An Arduino Watch Without A Clock

When you show up at a party wearing this bare PCB watch, there are effectively two possible reactions you might receive from the other people there. Either they are going to snicker at the nerd who’s wearing a blinking circuit board on their wrist in public, or they are going to marvel at the ridiculously low part count. We’ll give you one guess as to which reaction you’d likely get at any event Hackaday is involved in.

Designed and built by [Electronoobs], this extremely simple watch consists of a ATmega328P microcontroller, a dozen LEDs with their associated 200 Ω resistors, and a battery. There’s also a single push button on the front which is used to not only set the watch, but turn the LEDs on when you want to check the time. Short of dropping down to one LED and blinking out the time, it’s hard to imagine a timepiece with fewer components than this.

You’re probably wondering how [Electronoobs] pulled this off without an external clock source for the ATmega328P chip. The chip actually has an internal 8 MHz oscillator that can be used, but you need to flash the appropriate bootloader to it first. Accordingly, the backside of the PCB has both SPI and a UART solder pads for external bootloader and firmware programming.

As you might expect, there’s a downside to using the internal oscillator: it’s not very good. The ATmega328P spec sheet claims a factory calibrated accuracy of ±10%, and [Electronoobs] has found that equates to a clock drift of around 15 seconds per day. Not exactly great, but considering the battery only lasts for two days anyway, it doesn’t have much of an impact in this case.

Compared to other “analog” LED watches we’ve seen, the simplicity of this build is really quite remarkable. The closest competitor we’ve seen so far is this slick binary watch.

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A Surprisingly Practical Numitron Watch

Regular Hackaday readers are surely familiar with Nixie tubes: the fantastically retro cold cathode display devices that hackers have worked into all manner of devices (especially timepieces) to give them an infusion of glowing faux nostalgia. But unfortunately, Nixie displays are fairly fragile and can be tricky to drive due to their high voltage requirements. For those who might want to work with something more forgiving, a possible alternative is the Numitron that uses incandescent filaments for each segment.

There hasn’t been a lot of prior-art that utilizes Numitrons, but that might be changing, given how fantastic this wristwatch created by [Dycus] looks. With a multi-day battery life, daylight readability, and relatively straightforward construction, the Filawatch is likely to end up being something of a reference design for future Numitron watches.

[Dycus] has gone through three revisions of the Filawatch so far, with probably at least one more on the way. The current version is powered by a ATmega328 microcontroller with dual 16-bit LED drivers to control the filaments in the KW-104S Numitron display modules. He’s also included an accelerometer to determine when the wearer is looking at the display, and even a light sensor to control the brightness of the display depending on the ambient light level.

If there’s a downside to Numitron displays, it’s their monstrous energy consumption. Just like in the incandescent light bulbs most of us have been ditching for LED, it takes a lot of juice to get that filament glowing. [Dycus] reports the display draws as much as 350 mA while on, but by lighting it up for only five seconds at a time it can be checked around 150 times before the watch needs to be recharged.

Its been a few years since we’ve seen a Numitron watch, and it’s interesting to see how the state of the art has advanced.

[via /r/electronics]

A BCD Wristwatch You’d Want To Wear

Timepieces are a staple of Hackaday, we have featured so many of them over the years that for us to become really excited by a fresh one it must be particularly special. The days when simply breaking out the Nixies was enough are long past.

So this binary wristwatch project by [Sverd Industries] definitely caught our eye. Not for being particularly novel, after all binary LED clocks are not in themselves hard, but for the exceptionally high quality of its construction. It’s a simple enough design, with a real-time clock chip and an ATmega328 in its most power-sipping mode on a circular PCB with an array of LEDs as the display, and all contained within a 3D-printed shell.

This design has real quality, the discrete components are tucked underneath the board leaving the  ICs on the top with only the LEDs for company. The glass front is glued into place, and the shell is professionally 3D-printed. Power comes from a single CR2032, and to save battery life the LEDs are only activated by the press of a concealed button. We would wear this watch. For that matter, you would wear this watch. Take a look at the video below the break, and we’re sure you’ll agree. Looks like a few are even available over on Tindie.

This isn’t the first binary watch we’ve featured, so it’s tough to pick a comparison. This very low BoM example might lack some of the polish of the one presented here, but it has the same ability to catch our eye.

