I have always been interested in the weather, part I guess as it
plays a big part in propagation (Ham Radio) and also
as I don't like riding motor-bikes in the rain etc.

Getting back in to Ham radio I chanced upon aprs, which has sort of
taken over from the Packet radio (ax25), I was so involved with in
back in the early 90's. With aprs I discovered an active army of
weather enthusiasts connecting either via aprs or the cwop, citizens
weather program.

I had a Raspberry Pi zero-w knocking about so I bought a BME280
sensor and connected it up to the Pi. To read the atmospheric
pressure I installed the Ada-Fruit Python library
for the GPIO and BME280, then hacked one of the scripts so I could
dump out the data in to a text file to manipulate using a 'bash'
script I knocked up. 

Using a 'bash' script (see the scripts directory/aprs_bash_script), I
was able to run a cron job and send pressure data on to the aprs
network :)