Added README

Author: jonoxer

README

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+Weather Station Receiver
+========================
+
+Copyright 2009 Marc Alexander
+Copyright 2009 Jonathan Oxer
+
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+| This project is featured in the book "Practical Arduino" by         |
+| Jonathan Oxer and Hugh Blemings (Apress, 2009). More information    |
+| about the book and this project is available at:                    |
+|                                                                     |
+| www.practicalarduino.com/projects/medium/weather-station-receiver   |
++---------------------------------------------------------------------+
+
+The incredible popularity of home weather stations shows that it's not
+just farmers who are interested in the weather. Many people want to be
+able to track and record weather events within their local environment
+rather than relying on a state or national weather service that may not
+have adequate local details.
+
+Home weather stations typically consist of two major parts: the sensors
+that sit outside and measure temperature, wind speed and direction,
+humidity, rainfall, and barometric pressure; and the display unit that
+lives inside in a convenient place so you can read the external
+temperature while sitting around the fire warming your feet and
+deciding whether it's too cold to go fishing. Generally the external
+sensors connect together with cables with one sensor also acting as a
+transmitter to send updates wirelessly to the display unit.
+
+Many weather stations transmit their data at about 433MHz using a band
+reserved for low-power unlicensed use, which is ideal from a hacker's
+perspective because 433MHz receiver modules are commonly available for
+under $10 and can be easily interfaced with an Arduino to let you
+eavesdrop on the data feed. In fact it's not just weather stations that
+use this approach: many short-range wireless devices work on the same
+433Mhz band so the techniques used in this project can be just as easily
+applied to intercepting data from other devices such as domestic power
+usage monitoring systems. Best of all there's no modification required
+to the original device: it just transmits its data as usual, not even
+aware that it's being received and interpreted by another device. This
+project is essentially an exercise in listening to an unknown wireless
+data feed and converting the raw stream of data into values that make
+sense.
+
+Once you can receive the data and process it in your Arduino there are a
+wide range of things you can do with the information: you can simply
+display it as it updates, or you can log the readings and generate
+reports of trends over time, or you can even use it as the basis for
+making decisions such as feeding rainfall data to an irrigation system
+to minimise water usage.
+
+For this project we used a weather station from La Crosse, a popular
+brand that seems to be available in many parts of the world, but the
+same approach should work with other brands - as long as you can work
+out the data format! In fact many weather stations (including the La
+Crosse model we used) come with a serial interface on the display unit
+to feed data to a PC, but by doing the work directly in an Arduino with
+a receiver module you don't even need the display unit at all. And since
+many weather station sensors are available individually you may find you
+can buy just the sensors you want and save some money compared to buying
+a complete system, while also gaining the flexibility of managing the
+data through an Arduino.