A person's hand wearing a black glove is shown in the right part of the image, making a series of gestures. A representation of a hand mimics those motions on a laptop screen.

Weaving Circuits From Electronic Threads

October 6, 2025 by Aaron Beckendorf 6 Comments

Though threading is a old concept in computer science, and fabric computing has been a term for about thirty years, the terminology has so far been more metaphorical than strictly descriptive. [Cedric Honnet]’s FiberCircuits project, on the other hand, takes a much more literal to weaving technology “into the fabric of everyday life,” to borrow the phrase from [Mark Weiser]’s vision of computing which inspired this project. [Cedric] realized that some microcontrollers are small enough to fit into fibers no thicker than a strand of yarn, and used them to design these open-source threads of electronics (open-access paper).

The physical design of the FiberCircuits was inspired by LED filaments: a flexible PCB wrapped in a protective silicone coating, optionally with a protective layer of braiding surrounding it. There are two kinds of fiber: the main fiber and display fibers. The main fiber (1.5 mm wide) holds an STM32 microcontroller, a magnetometer, an accelerometer, and a GPIO pin to interface with external sensors or other fibers. The display fibers are thinner at only one millimeter, and hold an array of addressable LEDs. In testing, the fibers could withstand six Newtons of force and be bent ten thousand times without damage; fibers protected by braiding even survived 40 cycles in a washing machine without any damage. [Cedrik] notes that finding a PCB manufacturer that will make the thin traces required for this circuit board is a bit difficult, but if you’d like to give it a try, the design files are on GitHub.

[Cedrik] also showed off a few interesting applications of the thread, including a cyclist’s beanie with automatic integrated turn signals, a woven fitness tracker, and a glove that senses the wearer’s hand position; we’re sure the community can find many more uses. The fibers could be embroidered onto clothing, or embedded into woven or knitted fabrics. On the programming side, [Cedrik] ported support for this specific STM32 core to the Arduino ecosystem, and it’s now maintained upstream by the STM32duino project, which should make integration (metaphorically) seamless.

One area for future improvement is in power, which is currently supplied by small lithium batteries; it would be interesting to see an integration of this with power over skin. This might be a bit more robust, but it isn’t first knitted piece of electronics we’ve seen. Of course, rather than making wearables more unobtrusive, you can go in the opposite direction. Continue reading “Weaving Circuits From Electronic Threads” →

Make DIY Conductive, Biodegradable String Right In Your Kitchen

March 28, 2025 by Donald Papp 3 Comments

[ombates] shares a step-by-step method for making a conductive bio-string from scratch, no fancy equipment required. She demonstrates using it to create a decorative top with touch-sensitive parts, controlling animations on an RGB LED pendant. To top it off, it’s even biodegradable!

The string is an alginate-based bioplastic that can be made at home and is shaped in a way that it can be woven or knitted. Alginate comes primarily from seaweed, and it gels in the presence of calcium ions. [ombates] relies on this to make a goopy mixture that, once extruded into a calcium chloride bath, forms a thin rubbery length that can be dried into the strings you see here. By adding carbon to the mixture, the resulting string is darkened in color and also conductive.

There’s no details on what the actual resistance of a segment of this string can be expected to measure, but while it might not be suitable to use as wiring it is certainly conductive enough to act as a touch sensor in a manner similar to the banana synthesizer. It would similarly be compatible with a Makey Makey (the original and incredibly popular hardware board for turning household objects into touch sensors.)

What you see here is [ombates]’ wearable demonstration, using the white (non-conductive) string interwoven with dark (conductive) portions connected to an Adafruit Circuit Playground board mounted as an LED pendant, with the conductive parts used as touch sensors.

Alginate is sometimes used to make dental molds and while alginate molds lose their dimensional accuracy as they dry out, for this string that’s not really a concern. If you give it a try, visit our tip line to let us know how it turned out!

Pick Up A Pebble Again

March 19, 2025 by Jenny List 38 Comments

A decade ago, smartwatches were an unexplored avenue full of exotic promise. There were bleeding-edge and eye-wateringly expensive platforms from the likes of Samsung or Apple, but for the more experimental among technophiles there was the Pebble. Based on a microcontroller and with a relatively low-resolution display, it was the subject of a successful crowdfunding campaign and became quite the thing to have. Now long gone, it has survived in open-source form, and now if you’re a Pebble die-hard you can even buy a new Pebble. We’re not sure about their choice of name though, we think calling something the “Core 2 Duo” might attract the attention of Intel’s lawyers.

The idea is broadly the same as the original, and remains compatible with software from back in the day. New are some extra sensors, longer battery life, and an nRF52840 BLE microcontroller running the show. It certainly captures the original well, however we’re left wondering whether a 2013 experience still cuts it in 2025 at that price. We suspect in that vein it would be the ideal compliment to your game controller when playing Grand Theft Auto V, another evergreen 2013 hit.

