Stylish OLED Watch Uses Accelerometer Instead Of Buttons

A few days ago [Andrew] contacted us to offer his help for the design of the mooltipass project case. While introducing himself, he casually mentioned his OLED watch that you can see above.

The watch is based on the low-power MSP430F microcontroller from Texas Instruments. It can consume as little as 1.5uA while maintaining a real-time clock and monitoring interrupts. It also uses ferroelectric RAM, which doesn’t need any power to retain its memory contents. That means there’s no need to set the time again if you remove the CR2016 battery that powers the watch.

[Andrew] chose an 0.96″ OLED display that only consumes up to 7mA. He also included an accelerometer that allows him to interact with the watch through its single and double tap detecting feature. He modeled his PCB using EagleCAD and the whole assembly using Sketchup. Most of the components were soldered in his reflow (toaster) oven. The final result is a mere 8.8mm thick and looks very professional in our opinion.

30 thoughts on “Stylish OLED Watch Uses Accelerometer Instead Of Buttons

  1. “That means there’s no need to set the time again if you remove the CR2016 battery that powers the watch.”

    I guess that depends on how long it takes you to replace the battery, and how much deviation from NST time you’re willing to tolerate. FRAM is good for non-volatile storage, like calibration settings and such. But RTCs require power.

  2. This! This! This is what I want on my wrist! Something programmable, practical, and not too big. Ideally with a little joystick or something to put Tetris or card games on. Did you know there’s no wrist-based games aimed at adults AT ALL!? Well probably you did, but I don’t like to wear my Tetris watch out too much, cos it’ll get damaged.

    If you need a project for next year, do a watch! A cheap, clever, versatile one. There’s currently nothing available that’s all three, even though there should be.

      1. You can already get those, though not cheap or user-programmable. Still yet to have one play Freecell though.

        Not too bothered about “accurate” as long as it’s close enough, I don’t need to time atoms. Standard digital watch accuracy is fine.

        1. For me, “accurate watch” is one I don’t have to reset the seconds/minutes except when I have to change the Hour setting for Daylight Savings On/Off. If it keeps within a half minute during that time frame, it is accurate enough for me.

    1. G-7710 is hardly a status symbol yet i had it on my wrist every day for the past couple years… mobile phones, especially smartphones are notoriously unreliable as a time source or alarm device, no to mention that they are many times bigger than a watch and much more inconvenient to wear on your body

      not saying that watch above is great but it certainly is easier to carry than any smartphone

        1. My watch is a mobile phone. Cheap Chinese wrist-phone. When you get used to it’s pretty bad interface, it’s pretty good. Plays MP3 and has a camera, which is overkill but that’s Chinese gadgetry for you, they like to add features. You can get “MP7” players now.

          But I’d prefer this one.

        1. Sure they are, thing is – my watch needs new battery every 2000 days, while i’m lucky when I get 2 days of my regular usage from my phone, and it is kind of useless to have precise clock in your pocket without way to check what it says when battery is dead. Not to mention that my watch isn’t going to break when dropped (which is unlikely anyway) and having a time on your wrist is far more convenient than pulling your phone from the pocket and putting it back…

  3. HAD commenters have become so lazy these days! If I’m going to wear a wristwatch for time, it’s going to be because I can “set it and forget it” — that means no worrying about a battery! So I quicky gathered some numbers.

    The low power MSP430 — 1.5 uA.
    The accelero in the low power mode i believe would support a “double tap” function — 6 uA.
    Powering the OLED for 1% of the day (~15 minutes) — 70uA equivalent (1% of 7mA).

    I can’t really read his schematics (low res jpg), so I’ve got to assume that chip on the mid-left is some sort of lower power charge pump. I’ve used them before, they’re monolithic apart from decoupling caps — pretty nifty. They are typically around 90% efficient.

    That gives us 86uA equivalent current draw (again, quick numbers). On a CR2016 cell (90mAh) that’s 1046 hours, or 43 days. Not too bad! However, these are some near-best-case numbers, don’t include everything (quiescent of OLED, full-on draw of the uC, internal losses of the coin cell, etc). I’d like to see him replace that cell with a rechargeable version, and add some sort of little recharge circuit… for mother earth!

    1. the text explains the ICs. there is a 2v under voltage protection IC and a 3v LDO. he says they’re to support LiPo cells. from what I can see there is a jumper link in the form of SMD pads that when shorted bypass this for use with a coin cell. so technically your rough numbers would be 53 days. over a week extra.

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