My dad wanted to be able to remotely monitor rainfall, so this is what I
came up with. The adatper, pictured below, plugs into the parallel port
connector on the mother board, and has a few plugs available through a
slot on the back of the computer. A rain gauge, which closes a switch
each time a bucket tips (0.01" of rain falls), simply goes to a
parallel input. A temperature sensor transistor outputs controlled
voltage based on temperature, is run through and A-D converter and a
shifter, and into the parallel port. A status LED is hooked to an
output to indicate the operation of the station.
A small bit of python code records every time a bucket tips, and reads
temperature at regular intervals. This is recorded into daily files on
the harddrive. A set of scripts are used to plot temperature and rainfall
stored in these files. The linux OS is setup to answer incoming modem
calls and allow login, so the weather can be checked remotely.
Were i to do this again, I'd hookup a
'one-wire weather station'.