We look forward to seeing where this goes, and we reported on the OS becoming open source earlier this year. Perhaps someone might produce a piece of open source hardware to do the same job?

Hackaday Links: February 23, 2025

February 23, 2025 by Dan Maloney 7 Comments

Ho-hum — another week, another high-profile bricking. In a move anyone could see coming, Humane has announced that their pricey AI Pin widgets will cease to work in any meaningful way as of noon on February 28. The company made a splash when it launched its wearable assistant in April of 2024, and from an engineering point of view, it was pretty cool. Meant to be worn on one’s shirt, it had a little bit of a Star Trek: The Next Generation comm badge vibe as the primary UI was accessed through tapping the front of the thing. It also had a display that projected information onto your hand, plus the usual array of sensors and cameras which no doubt provided a rich stream of user data. Somehow, though, Humane wasn’t able to make the numbers work out, and as a result they’ll be shutting down their servers at the end of the month, with refunds offered only to users who bought their AI Pins in the last 90 days.

Continue reading “Hackaday Links: February 23, 2025” →

Custom Smartwatch Makes Diabetes Monitoring Easier For Kids

February 2, 2025 by Dan Maloney 21 Comments

Living with Type 1 diabetes is a numbers game. There’s not a moment in the day free from the burden of tracking your blood glucose concentration, making “What’s your number?” a constant question. Technology can make that question easier to ask and answer, but for T1D patients, especially the kids who the disease so often impacts, all that tech can be a distraction.

To solve that problem for his son, [Andrew Childs] built this custom T1D smartwatch. An Apple Watch, which integrates easily into the Dexcom CGM ecosystem, seems an obvious solution, but as [Andrew] points out, strapping something like that on a nine-year-old boy’s wrist is a recipe for disaster. After toying with some prototypes and working out the considerable difficulties of getting a stable BLE connection — the device needs to connect to his son’s iPhone to get CGM data — [Andrew] started work on the physical design.

The watch uses an ESP32-S3 on a custom PCB, as well as a 1.69″ TFT IPS display and a LiPo battery. The board also has an accelerometer for activity monitoring and a vibrator for haptic feedback. Getting all that into a case was no mean feat, especially since some degree of water resistance and shockproofing would be needed for the watch to survive. [Andrew] had a case made by a local 3D printing company, and he managed to source custom-cut and silkscreened glass for the face. The result is remarkably professional-looking, especially for a software developer who hadn’t really stretched his maker wings much before tackling this project.

[Andrew] doesn’t appear to have made build files available yet, although he does say he intends to open-source the project at some point. We look forward to that as it’ll be a big help to anyone trying to hack diabetes care. Until then, if you need a primer on continuous glucose monitoring, we’re happy to oblige.

ATTiny NFC Thermometer keychain with keys

Tiny NFC-Powered Keychain Thermometer

December 8, 2024 by Heidi Ulrich 9 Comments

What if your keychain could tell you the temperature, all while staying battery-free? That’s the essence of this innovative keychain ‘NFC_temp’ by [bjorn]. This nifty gadget harnesses energy from an NFC field—like the one created by your smartphone—to power itself just long enough to take a precise temperature reading. Using components like an ATTiny1626 microcontroller, a TMP117 thermometer, and an RF430CL330H NFC IC, NFC_temp cleverly stores harvested power in a capacitor to function autonomously.

The most impressive part? This palm-sized device (18×40 mm) uses a self-designed 13.56 MHz antenna to draw energy from NFC readers. The temperature is then displayed on the reader, with an impressive accuracy of ±0.1 °C. Creator [bjorn] even shared challenges, like switching from an analog sensor due to voltage instability, which ultimately led to his choice of the TMP117. Android phones work best with the tag, while iOS devices require a bit more angling for reliable detection.

Projects like NFC_temp underscore the creativity within open source. It’s a brilliant nod to the future of passive, wireless, energy-efficient designs. Since many of us will all be spending a lot of time around the Christmas tree this month, why not fit it in a bauble?

Hackaday Links: November 24, 2024

November 24, 2024 by Dan Maloney 6 Comments

We received belated word this week of the passage of Ward Christensen, who died unexpectedly back in October at the age of 78. If the name doesn’t ring a bell, that’s understandable, because the man behind the first computer BBS wasn’t much for the spotlight. Along with Randy Suess and in response to the Blizzard of ’78, which kept their Chicago computer club from meeting in person, Christensen created an electronic version of a community corkboard. Suess worked on the hardware while Christensen provided the software, leveraging his XMODEM file-sharing protocol. They dubbed their creation a “bulletin board system” and when the idea caught on, they happily shared their work so that other enthusiasts could build their own systems.

Continue reading “Hackaday Links: November 24, 2024” →