ZSWatch: This OSHW Smart Watch Is As DIY As It Gets

January 16, 2023 by Tom Nardi 17 Comments

We say it often, but it’s worth repeating: this is the Golden Age of making and hacking. Between powerful free and open source software, low-cost PCB production, and high resolution 3D printers that can fit on your desk, a dedicated individual has everything they need to make their dream gadget a reality. If you ever needed a reminder of this fact, just take a look at the ZSWatch.

When creator [Jakob Krantz] says he built this MIT-licensed smart watch from scratch, he means it. He designed the 4-layer main board, measuring just 36 mm across, entirely in KiCad. He wrote every line of the firmware, and even designed the 3D printable case himself. This isn’t some wearable development kit he got off of AliExpress and modified — it’s all built from the ground up, and all made available to anyone who might want to spin up their own version.

The star of the show is the nRF52833 SoC, which is paired with a circular 1.28″ 240×240 IPS TFT display. The screen doesn’t support touch, so there’s three physical buttons on the watch for navigation. Onboard sensors include a LIS2DS12 MEMS accelerometer and a MAX30101EFD capable of measuring heartrate and blood oxygen levels, and there’s even a tiny vibration motor for haptic feedback. Everything’s powered by a 220 mAh Li-Po battery that [Jakob] says is good for about two days — afterwards you can drop the watch into its matching docking station to get charged back up.

As for the software side of things, the watch tethers to a Android application over Bluetooth for Internet access and provides the expected functions such as displaying the weather, showing notifications, and controlling music playback. Oh, and it can tell the time as well. The firmware was made with extensibility in mind, and [Jakob] has provided both a sample application and some basic documentation for would-be ZSWatch developers.

While an unquestionably impressive accomplishment in its current form, [Jakob] says he’s already started work on a second version of the watch. The new V2 hardware will implement an updated SoC, touch screen, and an improved charging/programming connector. He’s also looking to replace the 3D printed case for something CNC milled for a more professional look.

The ZSWatch actually reminds us quite a bit of the Open-SmartWatch project we covered back in 2021, in that the final result looks so polished that the average person would never even take it for being DIY. We can’t say that about all the smartwatches we’ve seen over the years, but there’s no question that the state-of-the-art is moving forward for this kind of thing in the hobbyist space.

Rollercoasters Are Triggering The IPhone’s Crash Detection System

October 12, 2022 by Lewin Day 68 Comments

Apple has been busy adding new features to its smartphone and smartwatch offerings. Its new iPhone 14 and Apple Watch 8 now feature a safety system that contacts emergency services in the event the user is in a automobile accident.

As with so many new technologies though, the feature has fallen afoul of the law of unintended consequences. Reports are that the “crash detection system” is falsely triggering on rollercoasters and in other strange circumstances. Let’s take a look at how these systems work, and why this might be happening.

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Because It’s Cool To Make A Watch That Thin

July 13, 2022 by Matthew Carlson 48 Comments

Recently [Richard Mille] and Ferrari (yes, that Ferrari) announced the thinnest mechanical watch ever made, the RM UP-01.

It measures a scant 1.75mm thick (~1/16 of an inch). The aesthetic is debatable, and the price tag is not even listed on the page, but we suspect it is a rather significant sum. But setting aside those two things, we’d like to step back and appreciate this as a piece of art. This is not a practical watch by any stretch of the imagination. This watch is the equivalent of a human-powered airplane. Impractical, costly, and not as effective as other modern mechanically-powered solutions. But that doesn’t make it any less impressive.

Since it is so thin, a regular stacked assortment of gears wasn’t an option. So instead, the gears were distributed over the watch’s surface, which led to a thin watch face. This means that winding is manual to save space, and a single winding will last around 45 hours. The heartbeat of any mechanical watch is the escapement. So they had to redesign the escapement to be flatter, doing away with the guard pin and the safety roller, instead using the anchor fork to bank the lever in case of unexpected forces or shocks.

The design is incredible but perhaps just as noteworthy is the fact that it could be machined. Machined out of titanium with a micron of accuracy, which is an incredible feat if you’ve seen a savage discussion of measurements. The smaller and more accurate you get, the steeper the difficulty curve.

A short teaser is available after the break.

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It’s TikTok, On Your Wrist!

June 1, 2022 by Jenny List 9 Comments

One of the ultimate objects of desire in the early 1980s was the Seiko TV wristwatch. It didn’t matter that it required a bulky external box in your pocket for its electronics, it was a TV on your wrist, and the future was here! Of course, now we have the technology to make wrist-mounted video a practical reality, but it’s sad to see we’ve opted to use our phones for video and never really followed up on the promise of a wrist-mounted television. There’s always hope though, and here it is in the form of [Dave Bennett]’s ESP32-powered TikTok wristwatch.

