DIY Binary Alarm Clock Small Enough To Fit In Your Pocket


[linux-dude] always wanted to have a binary clock, but he didn’t want to pay someone else to make it for him. Additionally, he was looking for a compact alarm clock he could take on the road, rather than relying on the one in his hotel room.

Inspired by other binary clock projects he has seen over the years, he set off to build his own, which he wanted to fit inside an Altoids tin. His binary clock uses an Arduino Duemilanove (which fits perfectly in the tin) to keep time and control the indicator LEDs. The LEDs are arranged in two rows as you would expect, representing hours and minutes. A small piezo speaker serves as the alarm buzzer, which should be sufficient to wake up most people, though something bigger might be required for heavy sleepers.

We didn’t see any sort of battery pack or power plug mentioned, so we’re not quite sure how [linux-dude] keeps his clock juiced up. Additionally, the lack of an real time clock is something we’re puzzled by. While the Arduino does have a clock function that can be used, an RTC might serve him better – then again if he’s gone for just a day or two at a time, a small amount of drift may not be an issue.

22 thoughts on “DIY Binary Alarm Clock Small Enough To Fit In Your Pocket

    1. Beagle Board? Nice idea :) But it doesn’t fit in the ALTOIDS tin :( But I think there’s a pipe tobacco tin in some drawer which is big enough… Maybe I’ll use it next time

  1. “Additionally, he was looking for a compact alarm clock he could take on the road, rather than relying on the one in his hotel room.”

    Just accept the check-in desk’s offer of a wake-up call?

  2. I experimented with using an arduino as a RTC using interrupts and found that it’s quite accurate. If I recall, it would be very difficult to lose 60 seconds of accuracy in a month – so his solution is more than adequate if you ask me.

  3. I use my cell phone as an alarm clock most days and definitely on the road as I know how it functions as opposed to the last guest that set the alarm to AM talk radio at volume zero. Also, binary clocks are useless to anyone else that is staying with you. Hopefully, they will wake you up at 3 am to ask you to tell them what time it is lol. Pepper grinders “for that oh so fresh black pepper” (while all of your other herbs and spices are pre-ground) and binary clocks are two of the most useless inventions out there.
    Good for you to build something you want and can use. I am currently also in talks with a plastic manufacturer to make tiny plastic project boxes that are exactly the same size as an altoids tin ;)

    1. I’m pretty sure that the chemical companies that manufacture various forms of plastic wouldn’t have the machinery to mass produce your project boxes at any decent price. You might try talking with injection molding companies….

  4. don’t get me wrong, i have and use arduionos.
    but an arduino for an alarm clock isn’t much of a hack.

    go with bcd counters and some dip-switches. use 74266 to compare set time with current time and sets off an alarm when all bits are equal.
    rip a quartz oscillator from a cheap clock

    im pretty sure that’s smaller and cheaper than this.

  5. I like it. Seems like a nice little binary clock (and I can admit to having been bitten by the binary bug on occasion).

    Only thing I would have done differently: paint the face. It seems like it might be hard to read with the distracting Altoid’s logo in the background. A little paint goes a long way. I would do a custom paint job with acrylics, then a clear-coat enamel for protection, but even just flat black spray-paint would be easier on the eyes than this.

  6. I’ve never understood why people think binary clocks are so fantastic. Sure, they could be educational to throw together as a small learning project but actually making them to be used seems silly to me. They don’t offer any advantages to a “real” clock and they’re difficult to read. It’s not like you can take a quick glance and see what time it is, you actually have to look hard to see which LEDs are actually lit up. And in the dark, well then you have to feel around too to figure out which are on.

    If it’s just the “geek factor” I guess I can get behind that, but I’d love to hear some other solid reason.

      1. I’ve never understood people who don’t bother to read the entirety of posts.

        (Hint; I described why I personally don’t care for these types of watches and ended the post with asking people to share their reasons for the contrary. This was meant to indicate interest but I guess I wasn’t obvious enough.)

    1. I programmed a binary clock application for my phone and use it all the time. Binary clocks are difficult to read and require a bit of work but…why not do the work and learn to read them? It doesn’t cost me anything, it’s a nice mental exercise and (to me) it’s fun. When so much honest to God geekery is being co-opted by hipsters the real geeks have to retreat to something like binary clocks. The mark of a true geek!

  7. I love seeing a good Binary Clock project!

    I actually started my company, Wicked Device based on a Binary Clock Kit called Minty Time that I designed to fit into an Altoids tin.

    Minty Time is run by an ATTiny2313, uses a 3.6864MHz crystal and a timer to keep the time (quite accurately), uses PWM to conserve power, and uses an LDR to switch between dim and bright mode based on ambient light sensing. It has two buttons for independently setting the minutes and hours, and it also uses Binary Coded Decimal (BCD) encoding rather than “raw” binary. I had a lot of fun designing it and adding “features” and it’s been quite popular.

    At any rate, kudos to [linux-dude] for getting noticed by Hack-a-Day. Nice work!

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