A nice feature of the Philips Hue lamps is called Geofencing. This just means that you can instruct the Hue bridge to automatically switch your lights on when you are approaching your house. So for a time I wondered how they do that. And in fact it is very easy.
It is a technique that can be used for many different purposes. Not only to test if you are around but this also makes it possible to test whether your wireless apparatus are actually functioning. It’s called ping.
Since we often have our cell/mobile phone with is, an inexpensive ESP8266 can be set up to look for the phone Internet address come into range.
Luc has Arduino code for for the project and notes it is very flexible as to what you can do once a detection is made.
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