Is this the smartest personal tracking device yet? The new pocket-sized Trax GPS tracker enables the user to be located via an IOS or Android smartphone app or a computer – in real time. Apparently, it can be programmed to set a boundary (or Geo fence) so that if your child or pet wander beyond a predetermined area, an alert is sent to your phone. According to various blurb, it then guides you towards the child or pet using augmented reality: using the phone’s camera viewpoint, you simply follow the onscreen directions and, voila, panic over. They say it's accurate to around 1.5 metres and will run for about four days on a single charge. Waterproof too. The Trax comes with a SIM card that allows two years of free data and roaming in 28 countries; thereafter the fee is around £3 per month. The Trax retails at around £170 and looks to us like a handy piece of kit for families with kids and pets, skiers, mountaineers, hikers, old folk with poor memory and, well, anyone who gets lost a lot.