An Artificial Sun In A Manageable Size

March 28, 2025 by Jenny List 8 Comments

The sun is our planet’s source of natural illumination, and though we’ve mastered making artificial light sources, it remains extremely difficult to copy our nearby star. As if matching the intensity wasn’t enough, its spectral quality, collimation, and atmospheric scattering make it an special challenge. [Victor Poughon] has given it a go though, using a bank of LEDs and an interesting lens system.

We’re used to lenses being something that can be bought off-the-shelf, but this design eschews that convenience by having the lenses manufactured and polished as an array, by JLC. The scattering is taken care of by a sheet of inkjet printer film, and the LEDs are mounted on a set of custom PCBs.

The result is certainly a very bright light, and one whose collimation delivers a sun-like effect of coming from a great distance. It may not be as bright as the real thing, but it’s certainly something close. If you’d like something to compare it to, it’s not the first such light we’ve featured.

Scanning Film The Way It Was Meant To Be

March 28, 2025 by Jenny List 37 Comments

Scanning a film negative is as simple as holding it up against a light source and photographing the result. But should you try such a straightforward method with color negatives it’s possible your results may leave a little to be desired. White LEDs have a spectrum which looks white to our eyes, but which doesn’t quite match that of the photographic emulsions.

[JackW01] is here with a negative scanning light that uses instead a trio of red, green, and blue LEDs whose wavelengths have been chosen for that crucial match. With it, it’s possible to make a good quality scan with far less post-processing.

The light itself uses 665 nm for red, 525 nm for green, and 450 nm blue diodes mounted in a grid behind a carefully designed diffuser. The write-up goes into great detail about the spectra in question, showing the shortcomings of the various alternatives.

We can immediately see the value here at Hackaday, because like many a photographer working with analogue and digital media, we’ve grappled with color matching ourselves.

This isn’t the first time we’ve considered film scanning but it may be the first project we’ve seen go into such detail with the light source. We have looked at the resolution of the film though.

AqMood Is An Air Quality Monitor With An Attitude

March 27, 2025 by Tom Nardi No comments

You take your air quality seriously, so shouldn’t your monitoring hardware? If you’re breathing in nasty VOCs or dust, surely a little blinking LED isn’t enough to express your displeasure with the current situation. Luckily, [Tobias Stanzel] has created the AqMood to provide us with some much-needed anthropomorphic environmental data collection.

To be fair, the AqMood still does have its fair share of LEDs. In fact, one might even say it has several device’s worth of them — the thirteen addressable LEDs that are run along the inside of the 3D printed diffuser will definitely get your attention. They’re sectioned off in such a way that each segment of the diffuser can indicate a different condition for detected levels of particulates, VOCs, and CO2.

But what really makes this project stand out is the 1.8 inch LCD mounted under the LEDs. This display is used to show various emojis that correspond with the current conditions. Hopefully you’ll see a trio of smiley faces, but if you notice a bit of side-eye, it might be time to crack a window. If you’d like a bit more granular data its possible to switch this display over to a slightly more scientific mode of operation with bar graphs and exact figures…but where’s the fun in that?

[Tobias] has not only shared all the files that are necessary to build your own AqMood, he’s done a fantastic job of documenting each step of the build process. There’s even screenshots to help guide you along when it’s time to flash the firmware to the XIAO Seeed ESP32-S3 at the heart of the AqMood.

If you prefer your air quality monitoring devices be a little less ostentatious, IKEA offers up a few hackable models that might be more your speed.

Chase Light SAO Shouldn’t Have Used A 555, And Didn’t

March 27, 2025 by Dan Maloney 13 Comments

Around these parts, projects needlessly using a microcontroller where a simpler design would do are often derided with the catch-all “Should have used a 555,” even if the venerable timer chip wouldn’t have been the ideal solution. But the sentiment stands that a solution more complicated than it needs to be is probably one that needs rethinking, as this completely mechanical chaser light badge Simple Add-On (SAO) aptly demonstrates.

Rather than choosing any number of circuits to turn a strip of discrete lights on and off, [Johannes] took inspiration for his chaser lights from factory automation mechanisms that move parts between levels on steps that move out of phase with each other, similar to the marble-raising mechanism used in [Wintergatan]’s Marble Machine X.

Two thin plates with notches around the edge are sandwiched together inside the 3D printed case of the SAO, between the face and the light source. A small motor and a series of gears rotate the two masks 180° out of phase with each other, which creates the illusion that the light is moving.

It’s pretty convincing; when we first saw the video below, we were sure it was a row of tiny LEDs around the edge of the badge.

Hats off to [Johannes] for coming up with such a clever mechanism and getting it working just in time for Hackaday Europe. If you need to catch up on the talks, we’ve got a playlist ready for you.

Continue reading “Chase Light SAO Shouldn’t Have Used A 555, And Didn’t” →

LED Filaments Become Attractive Time Piece

March 25, 2025 by Lewin Day 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.

Continue reading “LED Filaments Become Attractive Time Piece” →

DIY Your Own Red Light Therapy Gear

March 18, 2025 by Lewin Day 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” →

Some Useful Notes On The 6805-EC10 Addressable RGB LED

March 12, 2025 by Dave Rowntree 9 Comments

LEDs are getting smaller and smaller, and the newest generations of indexable RGB LEDs are even fiddlier to use than their already diminutive predecessors. [Alex Lorman] has written some notes about the minuscule SK6805-EC10 series of LEDs, which may be helpful to those wanting to learn how to deal with these in a more controlled manner.

Most hardware types will be very familiar with the 5050-sized devices, sold as Neopixels in some circles, which are so-named due to being physically 5.0 mm x 5.0 mm in the horizontal dimensions. Many LEDs are specified by this simple width by depth manner. As for addressable RGB LEDs (although not all addressable LEDs are RGB, there are many weird and wonderful combinations out there!) the next most common standard size down the scale is the 2020, also known as the ‘Dotstar.’ These are small enough to present a real soldering challenge, and getting a good placement result needs some real skills.

[Alex] wanted to use the even smaller EC10 or 1111 devices, which measure a staggering 1.1 mm x 1.1 mm! Adafruit’s product page mentions that these are not intended for hand soldering, but we bet you want to try! Anyway, [Alex] has created a KiCAD footprint and a handy test PCB for characterizing and getting used to handling these little suckers, which may help someone on their way. They note that hot air reflow soldering needs low temperature paste (this scribe recommends using MG Chemicals branded T3 Sn₄₂Bi₅₇Ag₁ paste in this application) and a very low heat to avoid cracking the cases open. Also, a low air flow rate to prevent blowing them all over the desk would also be smart. Perhaps these are more suited to hot plate or a proper convection oven?

As a bonus, [Alex] has previously worked with the slightly larger SK6805-1515 device, with some good extra notes around an interesting nonlinearity effect and the required gamma correction to get good colour perception. We’ll leave that to you readers to dig into. Happy soldering!

We’ve not yet seen many projects using these 1111 LEDs, but here’s one we dug up using the larger 1515 unit.