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LEDs Make An “Analog” Wristwatch

If you just came down in the last shower, you’re probably used to living in a world where LEDs are cheap, awesome, and practically everywhere. Spare a thought for those of us who lived before the invention of high brightness LEDs – these things still amaze us! A great example of how far we’ve come is this “analog” watch build by [Kevin], featuring no less than 73 of the critters.

The microcontroller running the watch is an STM32, chosen for its easy programmability. It’s running the LEDs in an emulation of the dial of an analog clock, hence the high part count. Naturally, it’s no simple task to cram 73 LEDs and all the necessary connections into the confines of a watch-sized PCB. [Kevin] goes into great detail about the challenges involved, from routing the traces to a tricky power draw problem caused by some odd blue LEDs.

Watch builds are always fun, and they make great conversation pieces for when you want to amaze strangers with your tales of battles fought in the PCB design suite. Now check out this similar build with an entirely different style. 

 

Dive Inside This Old Quartz Watch

In an age of smartwatches, an analog watch might seem a little old-fashioned. Whether it’s powered by springs or a battery, though, the machinery that spins those little hands is pretty fascinating. Trouble is, taking one apart usually doesn’t reveal too much about their tiny workings, unless you get up close and personal like with this microscopic tour of an analog watch.

This one might seem like a bit of a departure from [electronupdate]’s usual explorations of the dies within various chips, but fear not, for this watch has an electronic movement. The gross anatomy is simple: a battery, a coil for a tiny stepper motor, and the gears needed to rotate the hands. But the driver chip is where the action is. With some beautiful die shots, [electronupdate] walks us through the various areas of the chip – the oscillator, the 15-stage divider cascade that changes the 32.768 kHz signal to a 1 Hz pulse, and a remarkably tiny H-bridge for running the stepper. We found that last section particularly lovely, and always enjoy seeing the structures traced out. There are even some great tips about using GIMP for image processing. Check out the video after the break.

[electronupdate] knows his way around a die, and he’s a great silicon tour guide, whether it’s the guts of an SMT inductor or a Neopixel close-up. He’s also looking to improve his teardowns with a lapping machine, but there are a few problems with that one so far.

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Hawkeye, the 3D-Printed Tourbillon Movement

As if building tiny mechanisms with dozens of moving parts that all need to mesh together perfectly to work weren’t enough, some clock and watchmakers like to put their horology on hard mode with tourbillon movements. Tourbillons add multiple axes to the typical gear trains in an attempt to eliminate errors caused by the influence of gravity — the movement essentially spins on gimbals while tick-tocking away.

It feels like tourbillons are too cool to lock inside timepieces meant for the ultra-rich. [Alduinien] agrees and democratized the mechanism with this 3D-printed tourbillon. Dubbed “Hawkeye,” [Alduinien]’s tourbillon is a masterpiece of 3D printing. Composed of over 70 pieces, the mechanism is mesmerizing to watch, almost like a three-axis mechanical gyroscope.

The tourbillon is designed to be powered either by the 3D-printed click spring or by a small electric motor. Intended mainly as a demonstration piece, [Alduinien]’s Thingiverse page still only has the files for the assembled mechanism, but he promises to get the files for the individual pieces posted soon. Amateur horologists, warm up your 3D-printers.

Tourbillons are no stranger to these pages, of course. We’ve done an in-depth look at tourbillons for watches, and we’ve even featured a 3D-printed tourbillon clock before. What we like about this one is that it encourages exploration of these remarkable instruments, and we’re looking forward to seeing what people do with this design. For those looking for more background on clock escapements in general, [Manuel] wrote a great article on how we turned repetitive motion into timekeeping.

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“Attempt” at Wristwatch is a Solid Success

Sometimes silence is the best compliment to a DIY project, and that doesn’t just apply to homemade lockjaw toffee. When a watch is so well-made that it looks like one from a jewelry store, it is easy to keep quiet. [ColinMerkel] took many pictures of his fourth wristwatch attempt but “attempt” is his word because we call this a success. This time around he didn’t forget the crown for adjusting the time so all the pieces were in place.

His second “attempt” at wristwatch making was featured here and it had a classical elegance. Here, the proverbial game has been stepped up. Instead of using stock steel, the body is constructed of 303 stainless steel. The watch dial will definitely draw compliments if its DIY nature is revealed, which is equally mathematical and charming. Pictures of this process were enough to convey the build without words which is always a bonus if you only want a quick look or English isn’t your first choice for language.

Not only is [Colin] an upstanding horologist, he has a reputation with aftermarket door security and a looping guitar pedal.