Arduino DCF77 radio clock receiver – Hardware

(This is part 1 in a small series on using DCF77 for accurate time keeping with an Arduino. You can find post post #2 here and post #3 here)

This post deals with correctly connecting an Arduino to a DCF77 receiver, how to remove noise in the signal, in order to to decode the signal into a valid, atomic-clock-synchronized, time.

I use the “DCF-Empfänger BN 641138″ . It is relatively cheap and many others have reported good results. The connection is pretty simple, connect ground, and +5V to the Arduino and DCF output to a digital pin.

I connected the receiver to Arduino pin 2, because we can assign a flank-driven interrupt to it. It is important to connect the output to a pull-up resistor. Since I saw some spikes in the output signal (more on that later), I also added an additional bypass capacitor to decouple the power supply. Looking at the DCF board I see a capacitor that may already function as a bypass capacitor added, so feel free to leave this part out.

 

The schematic then looks like this:

Note: I used Fritzing to create the breadboard and schematic view. If you want to use this DCF77 component for Fritzing, I added it to the DCF77 library, which you can download here.

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