A sunrise clock for those cold, dark winter mornings


For most of the working world, the onset of autumn and winter in the Northern hemisphere means one thing – waking up well before the sun rises to get a start on the daily grind. [Brent] from Freeside Atlanta knows that routine well and decided to build himself a sunrise alarm clock in an attempt to wake himself more naturally on those dark mornings.

He bought an assortment of LEDs in varying colors including blue, red, yellow, and white, along with a few UV diodes for good measure. His goal with this array of LEDs was to simulate the natural colors of the sunrise, rather than simply slowly brightening the room. The clock uses a DS1307 RTC to keep the time, and an Arduino is tasked with lighting the LEDs about 25 minutes before it’s time for [Brent] to wake up.

He says that it seems to be working pretty well, gently waking his body before the clock radio kicks in. It certainly beats a loud buzzer!


  1. 5s5 says:

    This looks like an awesome project. great job!

  2. nate says:

    Nice! I’ve been thinking about building one of these myself. I was just going to use some white LEDs I have left over from a previous project, but I really like the idea of using natural colors. I wonder how effective those UV LEDs are in this project.

  3. Bogdan says:

    I’m just curious if the LEDs make enough light to be comparable even with an artificially lit room, not to mention a bright sunny morning….which is what i would target…

    • BrentC says:

      Not using diffused LEDs and using the glass to diffuse this makes it semi-directional. Point it at the bed and you get enough light to make it no fun to sleep through. It’s not as bright as flipping on all the lights in the room, but it’s enough to get you to notice.

    • BrentC says:

      Oh, and if space isn’t a concern, you could add another 3 banks of LEDs to get a massive amount of light without having to change the maxBrightness in the ShiftPWM setup. All you’d have to do is chain them off the end of the shift register set up and add them to the code for the wake up sequence.

  4. Stevie says:

    No video?

  5. Bhima says:

    I have a similar device. It’s little things like this that make your life more enjoyable.

  6. Martin says:

    I miss the sound of my alarm clock and the concept of only waking at dawn. An HA-Pair of babies renders such luxuries a distant memory. Anyone got any suggested hacks for babies?

  7. meatman says:

    Lot easier to simply use 2 triacs and PWM a pair of 40 wall light bulbs.

    Plus you will generate a lot more light in the room to wake you up instead of a single panel that must be mounted to fire at the face of the person.

    color means nothing other than for looks, gradual light level change is what is more important. use “daylight” color coated bulbs to give you the bluish color that your body is really after.

  8. Joey Y says:

    I know my version does not count as a real hack, since it is all off the shelf parts, but I have a 7-day AC timer with a lamp plugged into it. It does not fade in or anything. It is great, even if just west-facing rooms.

    Oh, and the folks in the southern hemisphere has the same problem in fall and winter.

  9. aarku says:

    A few LEDs aren’t going to wake me up. I use a 1k watt halogen work lamp and control it via software and the proprietary INSTEON home automation stuff. It’s only about a meter from my head, so it’s something around 20k lux on my eyelids I’d wager. Feels good man. Just need three more lights so I can wake up screaming “There are four lights!” just like Picard.

  10. Owen says:

    I was expecting him to be using this sunrise/sunset arduino library. It calculates the actual sunrise time based on your location and seems to work pretty well.

  11. PKM says:

    For a simpler approach, you can use a timeswitch to turn on the Arduino at the appropriate time, and one of those cheap camping lights provides a source of white LEDs- http://www.instructables.com/id/Simple-Arduino-Sunrise-Lamp/

    I hadn’t thought about the effect of different colours, though.

    • BrentC says:

      Not sure if the colors actually do anything, but it does make it a more gradual, less shocking wake up. I’m usually stirring and noticing that the clock is on at around the red/yellow shift. When it’s full white I’m awake fully. I like the idea of the time switch to just power on the Arduino.

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