The IEEE Builds A Smart Watch

It used to be that building your own watch was either a big project or it meant that you didn’t really care about how something looked on your wrist. But now with modern parts and construction techniques, a good-looking smart watch isn’t out of reach of the home shop. But if you don’t want to totally do it yourself, you can turn to a kit and that’s what [Stephen Cass] did. Writing in IEEE Spectrum, he took a kit called a Watchy and put it through its paces for you.

Watchy is an open source product that uses an ESP32, an E-ink display, and costs about $50. The display is 1.5 inches — good enough for a watch — and it has a real time clock, a vibration motor, an accelerometer, and four buttons. The whole thing runs on a 200 mAh lithium polymer battery. The charger is microUSB and you can also upload software to it using the usual Arduino tools.

However, [Stephen] found that none of the examples he tried would work at first. He found problems with the Mac software, but he also had problems under Windows. The answer? Switching to a Raspberry Pi seemed to work and once the watch was wiped clean, the Mac tools would work, too. It sounds like this isn’t a common problem, but he has to erase the watch with the Pi before each programming cycle.

Unlike a normal Arduino program, all the work in a typical Watchy program happens in setup() so the watch can mostly sleep and it updates the 200×200 typically just once a minute. As an example, [Stephan] wrote a watch face that uses an old Irish alphabet to tell time. He plans to add code to grab online data, too, and the phone has support for connecting wirelessly and parsing JSON to make tasks like that easier.

We always thought the EZ430-Chronos was a good-looking watch, but its screen is dated now. You can also pick up a lot of cheap import watches that can be hacked.

24 thoughts on “The IEEE Builds A Smart Watch

    1. I’m on a new battery and a new screen on my pebble. I love it too much. I go to /r/pebble on reddit every now and then to see if a replacement has cropped up and nothing has. Plenty of other watches have come up, but they always fall down somewhere.

      Physical buttons, over a week battery life, shows me my notifications on my wrist. Why is that so difficult to do…

  1. One odd thing I noticed about Watchy is that it seems to have a good hardware real time clock (RTC) on the board, a Maxim/Dallas DS3231x (provided it is not the less stable DS3231M varient, or worse-yet a drifty Chinese clone). However it seems that out of the box there is no SNTP client library installed to set the time and date over the Internet.[1] Yes, Watchy would need to use the ESP32’s power-hungry WiFi to set the time, but only briefly (a few seconds if a fixed IP is used) and rather infrequently (once every few days perhaps, after all to prevent the Epaper display from wearing out, normally Watchy’s time display does not show rolling seconds). The good thing however is that Watchy is hackable, so an SNTP client can be added.


    1. Libraries Used

      1. Yeah, it looks nice, but I haven’t worn a watch that isn’t waterproof since I rusted one in college washing a pot in an industrial kitchen. I’ve been buying Casio watches good for 25 or 50 meters since then for about $20. I’d kill this one before it needed to be recharged.

    1. That’s a really good point! I appreciate the thought, as I was just about to hit purchase when I was reading over these comments. Considering I get about 180 days of rain a year around these parts, that could become a problem.

      Hardware isn’t really my wheelhouse, but would something like conformal coating work on an e-paper display?

  2. Nice kit. But it’s not something you want to wear while doing field work, watering the lawn, etc. I’ll with my Timex Espedition.

    To me this digital watch is more of work in progress than anything else.

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