LoRaWAN Setup Guide

This guide covers connecting your Wireless Tracker to LoRaWAN networks including The Things Network (TTN), SnapEmu, and other LoRaWAN servers.

Prerequisites

• Heltec Wireless Tracker with LoRa antenna
• Gateway coverage in your area (or your own gateway)
• Account on your chosen LoRaWAN network server
• Arduino IDE or PlatformIO with Heltec libraries

Regional Frequencies

Choose the correct model for your region:

Region	Frequency	Model
EU868	863-870 MHz	Wireless Tracker-HF
US915	902-928 MHz	Wireless Tracker-HF
AU915	915-928 MHz	Wireless Tracker-HF
AS923	920-925 MHz	Wireless Tracker-HF
KR920	920-923 MHz	Wireless Tracker-HF
CN470	470-510 MHz	Wireless Tracker-LF

Caution

Using the wrong frequency band is illegal in most jurisdictions. Verify your local regulations before transmitting.

OTAA vs ABP

Method	Pros	Cons
OTAA (Over-The-Air Activation)	More secure, automatic session renewal	Requires join process
ABP (Activation By Personalization)	Immediate transmission	Less secure, manual key management

Tip

OTAA is recommended for most applications. Use ABP only when join latency is unacceptable.

Network Registration

The Things Network

Register on TTN

1. Create account at thethingsnetwork.org

2. Create a new Application

3. Add an End Device:

   • Select “Enter end device specifics manually”
   • Frequency plan: Match your region (e.g., US915 FSB2)
   • LoRaWAN version: 1.0.3
   • Regional Parameters: RP001 Regional Parameters 1.0.3 revision A

4. Generate credentials:

   • DevEUI: Generate or use chip’s MAC
   • AppEUI: All zeros or generate
   • AppKey: Generate (save this!)

5. Copy credentials for firmware

TTN Payload Decoder

function decodeUplink(input) {
    return {
        data: {
            // Parse your payload format here
            battery: input.bytes[0] / 10,
            latitude: ((input.bytes[1] << 24) | (input.bytes[2] << 16) |
                      (input.bytes[3] << 8) | input.bytes[4]) / 1000000,
            longitude: ((input.bytes[5] << 24) | (input.bytes[6] << 16) |
                       (input.bytes[7] << 8) | input.bytes[8]) / 1000000
        },
        warnings: [],
        errors: []
    };
}

SnapEmu

Register on SnapEmu

1. Create account at snapemu.com

2. Configure your Heltec gateway to connect to SnapEmu

3. Add a new Node Device

4. Copy the generated credentials:

   • DevEUI
   • AppEUI
   • AppKey

SnapEmu Features

• Automatic device provisioning for Heltec devices
• Built-in decoder library
• Real-time data visualization
• Historical data storage

Firmware Configuration

Basic LoRaWAN Example

#include "LoRaWan_APP.h"

// OTAA Credentials - Replace with your values
uint8_t devEui[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
uint8_t appEui[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
uint8_t appKey[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };

// Channel mask for US915 FSB2 (channels 8-15)
uint16_t userChannelsMask[6] = { 0xFF00, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000 };

// For EU868, use:
// uint16_t userChannelsMask[6] = { 0x00FF, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000 };

LoRaMacRegion_t loraWanRegion = LORAMAC_REGION_US915;  // Change for your region
DeviceClass_t loraWanClass = CLASS_A;
uint32_t appTxDutyCycle = 60000;  // 60 second transmit interval
bool overTheAirActivation = true;
bool loraWanAdr = true;
bool isTxConfirmed = true;
uint8_t appPort = 1;
uint8_t confirmedNbTrials = 4;

void setup() {
    Serial.begin(115200);
    Mcu.begin(HELTEC_BOARD, SLOW_CLK_TPYE);

    LoRaWAN.init(loraWanClass, loraWanRegion);
    LoRaWAN.setDefaultDR(3);  // SF7-SF12 depending on region
}

static void prepareTxFrame(uint8_t port) {
    appDataSize = 4;

