BCD Binary Wrist Watch

A Wrist Watch version of my BCD Binary Clock!

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After the positive feedback about my Binary Clock project last year, I decided to make a wrist watch version.

It currently has 3 functions:
1 - Time mode: hh:mm:ss
2 - Date mode: dd:mm:yy
3 - Stopwatch mode: start, stop and reset

To interact with it, I decided to go with 3 capacitive touch buttons, instead of physical buttons. This gives it a much cleaner look I think.

By pressing the On/Off button the clock switches from active mode into sleep mode and vice versa. I purposefully didn't implement a timeout feature, because in my opinion that is just annoying. If I turn it on, I want to be able to look at it for as long as I want and when I'm done I'll turn it back off.

The Mode button simply switches between the 3 functions.

Depending on the mode, the Enter button allows you to set time/date, or in stopwatch mode, it will start/stop/reset the timer upon touch

The Watchstand shown in the second picture was made by PRIma on Thingiverse, link below!


As you can see, there is not a lot to it.

I'm using an ATTiny1617 because of its built in PTC (Peripheral Touch Controller). This makes using the capacitive touch buttons fairly easy since you can make use of the Atmel QTouch library. The RTC was mainly chosen because of its small size and built in oscillator.

Now to one of the most important parts of such a project, the battery life:

I've spent quite some time working on the software and making sure that current consumption is as low as possible in sleep mode. The hardest part was definitely getting the capacitive touch buttons / Atmel QTouch to work nicely in low power mode. In order for the capacitive touch buttons to work reliably, drifting has to be performed regularly. Which basicly means to perform an active measurement on the button regularly, to accommodate for changes in the environment and other things that could influence the reading of the button. The only problem was that this caused my average current consumption to go way higher, than what I was shooting for. 

So now after a lot of testing and tweaking, I was monitoring the current consumption over around 24h and got an average of 8.7µA.

With a typical capacity of a Varta CR2032 (230mAh) this should give it a battery life of:

230mAh/8.7µA = ~26436h or ~1100 days in sleep mode as a best case scenario.

The current consumption in active mode is around 3 - 3.5mA. So of course, like with everything else, it highly depends on how often and how long it's turned on. But I'm quite happy with it.


I designed the case in Fusion360 to fit a standard 18mm nato strap and then 3D printed it in regular PLA.

To mount the PCB I made some slots into the mounting posts, which can hold M1.4 nuts. Then the PCB can be screwed in by 4 black M1.4 screws.



Adobe Portable Document Format - 184.62 kB - 01/26/2019 at 14:05


  • Milled case:

    Tobias04/13/2019 at 08:18 0 comments

    I've been working on building a little desktop CNC over the last few weeks/months. Now that it's almost complete, I wanted to actually make something with it. I already tried milling a little test PCB with it, which worked fine:

    But I really wanted to try milling wood. So I tried milling the case for my Binary Watch. Considering this was my first attempt at milling a 3D shape, or pretty much milling in general, I'm really happy with the outcome:

    The black solder mask obviously fits the black 3D printed case much better, but nonetheless, this was a great first project to mill.
    Let me know what you think!

  • Quick Update and Showcase:

    Tobias03/10/2019 at 11:07 0 comments

    After not working on this for like a month, due to other things I've been doing. I finally managed to get the current consumption, which was giving me problems before, to where I'm happy with it. I've already updated the details section with further information about it.

    As requested I've also made a quick showcase of the watch:

View all 2 project logs

Enjoy this project?



rizkyesaramadhan9 wrote 02/10/2021 at 15:30 point

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wow, this is so amazing, i want to try to make it

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Joseph Hoven wrote 09/26/2020 at 03:59 point

Hey dude, that looks fantastic! I'd love to make one for myself if you would be willing to share your case design, code, and PCB files.

Thanks man!

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k1200s wrote 05/16/2019 at 19:31 point

Do you have the possibility to share the programming code and the gerbers of the PCB? This is a fantastic project that I'd like to make!

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normnet2 wrote 03/24/2019 at 12:18 point

Cool case design!

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neeek wrote 03/17/2019 at 15:09 point

This is amazing, I've been wanting one of these since I first saw one ! Nice work

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Tobias wrote 03/17/2019 at 15:37 point

Thanks, I'm glad you like it!

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Markkol96 wrote 02/03/2019 at 17:16 point

I just made an account just to follow this project. It's really interesting. Hope to one day get my self one of those. Keep up the good work

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Tobias wrote 02/04/2019 at 16:55 point

Thank you, I appreciate it!

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wklimecki wrote 01/30/2019 at 11:07 point

Great project ;) I would gladly buy one or two tiles. Can you show how mode selection works on yt? 

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Tobias wrote 02/04/2019 at 16:53 point

I'm still tweaking the software at the moment, minimizing current consumption and adding stuff. Once I'm done with that, I'll show more of it!

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Dan Maloney wrote 01/28/2019 at 16:34 point

Nice! I might have to steal that case design for a workout timer I'm working on with my daughter.

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Tobias wrote 01/28/2019 at 16:54 point

That sounds awesome, I'd love to see that when it's finished!

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Alexis wrote 01/27/2019 at 16:45 point

You should definitely put this wrist watch and the desk clock for sale. They are absolutely amazing.  You went really far with this one and its capacitive touch buttons. That is really really cool!

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Tobias wrote 01/28/2019 at 16:51 point

Right now I'm waiting for a 2nd batch of boards, because the silk screen around the buttons didn't come out that well, plus I want to clean up the software first. I might consider it though, since there are not a lot of components on this and they are not as pricey.

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Alexis wrote 01/30/2019 at 18:49 point

That's a great idea, can't wait to see them finished and ready to sell

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ActualDragon wrote 01/27/2019 at 02:45 point

Slick! Nice job, most of these watches and wearables are too big to casually wear. This isn't though, keep it up!

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Tobias wrote 01/27/2019 at 09:55 point

Thank you! One of the main goals was to keep the size as small as possible.

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