This is a WOSPi weather station.
A Davis Instruments Vantage Vue ISS (integrated sensor suite) outside sends readings wirelessly to a base console in my house. A Raspberry Pi (RPi) pulls the data from the console’s serial port and formats and uploads it to this site using the WOSPi code.
I chose a Davis for its build quality (weather stations do need to be largely weather proof) and the RPi because it’s small, cheap, silent, low power and hugely configurable.
My previous station was a Fine Offset WH3080 that connected to a netbook running Windows XP and the excellent Cumulus software. Indoors the netbook was large, power hungry and noisy but it all worked fine – until the outside stuff became unreliable and eventually died.
Replacing the XP netbook with a dedicated RPi falls in line nicely with my favourite Unix design ethos of “Do one thing. Do it well.” However, getting RPi to talk to the Davis console is a story in itself. It involves hardware hacking, programming of a microcontroller for a man in the middle attack, and a huge amount of frustration in order to pull what is essentially a few bits over a two wire interface that has been around since the 1960s.
Originally, access to the console serial interface was open and encouraged, with its commands well documented – making Davis an obvious instrument choice for many. However, Davis closed the serial interface in a console firmware update in 2012, making it only accessible with their own cable costing $160 US (irritatingly also £160 GBP). This is more than 50% extra on top of what the station costs in the first place – for a serial cable, some Windows based software that I cannot use and a RAM chip that I don’t need.
Thanks, Davis. My console. My data. Your customer.
Genuine thanks to Torkel M. Jodalen at annoyingdesigns.com for the information on getting this thing to fly – it’s all in the links above.