    // Example: Send battery voltage and status
    float voltage = readBatteryVoltage();
    uint16_t vBat = (uint16_t)(voltage * 100);

    appData[0] = (uint8_t)(vBat >> 8);
    appData[1] = (uint8_t)(vBat & 0xFF);
    appData[2] = 0x00;  // Status byte
    appData[3] = 0x00;  // Reserved
}

void loop() {
    switch (deviceState) {
        case DEVICE_STATE_INIT:
            LoRaWAN.init(loraWanClass, loraWanRegion);
            deviceState = DEVICE_STATE_JOIN;
            break;

        case DEVICE_STATE_JOIN:
            LoRaWAN.join();
            break;

        case DEVICE_STATE_SEND:
            prepareTxFrame(appPort);
            LoRaWAN.send();
            deviceState = DEVICE_STATE_CYCLE;
            break;

        case DEVICE_STATE_CYCLE:
            txDutyCycleTime = appTxDutyCycle +
                randr(-APP_TX_DUTYCYCLE_RND, APP_TX_DUTYCYCLE_RND);
            LoRaWAN.cycle(txDutyCycleTime);
            deviceState = DEVICE_STATE_SLEEP;
            break;

        case DEVICE_STATE_SLEEP:
            LoRaWAN.sleep(loraWanClass);
            break;

        default:
            deviceState = DEVICE_STATE_INIT;
            break;
    }
}

float readBatteryVoltage() {
    pinMode(2, OUTPUT);
    digitalWrite(2, LOW);
    int raw = analogRead(1);
    digitalWrite(2, HIGH);
    return (raw / 4095.0) * 3.3 * 4.9;
}

Region Configuration

Region	LoRaMacRegion_t	Default DR	Notes
EU868	LORAMAC_REGION_EU868	DR5 (SF7)	1% duty cycle
US915	LORAMAC_REGION_US915	DR3 (SF7)	Use FSB2 for TTN
AU915	LORAMAC_REGION_AU915	DR3 (SF7)	Similar to US915
AS923	LORAMAC_REGION_AS923	DR5 (SF7)	Multiple sub-bands
CN470	LORAMAC_REGION_CN470	DR3 (SF7)	LF model only

Sending GPS Data

#include "TinyGPS++.h"

TinyGPSPlus gps;
HardwareSerial GPSSerial(1);

void setup() {
    // Enable GNSS power (V1.1)
    pinMode(3, OUTPUT);
    digitalWrite(3, HIGH);

    // Initialize GNSS serial
    GPSSerial.begin(115200, SERIAL_8N1, 33, 34);
}

static void prepareTxFrame(uint8_t port) {
    // Read latest GPS data
    while (GPSSerial.available()) {
        gps.encode(GPSSerial.read());
    }

    if (gps.location.isValid()) {
        int32_t lat = gps.location.lat() * 1000000;
        int32_t lon = gps.location.lng() * 1000000;

        appDataSize = 9;

        // Latitude (4 bytes, big-endian)
        appData[0] = (lat >> 24) & 0xFF;
        appData[1] = (lat >> 16) & 0xFF;
        appData[2] = (lat >> 8) & 0xFF;
        appData[3] = lat & 0xFF;

        // Longitude (4 bytes, big-endian)
        appData[4] = (lon >> 24) & 0xFF;
        appData[5] = (lon >> 16) & 0xFF;
        appData[6] = (lon >> 8) & 0xFF;
        appData[7] = lon & 0xFF;

        // Satellites
        appData[8] = gps.satellites.value();
    }
}

Troubleshooting

Join Failures

Symptom	Cause	Solution
No join accept	Wrong credentials	Double-check DevEUI, AppEUI, AppKey
Timeout	No gateway	Verify gateway coverage
Repeated joins	Session expired	Check network server settings

No Uplinks Received

1. Verify antenna is connected
2. Check frequency plan matches gateway
3. Increase spreading factor (lower DR) for better range
4. Monitor RSSI/SNR on gateway

Duty Cycle Exceeded

EU868 has strict 1% duty cycle limits:

// Increase transmit interval to respect duty cycle
uint32_t appTxDutyCycle = 300000;  // 5 minutes minimum for EU868

References

• LoRaWAN Specification
• Heltec LoRaWAN Examples
• TTN Device Registration