In the past I got some complaints that my Blinkenlight Shield is not 100% Arduino compatible. Of course it is 100% compatible to the “real” Arduino. The issue is that the Arduino family never defined what they assume to be fully compatible. To learn about the nitty gritty details read the full story here. Of course you can avoid all these issues by using a Blinkenlighty in the first place.
Please keep in mind that both the Blinkenlighty and the Blinkenlight Shields are used to fund my site. Actually you can fund my site even without buying any of these products. You just need to follow this link to Amazon and buy whatever you want. Through the affiliate program I will then receive some money for further funding of my experiments.
My efforts with the DCF77 project are finished from a design point of view. However I am now converting it to a resuable library. I also work on the issue of making it available for the newer Arduino Uno models (which have a lousy oscillator). Next month I expect to have the first version ready. So stay tuned 🙂
Blinkenlight 
Keep up the great work!