RogerBW's Blog

When I'm driving, I may get caught in traffic or have to divert round roadworks. If that happens, I don't want to pull in to call whoever's at my destination; that'll just make me even later, and on the motorway there aren't many opportunities to stop. But the machinery that I'm already using to log my trips knows my position anyway…

So I've plugged in a basic wireless network adaptor to the Pi's spare USB socket, and I combine this with my Huawei 585 wireless/3G bridge (a lovely device for net access on the move) to give the Pi a connection to the Internet. Every minute, it calls a script on one of my servers (via a VPN) and sends the current lump of JSON data from the GPS receiver (which contains location, speed, heading, etc.). That gets stored on the server.

The client side of this is another script which checks for a keyword supplied to authorised users (with an expiry time built in), then reads that most recent position, makes a call to OpenStreetmap Nominatim to get a human-readable description rather than just showing a lat-long pair, and puts up a simple page with the information plus an OpenStreetMap link (including a best guess at zoom level based on my speed).

So in return for a couple of hundred kilobytes of data transfer per hour, I can let people know how late I'm going to be without interrupting my driving.