HDD Centrifuge Puts COVID-19 Testing Lab In A Backpack

February 5, 2022 by Dan Maloney 11 Comments

Throughout this two-year global COVID-19 nightmare, one thing that has been sorely lacking is access to testing. “Flu-like symptoms” covers a lot of ground, and knowing if a sore throat is just a sore throat or something more is important enough that we’ve collectively plowed billions into testing. Unfortunately, the testing infrastructure remains unevenly distributed, which is a problem this backpack SARS-CoV-2 testing lab aims to address.

The portable lab, developed by [E. Emily Lin] and colleagues at the Queen Mary University of London, uses a technique called LAMP, for loop-mediated isothermal amplification. LAMP probably deserves an article of its own to explain the process, but suffice it to say that like PCR, LAMP amplifies nucleic acid sequences, but does so without the need for expensive thermal cycling equipment. The kit contains a microcentrifuge that’s fashioned from an e-waste hard drive, a 3D printed rotor, and an Arduino to drive the motor and control the speed. The centrifuge is designed to run on any 12 VDC source, meaning the lab can be powered by a car battery or solar panel if necessary. Readout relies on the trusty Mark I eyeball and a pH-indicating buffer that changes color depending on how much SARS-CoV-2 virus was in the sample.

Granted, the method used here still requires more skill to perform than a simple “spit on a stick” rapid antigen test, and it’s somewhat more subjective than the “gold standard” quantitative polymerase chain reaction (qPCR) assay. But the method is easily learned, and the kit’s portability, simple design, and low-cost construction could make it an important tool in attacking this pandemic, or the next one.

Thanks to [Christian Himmler] for the tip.

Experiments With A Nernst Lamp

December 22, 2021 by Al Williams 14 Comments

Every biography of Edison talks about how the secret to the incandescent lamp was to remove the air from the bulb. That’s true when you use conventional filaments, but a man named Nernst found that using a filament that was already oxidized would allow you to create a lamp that would operate fine in the normal atmosphere. [Jaynes Network] takes a look at these oddities which date back to the 1800s in a recent video that you can see below.

The lamps use a ceramic filament, but the downside is that the filament needs to be hot to allow the lamp to work. The experiment takes a zirconium oxide rod and attempts to light it up. The heat source is a propane torch.

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A Glowing Potato Peeler Makes A Nernst Lamp

October 2, 2021 by Jenny List 18 Comments

Over the last couple few decades there has been a great shift in electric lighting, first towards more compact and efficient fluorescent lights, and then towards LED bulbs. The old incandescent bulbs, while giving a pleasant light, were not by any means efficient. Digging into the history books the incandescent bulb as we know it was not the only game in town; while suspending a filament in a vacuum stopped it from being oxidized there was another type of light that used a ceramic element at atmospheric pressure. The Nernst lamp required its filament to be heated before it would conduct electricity, and [Drop Table Adventures] has made one using the blade from a ceramic potato peeler.

The right ceramic is not the problem given the ease of finding ceramic kitchen utensils, but two problems make a practical light difficult. The copper connections themselves become too hot and oxidize, and preheating the ceramic with a blowtorch is difficult while also keeping an even heat. Finally, they do manage a self-sustaining lamp, albeit not the brightest one.

If you think the Nernst lamp sounds familiar, maybe it’s because we covered it as part of our retrotechtacular series.

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Big 3D-Printed Lamp Tries Some New Features

July 14, 2021 by Donald Papp 10 Comments

In lamp design, bulbs are usually given generous clearances because they get hot during use. LED bulbs however give off comparatively little heat, which opens a few new doors. [Mark Rehorst] created this huge 3D printed lamp, made with his custom 3D printer and a hefty 1 mm diameter nozzle, and the resulting device not only looks great, but shows off a few neat design features.

The LED filament bulb doesn’t give off much heat, so a PETG partial shade mounted directly to the bulb works fine.

[Mark] printed a partial shade in PETG that is made to sit directly on the bulb itself. The back of the shade is open, allowing light to spill out from behind while the front of the bulb is shielded, making it easier on the eyes. The result is pretty nifty, as you can see here. It sits in the center of the 600 mm tall lamp, which takes up most of the build volume of his self-made CoreXY-based printer, the UMMD.

