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1349 Articles

Make DIY Conductive, Biodegradable String Right In Your Kitchen

March 28, 2025 by 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!

LED Filaments Become Attractive Time Piece

March 25, 2025 by 39 Comments

There are a million ways to use LEDs to make a clock. [sjm4306] chose to go a relatively conventional route, making something that approximates a traditional analog timepiece. However, he did it using LED filaments to create a striking and unique design. Thus the name—FilamenTIME!

LED filaments are still relatively new on the scene. They’re basically a bunch of tiny LEDs mounted in a single package to create a single “filament” of light that appears continuous. It’s great if you want to create a bar of light without messing around with populating tons of parts and having to figure out diffusion on your own.

[sjm4306] used them to create glowing bar elements in a clock for telling the time. The outer ring contains 60 filaments for the 60 minutes in an hour, while the inner ring contains 12 filaments to denote the hours themselves. To handle so many LEDs, there are 9 shift registers on board. They’re driven by an ATmega328P which runs the show, with a DS3232MZ real-time clock onboard for keeping time.  As you might imagine, creating such a large circular clock required a large PCB—roughly a square foot in size. It doesn’t come cheap, though [sjm4306] was lucky enough to have sponsorship to cover the build. [sjm4306] is still working on the firmware, and hopes to build a smaller, more compact version, which should cut costs compared to the large single board.

It’s a neat clock, and we’d know, having seen many a timepiece around these parts. Video after the break.

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A Modern Take On The Etch A Sketch

March 20, 2025 by 6 Comments

The Etch A Sketch is a classic children’s toy resembling a picture frame where artwork can be made by turning two knobs attached to a stylus inside the frame. The stylus scrapes off an aluminum powder, creating the image which can then be erased by turning the frame upside down and shaking it, adding the powder back to the display. It’s completely offline and requires no batteries, but in our modern world those two things seem to be more requirements than when the Etch A Sketch was first produced in the 1960s. Enter the Tilt-A-Sketch, a modern version of the classic toy.

Rather than use aluminum powder for the display, the Tilt A Sketch replaces it with an LED matrix and removes the stylus completely. There are no knobs on this device to control the path of the LED either; a inertial measurement unit is able to sense the direction that the toy is tilted while a microcontroller uses that input to light up a series of LEDs corresponding to the direction of tilt. There are a few buttons on the side of the device as well which allow the colors displayed by the LEDs to change, and similar to the original toy the display can be reset by shaking.

The Tilt-A-Sketch was built by [devitoal] as part of an art display which allows the visitors to create their own art. Housed in a laser-cut wooden enclosure the toy does a faithful job of recreating the original. Perhaps unsurprisingly, the Etch A Sketch is a popular platform for various projects that we’ve seen before including original toys modified with robotics to create the artwork and electronic recreations that use LED displays instead in a way similar to this project.

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World’s Smallest Blinky, Now Even Smaller

March 19, 2025 by 29 Comments

Here at Hackaday, it’s a pretty safe bet that putting “World’s smallest” in the title of an article will instantly attract comments claiming that someone else built a far smaller version of the same thing. But that’s OK, because if there’s something smaller than this nearly microscopic LED blinky build, we definitely want to know about it.

The reason behind [Mike Roller]’s build is simple: he wanted to build something smaller than the previous smallest blinky. The 3.2-mm x 2.5-mm footprint of that effort is a tough act to follow, but technology has advanced somewhat in the last seven years, and [Mike] took advantage of that by basing his design on an ATtiny20 microcontroller in a WLCSP package and an 0201 LED, along with a current-limiting resistor and a decoupling capacitor. Powering the project is a 220-μF tantalum capacitor, which at a relatively whopping 3.2 mm x 1.6 mm determines the size of the PCB, which [Mike] insisted on using.

Assembling the project was challenging, to say the least. [Mike] originally tried a laboratory hot plate to reflow the board, but when the magnetic stirrer played havoc with the parts, he switched to a hot-air rework station with a very low airflow. Programming the microcontroller almost seemed like it was more of a challenge; when the pogo pins he was planning to use proved too large for the job he tacked leads made from 38-gauge magnet wire to the board with the aid of a micro hot air tool.

