Sunrise Alarm Clock Uses DCF77 For Perfect Time


Here’s a sunrise alarm clock that keeps perfect time. It was designed and built by [Renaud Schleck] who also published a post detailing the process.

As you can see, a series of white LEDs inside of the transparent case which provide the simulated sunrise. As the days get short and the nights longer we do see the benefit of having your clock brighten the room before it jolts you out of your slumber. Speaking of, that alarm sound seems to be the weak link in his design. He’s using a square wave smoothed with capacitors to drive a speaker at either end of the case. We didn’t hear an example but we imagine this not the most gentle of sounds.

The rest of the design is quite well done. He’s using a 4×20 Character LCD display and adjusts the backlight using PWM. A DCF77 radio feeds data from an atomic clock signal to the MSP430 chip which runs the clock. There’s even a battery backup in case the power goes out.

We just saw a project yesterday that aims to improve signal quality with a DCF77 radio.

[via Reddit]

10 thoughts on “Sunrise Alarm Clock Uses DCF77 For Perfect Time

  1. As for the “weak” sound design: While choice is always good, and nothing is more flexible than loading your own mp3 into it, some of us are not awoken by softer sounds and nothing short of a harsh sound like this will do the trick.
    I’d imagine it would do some volume tricks to not start out harsh, to go with the theme of lighting the room to help you wake up, but for us non-morning-people this sounds like an awesome feature more than a weak area.

  2. Interesting. I’ve been looking at the one made by Philips. Their version has actually been approved as a medical device.

    My concern with the cheaper ones out there and the DIY solutions is if they can really give off the right kind of light and the right brightness and over the right period of time.

    Most of the other sunrise alarm clocks I’ve seen have pretty poor reviews. It seems that the device could actually make a major difference to someones life if everything is done correctly.

    1. Galane, you know, there is some stuff called “trees” and “hills” and “windows not facing to the east” and “sun which rises way too late in winter” which might sometimes prevent that from working. ;-)

    1. Actually they are certainly much weaker than your halogen projector. But they will still manage to wake you up before the alarm (I must admit that it does not work every morning). The clock has to be pretty close to your face ;-)

  3. I made myself a 200 led sunrise lamp before winter kicked in. I will never, ever go back to waking up in the dark. My girlfriend and I have both noticed it’s easier to get up and our mood first thing is much improved from previous winters. Would definitely recommend buying/making one. Mine’s based around an AtTiny85 and DS1307 (the time drifts a bit, but not enough that I care).

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