rpi-weather

Python 2.7 application to get local weather forecast and display results via icons on LED 8x8 matrices.

Hardware

This program should work with any Raspberry Pi although I have only tested it with an original Model A (yes, an A). Also, any 4 Adafruit 8x8 LED Matrices with I2C Backpacks should work. Be sure to solder the address jumpers to set unique addresses for each. Expected range is 0x70-0x73.

Software

A brief description of the various software components.

• weather.py - gets and displays forecast
• rpi_weather.py - defines a class for interfacing with the hardware
• led8x8icons.py - contains a dictionary of icons
• clock.py - displays the time, for use as a clock

Dependencies

• Adafruit Python Library for LED Backpacks
  • https://github.com/adafruit/Adafruit_Python_LED_Backpack

Install

Simply clone this repo and run:

$ git clone https://github.com/caternuson/rpi-weather.git
$ cd rpi-weather
$ sudo python weather.py

Configure

The forecast location is specified with a zipcode. A default zipcode can be set in the code:

ZIPCODE = 98109

A zipcode can also be passed in from the command line, which will override the default:

$ sudo python weather.py 98109

Automation

The easiest way to have the program run on a daily basis is to use cron. Use crontab -e to add the following entry, which will run the program every morning at 4AM:

0 4 * * * sudo -E PYTHONPATH=$PYTHONPATH python /home/pi/rpi-weather/weather.py

NOTE: If you installed the program in a different location, change the path accordingly.

NOAA REST

The forecast is determined using the NOAA REST web service. Specifically, the Summarized Data for One or More Zipcodes. A typical request looks like:

http://graphical.weather.gov/xml/sample_products/browser_interface/ndfdBrowserClientByDay.php?zipCodeList=98109&format=12+hourly&numDays=4

The key bits being:

• zipCodeList - zipcode(s) for forecast
• format - choose either 12 or 24 hour period
• numDays - number of days in forecast

The request returns XML data. The icons are set by a simple text search in the weather-summary attribute of the weather-conditions tag.

Icons

Show this icon	If weather-summary contains
	SUNNY
	RAIN
	CLOUD
	SHOWERS
	STORM
	SNOW
	none of the above