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project:lora_nodes

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LoRa TTN node setup

Arduino and ESP32 support

The Things Network account

Create TTN account

Go to TTN Applications

Register Device

Example code

Download example and install missing libraries

otaa_example.ino
#include <lmic.h>
#include <hal/hal.h>
#include <SPI.h>
#include <U8x8lib.h>
 
#define BUILTIN_LED 25
 
// the OLED used
U8X8_SSD1306_128X64_NONAME_SW_I2C u8x8(/* clock=*/ 15, /* data=*/ 4, /* reset=*/ 16);
 
// This EUI must be in little-endian format, so least-significant-byte
// first. When copying an EUI from ttnctl output, this means to reverse
// the bytes. For TTN issued EUIs the last bytes should be 0xD5, 0xB3,
// 0x70.
static const u1_t PROGMEM APPEUI[8]={ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
void os_getArtEui (u1_t* buf) {
  memcpy_P(buf, APPEUI, 8);
}
 
// This should also be in little endian format, see above.
static const u1_t PROGMEM DEVEUI[8]={ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
void os_getDevEui (u1_t* buf) {
  memcpy_P(buf, DEVEUI, 8);
}
 
// This key should be in big endian format (or, since it is not really a
// number but a block of memory, endianness does not really apply). In
// practice, a key taken from ttnctl can be copied as-is.
// The key shown here is the semtech default key.
static const u1_t PROGMEM APPKEY[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
void os_getDevKey (u1_t* buf) {
  memcpy_P(buf, APPKEY, 16);
}
 
static uint8_t mydata[] = "Hi";
static osjob_t sendjob;
 
// Schedule TX every this many seconds (might become longer due to duty
// cycle limitations).
const unsigned TX_INTERVAL = 60;
 
// Pin mapping
const lmic_pinmap lmic_pins = {
  .nss = 18,
  .rxtx = LMIC_UNUSED_PIN,
  .rst = 14,
  .dio = {26, 33, 32},
};
 
