LayerLapse Simplifies 3D Printer Time-lapse Shots

April 8, 2025 by Tom Nardi 15 Comments

We know you’ve seen them: the time-lapses that show a 3D print coming together layer-by-layer without the extruder taking up half the frame. It takes a little extra work compared to just pointing a camera at the build plate, but it’s worth it to see your prints materialize like magic.

Usually these are done with a plugin for OctoPrint, but with all due respect to that phenomenal project, it’s a lot to get set up if you just want to take some pretty pictures. Which is why [Whopper Printing] put together the LayerLapse. This small PCB is designed to trigger your DSLR or mirrorless camera once its remotely-mounted hall effect sensor detects the presence of a magnet.

The idea is that you just need to stick a small magnet to your extruder, add a bit of extra G-code that will park it over the sensor at the end of each layer, and you’re good to go. There’s even a spare GPIO pin broken out should you want to trigger something else on each layer of your print. Admittedly we can’t think of anything else right now that would make sense, other than some other type of camera, but we’re sure some creative folks out there could put this feature to use.

Currently, [Whopper Printing] is selling the LayerLapse as a finished product, though it does sound like a kit version is in the works. There’s also instructions for building a DIY version of the hardware using your microcontroller of choice. Whether you buy or build the hardware, the firmware is available under the MIT license for your tinkering pleasure.

Being hardware hackers, we appreciate the stand-alone nature of this solution. But if you’re already controlling your printer through OctoPrint, you’re probably better off just setting up one of the available time-lapse plugins.

A Low F Number Lens, From Scratch

April 6, 2025 by Jenny List 54 Comments

The F-number of a photographic lens is a measure of its light-gathering ability, and is expressed as its aperture diameter divided by its focal length. Lenses with low F-numbers are prized by photographers for their properties, but are usually expensive because making a good one can be something of a challenge. Nevertheless [Rulof] is giving it a go, making an 80mm F0.5 lens with a Sony E-mount. The video below the break has all the details, and also serves as a fascinating primer on lens design if you are interested.

Rather than taking individual lenses, he’s starting with the second-hand lens from an old projector. It’s got the required huge aperture, but it’s by no means a photographic lens. An interesting component is his choice of diaphragm for the variable aperture, it’s a drafting aid for drawing circles which closely resembles a photographic part. This is coupled with the triplet from an old SLR lens in a 3D-printed enclosure, and the result is a lens that works even if it may not be the best. We know from experiences playing with lens systems that adjusting the various components of a compound lens like this one can be very difficult; we can see it has the much sought-after bokeh or blurred background, but it lacks sharpness.

Perhaps because a camera is an expensive purchase, we don’t see as much of this kind of hacking as we’d like. That’s not to say that lenses don’t sometimes make their way here.

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Zink Is Zero Ink — Sort Of

March 31, 2025 by Al Williams 37 Comments

When you think of printing on paper, you probably think of an ink jet or a laser printer. If you happen to think of a thermal printer, we bet you think of something like a receipt printer: fast and monochrome. But in the last few decades, there’s been a family of niche printers designed to print snapshots in color using thermal technology. Some of them are built into cameras and some are about the size of a chunky cell phone battery, but they all rely on a Polaroid-developed technology for doing high-definition color printing known as Zink — a portmanteau of zero ink.

For whatever reason, these printers aren’t a household name even though they’ve been around for a while. Yet, someone must be using them. You can buy printers and paper quite readily and relatively inexpensively. Recently, I saw an HP-branded Zink printer in action, and I wasn’t expecting much. But I was stunned at the picture quality. Sure, it can’t print a very large photo, but for little wallet-size snaps, it did a great job.

The Tech

Polaroid was well known for making photographic paper with color layers used in instant photography. In the 1990s, the company was looking for something new. The Zink paper was the result. The paper has three layers of amorphochromic dyes. Initially, the dye is colorless, but will take on a particular color based on temperature.

The key to understanding the process is that you can control the temperature that will trigger a color change. The top layer of the paper requires high heat to change. The printer uses a very short pulse, so that the top layer will turn yellow, but the heat won’t travel down past that top layer.

The middle layer — magenta — will change at a medium heat level. But to get that heat to the layer, the pulse has to be longer. The top layer, however, doesn’t care because it never gets to the temperature that will cause it to turn yellow.

