This is the decoder chip which is needed to decode the meteotime weather signal from DCF77. The price includes the required lifetime license from Meteotime. A detailed description of how the meteotime signal works can be found here. http://arduino-projects4u.com/home-weather-station/
The required software to operate this including the complete weather decoding algorithm can also be found on this page. (or use the link above)
You can also pre order an arduino shield which is a prototype PCB but has included the MSOP 8 IC footprint connected to the correct pins and also many alternatives to connect DCF77 decoding IC’s. I would recommend the Active antenna S DCFn which you can get from the HKW site. This needs the 3.5mm PCB Mountable 5 Pins Stereo Female Audio Jack Socket which you can also order from my site.
In addition this PCB will include a DCF77 transmitter which can communicate to any Meteotime weather station. So you can “program” the weather.
Decoder IC HKW581 overview (german)
Decoder IC HKW581 datasheet English (only with permission)
Arduino HKW581 shield (prototype PCB with add ons) schematic
Eagle files for Arduino HKW581 shield
DB W-Protokoll V1.7 2009-02-23 dt.pdf German (only with permission)
DB W-Protokoll V1.0 2006-10-27 dt.pdf German
DB W-Protokoll V1.7 2009-02-23 en.pdf English (only with permission)
Article: ei08_09_064.pdf German Wird morgen die Sonne scheinen?
Article: meteotime doc 25 9 06.pdf English about meteotime
Article: Meteotime Patent EP1798612A2.pdf Meteotime patent