Wearable Hacks

829 Articles

Star Chart Watch Is A Romantic Tragedy

January 10, 2018 by 39 Comments

It’s becoming abundantly clear that [Colin Merkel] doesn’t know the definition of “good enough”. Not only has he recently completed his third (and most impressive) wristwatch build, but he also managed to put together one of the most ridiculously romantic gifts ever conceived. While some of us are giving our significant others a gift card to Starbucks, he made his girlfriend a watch with a chart on the face representing the position of the stars at the time and place of their first meeting.

As per his usual style, the documentation on this build is phenomenal. If paging through his gallery of build images doesn’t make you want to get a lathe and start learning metal working, nothing will. A chunk of stainless steel rod miraculously becomes a gorgeous wrist watch over the course of a few dozen images, perfectly encapsulating that old adage of “making it look easy”.

All you have to do is turn this into that. Easy.

Certainly the highlight of this build is the star chart on the face. To make it, he used PyEphem to plot the position of the brightest stars that were visible at the time and place of their first meeting. He then wrote a script to take those stars and convert their positions to G-Code the CNC could use to drill holes in the appropriate locations. The depth of the hole even corresponds to the magnitude (brightness) of each star, giving the chart a subtle 3D effect.

Unfortunately, [Colin] made a couple of mistakes during this build, to the point that he’s not exactly sure how to proceed. He mentions he might even be forced to start over from scratch. It’s hard to imagine how something that looks this good could ever end up being a failure, but the world of watch making is unkind.

To start with, he used 304 stainless instead of 303. This made machining the case much more difficult, and from his very first cut he realized it was going to be a problem. While it was an annoyance he mentions a couple times during the build log, he was at least was able to work through it.

The real problem came at the end, when he put the watch together. He originally made his designs assuming a front glass which was 0.5 mm thick, but in actuality used a piece that is 0.8 mm thick. This slight difference is just enough to cause the seconds hand to rub up on the glass, putting drag on the movement. The end result is that the battery dies extremely quickly, effectively rendering the watch useless.

We can’t imagine the heartbreak [Colin] felt when he realized what happened; we felt bad just reading about it. But given his track record, we have no doubt he’ll get the issue sorted out. It would be a shame to start over completely, but there’s some consolation in knowing it’s part of the learning process: you don’t become a master of your craft without making a couple mistakes along the way.

The predecessor to this watch was covered here at Hackaday last year, and made quite an impression. It’s interesting to see the improvements made between the two, and we’re certainly excited to see his next build.

3D Printing Wearables With A Net

January 6, 2018 by 4 Comments

If you want to build wearables, you need to know how to sew, right? Maybe not. While we’re sure it would come in handy, [Drato] (also known as [RobotMama]) shows how she prints designs directly on a net-like fabric. You can see a video of the process below.

The video after the break shows an Ultimaker, but there’s really nothing particularly special about the printer. The trick is to print a few layers, pause, and then insert the fabric under the printer before resuming the print.

[Drato] holds the fabric down after inserting it, and mentions you can use glue to hold it down, too. We wondered if some bulldog or alligator clips might work. The only thing we worried about is if the fabric were made of some synthetic, it might not take hot plastic without melting.

[Drato] mentions she uses Organza, which is a sheer fabric often found on wedding gowns. However, she doesn’t mention if she is using the polyester, silk, or nylon type of the fabric. A little research shows that polyester and nylon fabrics melt at about 295 C. Silk was harder to track down, but since you can iron it on a medium setting, that might work, too. Of course, the temperature where it melts and the temperature where it just deforms beyond use might be different, so some experimentation is probably wise.

What really piqued our interest was the application to creating wearables without sewing. We’ll be curious what other applications you could find for printing directly on a fabric substrate.

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34C3: Fitbit Sniffing And Firmware Hacking

December 29, 2017 by 19 Comments

If you walked into a gym and asked to sniff exercise equipment you would get some mighty strange looks. If you tell hackers you’ve sniffed a Fitbit, you might be asked to give a presentation. [Jiska] and [DanielAW] were not only able to sniff Bluetooth data from a run-of-the-mill Fitbit fitness tracker, they were also able to connect to the hardware with data lines using test points etched right on the board. Their Fitbit sniffing talk at 34C3 can be seen after the break. We appreciate their warning that opening a Fitbit will undoubtedly void your warranty since Fitbits don’t fare so well after the sealed case is cracked. It’s all in the name of science.

There’s some interesting background on how Fitbit generally work. For instance, the Fitbit pairs with your phone which needs to be validated with the cloud server. But once the cloud server sends back authentication credentials they will never change because they’re bound to to the device ID of the Fitbit. This process is vulnerable to replay attacks.

