function Decoder(bytes, port) {

var decoded = {};

decoded.latitude = ((bytes[0]<<16)>>>0) + ((bytes[1]<<8)>>>0) + bytes[2];

decoded.latitude = (decoded.latitude / 16777215.0 * 180) - 90;

decoded.longitude = ((bytes[3]<<16)>>>0) + ((bytes[4]<<8)>>>0) + bytes[5];

decoded.longitude = (decoded.longitude / 16777215.0 * 360) - 180;

var altValue = ((bytes[6]<<8)>>>0) + bytes[7];

var sign = bytes[6] & (1 << 7);

if(sign)

{

decoded.altitude = 0xFFFF0000 | altValue;

}

else

{

decoded.altitude = altValue;

}

decoded.hdop = bytes[8] / 10.0;

decoded.sats = bytes[9];

return decoded;

}

Category: LoRaWan

Self-Hosted GPS Tracker

TTGO T-Beam