On the wrist is the ESP32 itself with an audio DAC and amplifier, LCD screen, and battery, but sadly this combo doesn’t have quite the power to talk to TikTok directly. Instead that’s done using Python on a companion PC with the resulting videos uploaded to the device over WiFi. It’s not the bulky electronics of the Seiko TV, so we’ll take it. All the info can be found on GitHub, and there’s a YouTube video below the break.

So the viral videos of a generation can now be taken on the move without resorting to a slightly less portable mobile phone. It may not be the most unobtrusive of timepieces, but it’ll certainly get you noticed.

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A Simple Binary Coded Decimal Watch

May 10, 2022 by Lewin Day 15 Comments

Analog and LCD watches are both useful designs, but ultimately are mainstream timepieces. Using a binary watch is an easy way to set one’s self apart as a tech enthusiast, while impressing your hacker friends to boot.

One such build comes to us from [vishalsoniindia], and it uses a single bare PCB which is designed to mate directly to a traditional watch strap. The single tactile button on board is used to activate the watch, showing the current time in hours and minutes in binary-coded decimal on the watch’s LEDs. Long-pressing the button puts the watch in setting mode to correct the time as needed.

The watch relies on an ATtiny85 microcontroller, a lightweight and compact design which is more than powerful enough to run a simple watch. It’s paired with a 74HC595 shift register to run all the LEDs from a minimum number of pins, and there’s also a TP4056 charging circuit on board to keep the lithium-polymer battery topped off.

A project like this is a great way to learn all manner of basic electronics skills, from PCB design, to SMD soldering and even working with basic logic parts like shift registers. As a bonus, you get a cool watch out of it to boot.

We’ve seen some similar designs over the years, as varied as the hackers that build them. Video after the break.

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Cool Mechanism Day: Two-Way To One-Way

March 14, 2022 by Dave Rowntree 8 Comments

The internal mechanisms that are used in timepieces have always been fascinating to watch, and are often works of art in their own right. You don’t have to live in the Watch Valley in Switzerland to appreciate this art form. The mechanism highlighted here (from Mechanistic on YouTube) is a two-way to one-way geared coupler (video, embedded below) which can be found at the drive spring winding end of a typical mechanical wristwatch. It is often attached to a heavily eccentrically mounted mass which drives the input gear in either direction, depending upon the motion of the wearer. Just a little regular movement is all that is needed to keep the spring nicely wound, so no forgetting to wind it in the morning hustle!

The idea is beautifully simple; A small sized input gear is driven by the mass, or winder, which drives a larger gear, the centre of which has a one-way clutch, which transmits the torque onwards to the output gear. The input side of the clutch also drives an identical unit, which picks up rotations in the opposite direct, and also drives the same larger output gear. So simple, and watching this super-sized device in operation really gives you an appreciation of how elegant such mechanisms are. Could it be useful in other applications? How about converting wind power to mechanically pump water in remote locations? Let us know your thoughts in the comments down below!

If you want to play with this yourselves, the source is downloadable from cults3d. Do check out some of the author’s other work!

We do like these super-sized mechanism demonstrators around here, like this 3D printed tourbillon, and here’s a little thing about the escapement mechanism that enables all this timekeeping with any accuracy.

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This ESP32 Pico Wristwatch Has Plenty Of Potential

February 12, 2022 by Dave Rowntree 12 Comments

First hand-built prototype. Nurse! isopropyl alcohol, stat!

Prolific hacker [Sulfuroid] is a medical doctor by day, and an electronics hobbyist by night, and quite how he finds the time, we have no idea.

The project we want to highlight is an ESP32 based LED smart watch, which we’ll sure you’ll agree, looks pretty nicely developed so far, and [Sulfuroid] has bigger plans, as you may find, when you dig into the GitHub repo. This analog-style design uses four groups of 0603-sized LEDs, arranged circularly to indicate the passage of time, or anything else you fancy. Since there are four control buttons, a pancake vibration motor, as well as Wi-Fi and Bluetooth, the possibilities are endless.

In order to stand a hope of driving those 192 LEDs from a single ESP32-Pico-D4, it was necessary to use a multiplexed LED driver, courtesy of the Lumissil IS31FL3733 device, which can handle arrays up to 12 x 16 devices. This chip is one to remember, since it has some really nice features, such as global current control to reduce CPU overhead, automatic breathing loops for those fancy fade effects, and even includes a handy open/short detection function, so it can report back assembly problems, assisting in reworking your dodgy soldering!

Power and interfacing are taken care of via USB-C, with a TP4054 single Li-Ion cell charger chip handling the battery. This is a Taiwanese clone of the popular LTC4054, but that chip may be a bit hard to get at the moment. There is the common-as-muck CP2104 USB chip dealing with the emulated serial port side of things, since for some reason, the ESP32 still does not support USB. The Pico-D4 does have RTC support, but [Sulfuroid] decided to use a DS3231M RTC chip instead. We noticed the touch functionality wasn’t broken out – that could be added easily in the next revision!

We’ve covered watches a lot, because who doesn’t want custom geek-wear! Here’s a slick one, a fun one with the brains on display, and finally one using charlieplexing to get the component count down.