Data begin sent between the Fitbit and the phone can be encrypted, but there is a live mode that sends the data as plain text. The implementation seemed to be security by obscurity as a new Bluetooth handle is used for this mode. This technique prevents the need to send every encrypted packet to the server for decryption (which would be for every heartbeat packet). So far the fix for this has been the ability to disable live mode. If you have your own Fitbit to play with, sniffing live mode would be a fun place to start.

The hardware side of this hack begins by completely removing the PCB from the rubber case. The board is running an STM32 and the team wanted to get deep access by enabling GDB. Unfortunately, the debug pins were only enabled during reset and the stock firmware disables them at startup (as it should). The workaround was to rewrite the firmware so that the necessary GPIO remain active and there’s an interesting approach here. You may remember [Daniel Wegemer] from the Nexmon project that reverse engineered the Nexus 5 WiFi. He leveraged the binary patching he used on Nexmon to patch the Fitbit firmware to enable debugging support. Sneaky!

For more about 34C3 we have a cheatsheet of the first day and for more about Fitbit security, check out this WAV file.

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Environmentally Aware Jewelry Gets Attention

December 27, 2017 by 5 Comments

We didn’t include a “Most Ornate” category in this year’s Coin Cell Challenge, but if we had, the environmentally reactive jewelry created by [Maxim Krentovskiy] would certainly be the one to beat. Combining traditional jewelry materials with an Arduino-compatible microcontroller, RGB LEDs, and environmental sensors; the pieces are able to glow and change color based on environmental factors. Sort of like a “mood ring” for the microcontroller generation.

[Maxim] originally looked for a turn-key solution for his reactive jewelry project, but found that everything out there wasn’t quite what he was looking for. It was all either too big or too complicated. His list of requirements was relatively short and existing MCU boards were simply designed for more than what he needed.

On his 30 x 30 mm PCB [Maxim] has included the bare essentials to get an environmentally aware wearable up and running. Alongside the ATtiny85 MCU is a handful of RGB LEDs (with expansion capability to add more), as well as analog light and temperature sensors. With data from the sensors, the ATtiny85 can come up with different colors and blink frequencies for the LEDs, ranging from a randomized light show to a useful interpretation of the local environment.

It’s not much of a stretch to imagine practical applications for this technology. Consider a bracelet that starts flashing red when the wearer’s body temperature gets too high. Making assistive technology visually appealing is always a challenge, and there’s undoubtedly a market for pieces of jewelry that can communicate a person’s physical condition even when they themselves may be unable to.

Form or function, life saving or complete novelty, there’s still time to enter your own project in the 2017 Coin Cell Challenge.

A Watch Only A Ham Can Use

December 19, 2017 by 17 Comments

We’re not sure what to make of this one. With the variety of smartwatches and fitness trackers out there, we can’t be surprised by what sort of hardware ends up strapped to wrists these days. So a watch with an RPN calculator isn’t too much of a stretch. But adding a hex editor? And a disassembler? Oh, and while you’re at it, a transceiver for the 70cm ham band? Now that’s something you don’t see every day.

The mind boggles at not only the technical prowess needed to pull off what [Travis Goodspeed (KK4VCZ)] calls the GoodWatch, but at the thought process that led to all these features being packed into the case of a Casio calculator watch. But a lot of hacking is more about the “Why not?” than the “Why?”, and when you start looking at the feature set of the CC430F6137 microcontroller [Travis] chose, things start to make sense. The chip has a built-in RF subsystem, intended no doubt to enable wireless sensor designs. The GoodWatch20 puts the transceiver to work in the 430-MHz band, implementing a simple low-power (QRP) beacon. But the real story here is in the hacks [Travis] used to pull this off, like using flecks of Post-It notes to probe the LCD connections, and that he managed to stay within the confines of the original case.

There’s some real skill here, and it makes for an interesting read. And since the GoodWatch is powered by a coin cell, we think it’d be a great entry for our Coin Cell Challenge contest.

[via r/AmateurRadio]

Need A Hand? How About Two?

December 5, 2017 by 22 Comments

A helping hand goes a long way to accomplishing a task. Sometimes that comes in the form of a friend, and sometimes it’s a pair of robotic hands attached to your arm.

Italian startup [Youbionic] have developed this pair of 3D printed hands which aim to extend the user’s multi-tasking capacity. Strapped to the forearm and extending past the user’s natural hand, they are individually operated by flexing either the index or ring fingers. This motion is picked up by a pair of flex sensor strips — a sharp movement will close the fist, while a slower shift will close it halfway.

At present, the hands are limited in their use — they are fixed to the mounting plate and so are restricted to gripping tasks, but with a bit of practice could end up being quite handy. Check out the video of them in action after the break!

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