Jailbroken Kindles make great weather displays come rain or shine
When Matt Petroff first came across e-ink displays, he instantly found a good use for the technology—a classy, almost real-time display for things like the weather, the date, or your agenda. With the new Kindle starting at $69, Matt began work on an e-paper weather forecast display.
As noted by Hack A Day, the main element of this hack is a server that fetches the weather forecast as well as other various bits of data. The server picks up the data and creates an image, while the Kindle displays that image. The Kindle, which needs to be jailbroken first, displays that day's weather along with a three-day outlook, with weather data from the National Digital Forecast Database. The data is pulled by cron just twice a day — enough to tell you if there are any drastic changes from morning to evening.
The server uses shell (a command-line interpreter script) and Python code to convert data for the Kindle. Before it reaches the Kindle, the data needs to be turned into an image. To do this, Matt puts the data into an SVG file that contains all the symbols and temperatures. Finally, the SVG file get converted into a grayscale PNG image, suitable for a Kindle display.
Whenever the data changes, the Kindle completely clears the screen to stop ghosting. Of course, to make sure an image is ready to appear on the screen, the server parses the fresh data five minutes before the Kindle actually needs it.
It's a pretty cool—and useful—trick, and you could add your own useful data to the image too, like a list of chores or meetings for the day, which refreshes at midnight.
If you want to give it a try with your Kindle, you can download Matt’s weather icons and source code from his blog.