Turning on a lawn sprinkler only when there is no rain forecast!

This example was inspired by a comment on an article related to Home Automation using Raspberry Pi. The commenter mentioned:

The only home automation that I'm interested in (and still haven't seen) is something that'll turn off my lawn sprinklers if it's rained a certain amount in the preceding days or if it's raining on the day that the sprinklers are programmed to go on.

We decided to whip up a quick example that would turn on the sprinkler when it is not going to rain on a particular day.

Prepare for lift off

In order to check the weather forecast, we need to make the python-weather-api library (the library is distributed with MIT license). We will make use of the NOAA API. The library can be downloaded using the wget command:

wget https://launchpad.net/python-weather-api/trunk/0.3.8/+download/pywapi-0.3.8.tar.gz

The source files are available in a compressed folder. The contents of the compressed file can be extracted as follows...