void onEvent (ev_t ev) {
  Serial.print(os_getTime());
  u8x8.setCursor(0, 5);
  u8x8.printf("TIME %lu", os_getTime());
  Serial.print(": ");
  switch (ev) {
case EV_SCAN_TIMEOUT:
  Serial.println(F("EV_SCAN_TIMEOUT"));
  u8x8.drawString(0, 7, "EV_SCAN_TIMEOUT");
  break;
case EV_BEACON_FOUND:
  Serial.println(F("EV_BEACON_FOUND"));
  u8x8.drawString(0, 7, "EV_BEACON_FOUND");
  break;
case EV_BEACON_MISSED:
  Serial.println(F("EV_BEACON_MISSED"));
  u8x8.drawString(0, 7, "EV_BEACON_MISSED");
  break;
case EV_BEACON_TRACKED:
  Serial.println(F("EV_BEACON_TRACKED"));
  u8x8.drawString(0, 7, "EV_BEACON_TRACKED");
  break;
case EV_JOINING:
  Serial.println(F("EV_JOINING"));
  u8x8.drawString(0, 7, "EV_JOINING");
  break;
case EV_JOINED:
  Serial.println(F("EV_JOINED"));
  u8x8.drawString(0, 7, "EV_JOINED ");
            LMIC_setDrTxpow(DR_SF12, 14); //added fixed SF after join for longer range messages 
  // Disable link check validation (automatically enabled
  // during join, but not supported by TTN at this time).
  LMIC_setLinkCheckMode(0);
  break;
case EV_RFU1:
  Serial.println(F("EV_RFU1"));
  u8x8.drawString(0, 7, "EV_RFUI");
  break;
case EV_JOIN_FAILED:
  Serial.println(F("EV_JOIN_FAILED"));
  u8x8.drawString(0, 7, "EV_JOIN_FAILED");
  break;
case EV_REJOIN_FAILED:
  Serial.println(F("EV_REJOIN_FAILED"));
  u8x8.drawString(0, 7, "EV_REJOIN_FAILED");
  //break;
  break;
case EV_TXCOMPLETE:
  Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)"));
  u8x8.drawString(0, 7, "EV_TXCOMPLETE");
  digitalWrite(BUILTIN_LED, LOW);
  if (LMIC.txrxFlags & TXRX_ACK) {
    Serial.println(F("Received ack"));
    u8x8.drawString(0, 7, "Received ACK");
  }
  if (LMIC.dataLen) {
    Serial.println(F("Received "));
    u8x8.drawString(0, 6, "RX ");
    Serial.println(LMIC.dataLen);
    u8x8.setCursor(4, 6);
    u8x8.printf("%i bytes", LMIC.dataLen);
    Serial.println(F(" bytes of payload"));
    u8x8.setCursor(0, 7);
    u8x8.printf("RSSI %d SNR %.1d", LMIC.rssi, LMIC.snr);
  }
  // Schedule next transmission
  os_setTimedCallback(&sendjob, os_getTime() + sec2osticks(TX_INTERVAL), do_send);
  break;
case EV_LOST_TSYNC:
  Serial.println(F("EV_LOST_TSYNC"));
  u8x8.drawString(0, 7, "EV_LOST_TSYNC");
  break;
case EV_RESET:
  Serial.println(F("EV_RESET"));
  u8x8.drawString(0, 7, "EV_RESET");
  break;
case EV_RXCOMPLETE:
  // data received in ping slot
  Serial.println(F("EV_RXCOMPLETE"));
  u8x8.drawString(0, 7, "EV_RXCOMPLETE");
  break;
case EV_LINK_DEAD:
  Serial.println(F("EV_LINK_DEAD"));
  u8x8.drawString(0, 7, "EV_LINK_DEAD");
  break;
case EV_LINK_ALIVE:
  Serial.println(F("EV_LINK_ALIVE"));
  u8x8.drawString(0, 7, "EV_LINK_ALIVE");
  break;
default:
  Serial.println(F("Unknown event"));
  u8x8.setCursor(0, 7);
  u8x8.printf("UNKNOWN EVENT %d", ev);
  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"));
u8x8.drawString(0, 7, "OP_TXRXPEND, not sent");
  } else {
// Prepare upstream data transmission at the next possible time.
LMIC_setTxData2(1, mydata, sizeof(mydata) - 1, 0);
Serial.println(F("Packet queued"));
u8x8.drawString(0, 7, "PACKET QUEUED");
digitalWrite(BUILTIN_LED, HIGH);
  }
  // Next TX is scheduled after TX_COMPLETE event.
}
 
void setup() {
 
  Serial.begin(115200);
 
  u8x8.begin();
  u8x8.setFont(u8x8_font_chroma48medium8_r);
  u8x8.drawString(0, 1, "LoRaWAN LMiC");
 
  SPI.begin(5, 19, 27);
 
  // LMIC init
  os_init();
  // Reset the MAC state. Session and pending data transfers will be discarded.
  LMIC_reset();
  LMIC_setDrTxpow(DR_SF12, 14); //set join at SF12 
  // Start job (sending automatically starts OTAA too)
  do_send(&sendjob);
 
  pinMode(BUILTIN_LED, OUTPUT);
  digitalWrite(BUILTIN_LED, LOW);
}
 
void loop() {
  os_runloop_once();
}

Copy EUI & keys from console to code:

  • Device EUI lsb
  • Application EUI lsb
  • App Key msb

Change spreding factor and gain

Spreading Factor (SF #). The higher the SF (i.e. the slower the transmission), the longer the communication range. Large SFs allow longer communication range. However, large SFs also increase the time on air and, consequently, the off-period duration.

Gain? (second number).

Change in all lines!

  • za stacionarni node npr SF12, 14 (veći domet ali i potencijalno više grešaka)
  • za mapiranje iz vožnje SF7, 16 (u zraku je kratko)

LoRa Modem Packet formatting

Upload code and check

Check the received data in console

TTN mapper

TTN mapper služi za prikaz, analizu i mapiranje TTN LoRa mreže. Sučelje mu je u banani pa je najbolje pristupati direktno s parametrima:

Za pristup pojedinom node-u (korigiraj datum):

Za pristup pojedinom gateway-u:

Android aplikacija (korištenje GPS-a telefona i linkanje s LoRa node-om)

project/lora_nodes.1519558727.txt.gz · Last modified: 2018/02/25 12:38 by dp