GPSTRACK

This is a front-end application for a LoRaWAN GPS tracker.

The GPS location, battery voltage and temperature are measured by a Sodaq One and send to The Things Network. The Sodaq is running the universal tracker firmware.

The data is converted on the TTN backend using the following converter

function Decoder(bytes, port) {
  // Decode an uplink message from a buffer (array) of bytes to an object of fields.
  // see http://forum.sodaq.com/t/interpreting-payload-data-from-the-sodaqone-universaltracker/374/11

var epoch = (bytes[3] << 24) | (bytes[2] << 16) | (bytes[1] << 8) | bytes[0];
var batt = (3000+10*bytes[4])/1000;
var temp = bytes[5];
var lat = (bytes[9] << 24) | (bytes[8] << 16) | (bytes[7] << 8) | bytes[6];
var lon = (bytes[13] << 24) | (bytes[12] << 16) | (bytes[11] << 8) | bytes[10];
var alt = (bytes[15] << 8) | bytes[14];
var speed = (bytes[17] << 8) | bytes[16];
var course = bytes[18];
var sats = bytes[19];
var ttf = bytes[20];

  return {
    course: course,
    satellites: sats,
    time_to_fix: ttf,
    latitude: lat,
    longitude: lon,
    epoch: epoch,
    battery: batt,
    speed: speed,
    temperature: temp
  };
}

The backend sends the json-formatted data to the "TTN Data Storage" integration service, where it is retained for 7 days.

This repository contains the node.js code that reads the data from "TTN Data Storage" and visualizes on on a web page.