Intro

This is a simple sketch demonstrating the capability of the TTGO T-Beam as a TTN Mapper Node on The Things Network LoraWAN.

Derived from sbiermann/Lora-TTNMapper-ESP32 and with some information/inspiration from cyberman54/ESP32-Paxcounter and Edzelf/LoRa.

Forked from DeuxVis/Lora-TTNMapper-T-Beam and added Deep Sleep option + a check if there is any movement. If not, updates are only sent every 5 minutes instead of every 30 seconds.

Software dependencies

Arduino IDE ESP32 extension

TinyGPS++

LMIC-Arduino : Make sure to get the last version - 1.5.0+arduino-2 currently - because the arduino IDE library updater is getting confused by the versioning scheme of that library.

Instructions

You need to connect the T-Beam DIO1 pin marked Lora1 to the pin 33 - So that the ESP32 can read that output from the Lora module. Optionally you can also connect the Lora2 output to GPIO 32, but this is not needed here.

You can program the T-Beam using the Arduino ESP32 board 'Heltec_WIFI_LoRa_32'.

On The Things Network side, the settings needed are available here.

Configure the Payload decoder with:

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;

    return decoded;
}

Let me know if more detailed instructions are needed.

Todolist

• Stop sending data to TTN until the GPS get a fix. <== Done thanks to @Roeland54
• Manage and document the different T-Beam revisions/versions.
• Switch to OTAA auth method for TTN and save the 'credentials' for reboot use.