Open Source Binary Wristwatch Is Professional Quality

If you want to proclaim to the world that you’re a geek, one good way to go about it is to wear a wristwatch that displays the time in binary. [Jordan] designs embedded systems, and he figured that by building this watch he could not only build up his geek cred but also learn a thing or two about working with PIC microcontrollers for low power applications. It seems he was able to accomplish both of these goals.

The wristwatch runs off of a PIC18F24J11 microcontroller. This chip seemed ideal because it included a built in real-time clock and calendar source. It also included enough pins to drive the LEDs without the need of a shift register. The icing on the cake was a deep sleep mode that would decrease the overall power consumption.

The watch contains three sets of LEDs to display the information. Two green LEDs get toggled back and forth to indicate to the user whether the time or date is being displayed. When the time is being displayed, the green LED toggles on or off each second. The top row of red LEDs displays either the current hour or month. The bottom row of blue LEDs displays the minutes or the day of the month. The PCB silk screen has labels that help the user identify what each LED is for.

The unit is controlled via two push buttons. The three primary modes are time, date, and seconds. “Seconds” mode changes the bottom row of LEDs so they update to show how many seconds have passed in the current minute. [Jordan] went so far as to include a sort of animation in between modes. Whenever the mode is changed, the LED values shift in from the left. Small things like that really take this project a step further than most.

The board includes a header to make it easy to reprogram the PIC. [Jordan] seized an opportunity to make extra use out of this header. By placing the header at the top of the board, and an extra header at the bottom, he was able to use a ribbon cable as the watch band. The cable is not used in normal operation, but it adds that extra bit of geekiness to an already geeky project.

[Jordan] got such a big response from the Internet community about this project that he started selling them online. The only problem is he sold out immediately. Luckily for us, he released all of the source code and schematics on GitHub so we can make our own.

28 thoughts on “Open Source Binary Wristwatch Is Professional Quality

  1. nice job. good selection of parts vs needs, rather than just picking a popular chip platform. size looks idea. does not look bulky at all. well done.

    re: colored ribbon cable, lol! I love that stuff and buy it up whenever I can find it. at surplus stores, there is always red stripe ribbon but almost never multicolor. it really makes DIY a lot easier, I use it for runs between boards using molex inline connectors and headers. if your connectors are not keyed (most diy is not) then having colors really helps.

    1. Glad you like it! The choice in cable was actually just a result of me having a giant spool of it that I liberated from a dumpster years ago. I agree though, it makes things so much easier when you can just label signals by color as opposed to having to count out to the seventh wire on the ribbon!

  2. Yes, because for years watch makers have been trying to be the best in watches that have the absolute minimum in weather protection. While a real Rolex nowadays can’t barely function when it’s a bit damp, this watch will certainly have trouble in a drizzle.
    Forget those bodgers with their “100 feet” underwater survivability… Amateurs!

      1. I think ‘professional quality’ is rather subjective term in this case, The PCB and circuit are very well thought out and executed from a ‘professional’ standpoint. But at the same time as a final product you just don’t ship bare PCBs as a mechanically ‘professional’ design to end-users. Further blurring these distinctions though is that the end-users want it to be visible for some ‘nerd cred.’

        It fills it’s need and it fills it well, but a typical end-user product it is not.

    1. If you’re local, you should check out the Austin Hackerspace. I just recently got a membership there (great way to get access to CNC milling/routing tools), and the community is pretty great. Still trying to convince someone there that it’d be worth it to get a reflow oven :)

      1. I’ll have to check them out, thanks

        Not even a reflow toaster? The only thing keeping me from making my own is a lack of a ventilated workspace and the odd absence of old toaster ovens at local Goodwills. Maybe I have a new project to help with there…

        1. Any Austin locals should come by Long Center on Friday (3/13/15) at 11am for the Hackaday SXSW meetup. We’ll also have a booth at SXSW Create all weekend. Both are free to attend and it would be great to meet you!

  3. I would suggest a plastic (acrylic, since its easy and cheap and laser-able) casing for it. a flat bottom piece, a middle ‘spacer’ piece and a top piece would really go a long way in sealing it and stiffening it.

    3d printed would be nice, too, but even just ‘simple’ laser cut top/middle/bottom pieces would be an improvement.

    1. I considered that as well, but my original intent with these was to make 10-15 to give to friends as gifts. I was comfortable with doing the schematic design, part selection, board layout, soldering, and programming, but adding custom enclosures on top of that would have made for an unrealistic work load (for me, anyway : )

      I’m not sure what you mean by “stiffening it” though; the watch in its current state is actually surprisingly comfortable, and as long as the ribbon cable is the right length, its flexibility hasn’t caused me any issues.

      I definitely agree that sealing it would be a good thing though, for ESD reasons more than anything else. I’m currently looking into either acrylic spray or epoxy dipping for future projects.

      1. Fry’s sells a transparent silicone conformal coating spray (MG Chemicals I think) that might also work. Bonus is it has a UV fluorescent dye for inspection, so it glows under black light.

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