udp-server.rb

require 'socket'
s = UDPSocket.new
s.bind(nil, 43333)

while(true) do
  text, sender = s.recvfrom(39)
  puts
  71.times{print "="} 
  puts
  puts "Received message from " + sender[3].to_s + ":" + sender[1].to_s
  
  raw = text.unpack('H*')[0].to_str

  if raw.length != 78
    puts "Message received had the wrong length (" + raw.length.to_s + ", expecting 78)!"
    puts raw
    s.send([0].pack('N'), 0, sender[3], sender[1])
    next
  end

  puts "c  ts       lat      lng      spd  hdg  alt  acc  batt uuid"
  print raw[0,2], " ", raw[2,8], " ", raw[10,8], " ", raw[18,8], " ", raw[26,4], " ", raw[30,4], " ", raw[34,4], " ", raw[38,4], " ", raw[42,4], " ", raw[46,32]
  puts

  date = text[1,4].unpack('N')[0]
  latitude = text[5,4].unpack('N')[0]
  longitude = text[9,4].unpack('N')[0]
  speed = text[13,2].unpack('n')[0]
  heading = text[15,2].unpack('n')[0]
  altitude = text[17,2].unpack('n')[0]
  accuracy = text[19,2].unpack('n')[0]
  battery = text[21,2].unpack('n')[0]
  uuid = text[23,16].unpack('H*')[0]

  print "Date: ", date, " ("
  print Time.at(date)
  print ")"
  puts

  print "Location: "
  print (((latitude / 4294967296.0) * 180.0) - 90.0)
  print ", "
  print (((longitude / 4294967296.0) * 360.0) - 180.0)
  puts
  
  print "Speed: ", speed, "km/h  "
  print "Heading: ", heading, "deg  "
  print "Altitude: ", altitude, "m  "
  print "Accuracy: ", accuracy, "m  "
  print "Battery: ", battery, "%  "
  puts
  
  print "UUID: ", uuid
  puts
  
  s.send([date].pack('N'), 0, sender[3], sender[1])
  
end