The bottom layer is cyan. This dye is set to take the lowest temperature of all, but since the bottom heats up slowly, it takes an even longer pulse at the lower temperature. The top two layers, again, don’t matter since they won’t get hot enough to change. A researcher involved in the project likened the process to fried ice cream. You fry the coating at a high temperature for a short time to avoid melting the ice cream. Or you can wait, and the ice cream will melt without affecting the coating.

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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.

Acoustic Levitation Gets Insects Ready For Their Close-Up

March 22, 2025 by Tom Nardi 6 Comments

The average Hackaday reader is likely at least familiar with acoustic levitation — a technique by which carefully arranged ultrasonic transducers can be used to suspend an object in the air indefinitely. It’s a neat trick, the sort of thing that drives them wild at science fairs, but as the technique only works on exceptionally small and light objects it would seem to have little practical use.

That is, unless, you happen to be interested in exceptionally small and light objects. A paper titled Automated Photogrammetric Close-Range Imaging System for Small Invertebrates Using Acoustic Levitation describes a fascinating device which allows the researchers to image insects in what’s essentially a weightless environment.

With the delicate specimens suspended in front of the lens, there’s no background to worry about and they can be perfectly lit from all angles. What’s more, with careful control of the ultrasonic transducers, it’s possible to control the rotation of the target — allowing researchers to produce 3D scans of the insects using just one camera.

There isn’t a whole lot of technical detail on the device itself, other than the fact that spherical chamber has a radius of 60 mm and is fitted with 96 Murata MA40S4R/S transducers operating at 40 kHz. The paper notes that early attempts to control the transducer array with a Arduino Mega failed, and that the team had to switch over to a FPGA. With their current signal generator stage, the researchers are able to rotate the specimen by 5° angles.

Interested in learning more about acoustic levitation? University of Bristol research scientist Asier Marzo gave a talk on the subject at Hackaday Belgrade in 2018 that you won’t want to miss.

Repairing A Kodak Picture Maker Kiosk

March 15, 2025 by Al Williams 9 Comments

Photo-printing kiosks are about as common as payphones these days. However, there was a time when they were everywhere. The idea was that if you didn’t have a good printer at home, you could take your digital files to a kiosk, pay your money, and run off some high-quality images. [Snappiness] snagged one, and if you’ve ever wondered what was inside of one, here’s your chance.

While later models used a Windows PC inside, this one is old enough to have a Sun computer. That also means that it had things like PCMCIA slots and a film scanner. Unfortunately, it wasn’t working because of a bad touch screen. The box was looking for a network on boot, which required some parameter changes. The onboard battery is dead, too, so you have to change the parameters on every boot. However, the real killer was the touchscreen, which the software insists on finding before it will start.

The monitor is an old device branded as a Kodak monitor and, of course, is unavailable. [Snappiness] found pictures of another kiosk online and noted that the monitor was from Elo, a common provider of point-of-sale screens. Could the “Kodak” monitor just be an Elo with a new badge? It turns out it probably was because a new Elo monitor did the trick.

Of course, what excited us was that if we found one of these in a scrap pile, it might have a Sun workstation inside. Of course, you can just boot Solaris on your virtual PC today. You might be surprised that Kodak invented the digital camera. But they failed to understand what it would mean to the future of photography.

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Make Your Cheap Thermal Camera Into A Microscope

March 14, 2025 by Al Williams 17 Comments

[Project 326] has a cheap thermal camera that plugs into a smart phone. Sure they are handy, but what if you could hack one into a microscope with a resolution measured in microns? It is easier than you might think and you can see how in the video below.

Of course, microscopes need lenses, but glass doesn’t usually pass IR very well. This calls for lenses made of exotic material like germanium. One germanium lens gives some magnification. However, using a 3D printed holder, three lenses are in play, and the results are impressive.

The resolution is good enough to see the turns of wire in an incandescent light bulb. A decapsulated power transistor was interesting to view, too. Imaging heat at that much resolution gives you a lot of information. At the end, he teases that using first surface mirrors, he may show how to build an IR telescope as well.

Presumably, this will work with just about any IR camera if you adapt the lens holder. The unit in the video is a UNI-T UTi-260M. So when he says he spent about $35 on the build, that’s not including the $400 or so camera module.

IR imaging can pull off some amazing tricks, like looking inside an IC. If the thermal camera used in the video isn’t to your liking, there are plenty of others out there.

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