After building version one, [Mike] realized that even smaller components were available, so there’s now a 2.4 mm x 1.5 mm version using an 01005 LED. We suspect there’ll be a version 3.0 soon, though — he mentions that the new TI ultra-small microcontrollers weren’t available yet when he pulled this off, and no doubt he’ll want to take a stab at this again.

DIY Your Own Red Light Therapy Gear

March 18, 2025 by 104 Comments

There are all kinds of expensive beauty treatments on the market — various creams, zappy lasers, and fine mists of heavily-refined chemicals. For [Ruth Amos], a $78,000 LED bed had caught her eye, and she wondered if she could recreate the same functionality on the cheap.

The concept behind [Ruth]’s build is simple enough. Rather than buy a crazy-expensive off-the-shelf beauty product, she decided to just buy equivalent functional components: a bunch of cheap red LEDs. Then, all she had to do was build these into a facemask and loungewear set to get the same supposed skin improving benefits at much lower cost.

[Ruth] started her build with a welding mask, inside which she fitted red LED strips of the correct wavelength for beneficial skin effects. She then did the same with an over-sized tracksuit, lacing it with an array of LED strips to cover as much of the body as possible. While it’s unlikely she was able to achieve the same sort of total body coverage as a full-body red light bed, nor was it particularly comfortable—her design cost a lot less—on the order of $100 or so.

Of course, you might question the light therapy itself. We’re not qualified to say whether or not red LEDs will give you better skin, but it’s not the first time we’ve seen a DIY attempt at light therapy. Continue reading “DIY Your Own Red Light Therapy Gear” →

Cheap Fiber Optic Wand Toy Becomes Tiny Weird Display

February 28, 2025 by 11 Comments

If you’ve ever seen those cheap LED fiber optic wands at the dollar store, you’ve probably just thought of them as a simple novelty. However, as [Ancient] shows us, you can turn them into a surprisingly nifty little display if you’re so inclined.

The build starts by removing the fiber optic bundle from the wand. One end is left as a round bundle. At the other end, the strands are then fed into plastic frames to separate them out individually. After plenty of tedious sorting, the fibers are glued in place in a larger rectangular 3D-printed frame, which holds the fibers in place over a matrix of LEDs. The individual LEDs of the matrix light individual fibers, which carry the light to the round end of the bundle. The result is a tiny little round display driven by a much larger one at the other end.

[Ancient] had hoped to use the set up for a volumetric display build, but found it too fragile to be fit for purpose. Still, it’s interesting to look at nonetheless, and a good demonstration of how fiber optics work in practice. As this display shows, you can have two glass fibers carrying completely different wavelengths of light right next to each other without issue.

We’ve featured some other great fiber optic hacks over the years, like this guide on making your own fiber couplings. Video after the break.

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Powerful Flashlight Gets Active Air Cooling

February 9, 2025 by 17 Comments

LEDs were once little more than weedy little indicators with low light output. Today, they’re absolute powerhouses, efficiently turning a flow of electrons into a searing beam of light. Despite their efficiency, they can still put out a fair whack of heat. Thus, if you’re building a powerful flashlight like [CrazyScience], you might wanna throw some active cooling on there just to keep things happy. Check out the video below.

The build will not be unfamiliar to any casual observer of the modern DIY flashlight scene. It uses a flatpack LED module of great brightness and a wad of 18650 lithium-ion cells to provide the juice to run it. The LED itself is mounted in a 3D-printed frame, which leaves its rear exposed, and a small PC fan is mounted for air cooling. It’s not the most optimized design, as airflow out of the fan is somewhat restricted by the 3D-printed housing, but it’s a lot better than simple passive cooling. It allows the torch to be more compact without requiring a huge heatsink to keep the LED at an acceptable temperature.

The final torch doesn’t have the most ergonomic form factor, but it does work. However, as a learning project for a new maker, it’s a start, and the learning value of building something functional can’t be understated. If your desire for flashlights swerves to the more powerful, we’ve covered those, too. Just be careful out there.

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