The LED filament strands in this style of bulb are pretty neat in their own way, and some of you may remember that when they first became available as separate components, no time was lost in finding out what made them tick.

Lithophane Lamp Has Us Over The Moon

May 21, 2021 by Lewin Day 7 Comments

Lithophanes are artistic creations which rely on the varying thickness of a material that is then backlit to reveal an image. While these were often made in porcelain in the past, these days we have the benefit of 3D printing on our side. The principle can be deftly applied to everything from flat planes to spheres, with [Tiffany Lo] demonstrating a great application of the latter with her 3D printed moon lamp.

The basic concept is to take a 2D image of the lunar surface, and then use it to generate a height mapped sphere for 3D printing. When lit from within, the sphere will appear as per the surface of the moon. The sphere geometry was generated with the Lithophane Sphere Maker online tool combined with NASA data of the moon intended for computer graphics purposes. The sphere was then printed on a typical FDM printer before being assembled upon a base with LEDs inside for backlighting.

The result is an attractive moon lamp that both recalls the heavy rock that follows us in a tidally-locked orbit, and yet can be switched off at night to make it easier to sleep. Unfortunately, it’s impractical to turn off the shine from the real moon, and we suspect nobody is working on the problem.

We’ve seen other moon lamps before; they’re a great starting point because the moon’s greyscale tones work well as a lithograph. More advanced techniques are likely necessary for those eager to create lamps of the gas giants; if you’ve done so, be sure to drop us a line.

Lamps Double As Secret Surround Sound Speakers

April 28, 2021 by Tom Nardi 23 Comments

Combined with today’s massive flat panel displays, a nice surround sound system can provide an extremely immersive environment for watching movies or gaming. But a stumbling block many run into is speaker placement. The front speakers generally just go on either side of the TV, but finding a spot for the rear speakers that’s both visually and acoustically pleasing can be tricky.

Which is why [Peter Waldraff] decided to take a rather unconventional approach and hide his rear surround sound speakers in a pair of functioning table lamps. This not only looks better than leaving the speakers out, but raises them up off the floor and into a better listening position. The whole thing looks very sleek thanks to some clever wiring, to the point that you’d never suspect they were anything other than ordinary lamps.

The trick here is the wooden box located at the apex of the three copper pipes that make up the body of the lamp. [Peter] mounted rows of LEDs to the sides of the box that can be controlled with a switch on the bottom, which provides light in the absence of a traditional light bulb. The unmodified speaker goes inside the box, and connects to the audio wires that were run up one of the pipes.

In the base, the speaker and power wires are bundled together so it appears to be one cable. Since running the power and audio wires together like this could potentially have resulted in an audible hum, [Peter] only ran 12 VDC up through the lamp to the LEDs and used an external “wall wart” transformer. For convenience, he also put a USB charging port in the center of the base.

When speakers or surround sound systems pass our way, it’s usually because some hacker has either made a set from scratch, or has added some new and improved capabilities to their existing gear. This project may be a bit low-tech compared to some that have graced these pages, but it’s undoubtedly a clever and unexpected solution to the problem, and that’s a hack in our book.

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Cassette Lamp Is A Throwback To The Pencil-Winding Glory Days

March 17, 2021 by Lewin Day 18 Comments

The audio cassette was the first music format that truly championed portability. It was robust, compact, and let people take music on the go to soundtrack their very lives. It was later supplanted by the higher-quality CD and then further digital technologies, but the format remains a nostalgic highlight for many. It also inspired this excellent lamp build from [Fab].

The lamp consists of 8 clear cassettes assembled into a rough cube-like shape on a 3D printed frame. The cassettes are edge-lit from below by a set of WS2812B LEDs, letting them glow in full-color splendour. The real magic of the lamp is the interface, however. A pencil can be inserted to turn the tape reels, just like rewinding a real cassette. However, in this case, they’re attached to a pair of rotary encoders, which are used to vary the color of the LEDs. As a bonus, the entire lamp runs off a Wemos D1, making it possible to update the lamp remotely over the Internet.

It’s a stylish build that would make an excellent conversation piece in any hip maker’s loungeroom. It’s a great nod to the creator of the compact cassette, [Lou Ottens], who passed away earlier this month. Video after the break.

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