How Do You Etch Something You Can’t Move?

We probably don’t need to tell this to the average Hackaday reader, but we’re living in a largely disposable society. Far too many things are built as cheaply as possible, either because manufacturers know you won’t keep it for long, or because they don’t want you to. Of course, the choice if yours if you wish to you accept this lifestyle or not.

Like many of us, [Erik] does not. When the painted markings on his stove become so worn that he couldn’t see them clearly, he wasn’t about to hop off to the appliance store to buy a new one. He decided to take things into his own hands and fix the poor job the original manufacturers did in the first place. Rather than paint on new markings, he put science to work and electroetched them into the metal.

Whether or not you’ve got a stove that needs some sprucing up, this technique is absolutely something worth adding to your box of tricks. Using the same methods that [Erik] did in his kitchen, you could etch an awesome control panel for your next device.

So how did he do it? Despite the scary multisyllabic name, it’s actually quite easy. Normally the piece to be etched would go into a bath of salt water for this process, but obviously that wasn’t going to work here. So [Erik] clipped the positive clamp of a 12 V battery charger to the stove itself, and in the negative clamp put a piece of gauze soaked in salt water. Touching the gauze to the stove would then eat away the metal at the point of contact. All he needed to complete the project were some stencils he made on a vinyl cutter.

We’ve previously covered using electricity to etch metal in the workshop, as well as the gorgeous results that are possible with acid etched brass. Next time you’re looking to make some permanent marks in a piece of metal, perhaps you should give etching a try.

[via /r/DIY]

Spectrometer Is Inexpensive And Capable

We know the effect of passing white light through a prism and seeing the color spectrum that comes out of the other side. It will not be noticeable to the naked eye, but that rainbow does not fully span the range of [Roy G. Biv]. There are narrowly absent colors which blur together, and those missing portions are a fingerprint of the matter the white light is passing through or bouncing off. Those with a keen eye will recognize that we are talking about spectrophotometry which is identifying those fingerprints and determining what is being observed and how much is under observation. The device which does this is called a spectrometer and [Justin Atkin] invites us along for his build. Video can also be seen below.

Along with the build, we learn how spectrophotometry works, starting with how photons are generated and why gaps appear in the color spectrum. It is all about electrons, which some of our seasoned spectrometer users already know. The build uses a wooden NanoDrop style case cut on a laser engraver. It needs some improvements which are mentioned and shown in the video so you will want to have some aluminum tape on hand. The rest of the bill of materials is covered including “Black 2.0” which claims to be the “mattest, flattest, black acrylic paint.” Maybe that will come in handy for other optical projects. It might be wise to buy first surface mirrors cut to size, but you can always make bespoke mirrors with carefully chosen tools.

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A Crash Course In 3D Printed Venturi Pumps

Venturi pumps, commonly referred to as aspirators, are a fantastic way of moving around things which you might not want spinning around inside of a pump, and one of the easiest ways to create a vacuum. According to his research, [Tuval Ben Dosa] believed such a device would be a good way to move corrosive gasses which would normally eat up a blower fan; all he had to do was figure out how to 3D print one to his specifications.

Put simply: if you take a “T” shaped pipe and pass a fluid (such as air or water) through the straight section, a vacuum will be created on the shorter side due to the Venturi effect. As long as you don’t mind the substance you wish to pump getting mixed into your working fluid, it’s a simple way to bring something “along for the ride” as the fluid makes its way through the pipe.

[Tuval] needed a way to remove the chlorine gasses produced by his PCB etching station, and an aspirator seemed like the perfect solution. He just needed to pump clean air through a Venturi, which would suck up the chlorine gas on the way through, and ultimately carry it outside. But he soon found that while a pump based on the Venturi effect is simple conceptually, getting it to work in the real world is a bit trickier. Especially when you’re dealing with something like 3D printing, which brings in its own unique challenges.

He tried modeling a few designs he found online in 3D and printing them out, but none of them worked as expected. The most common problem was simply that no vacuum was being generated, air was freely moving out of both sides. While [Tuval] doesn’t claim to have any great knowledge of fluid dynamics, he reasoned that the issue was due to the fact that most Venturi pumps seem designed to move water rather than air. So he designed a new version of the pump which had a more pronounced nozzle on the inlet surrounded by a cavity in which the gases could mix.

His modified design worked, and now anyone with a 3D printer can run off their own Venturi device for quickly and easily giving potentially harmful fumes or gases the boot. If this is one of those things you’d feel more comfortable buying than building, don’t worry, we’ve previously covered using a low-cost aspirator as a vacuum source in the home lab.

Make Your Own Phosphorescent Material

Phosphors are key to a whole swathe of display and lighting technologies. Cathode ray tubes, vacuum fluorsecent displays, and even some white LEDs all use phosphors to produce light. [Hydrogen Time] decided to make a green phosphorescent material, and has shared the process on Youtube, embedded below.

The aim is to produce zinc sulfide crystals doped with copper impurities. This creates a phosphor with a familiar green glow. [Hydrogen Time] starts by noting that it’s important to make sure all chemicals used are of good quality, as even slight impurities can spoil the final product.

Zinc sulfide is made into an aqueous solution, before a highly diluted copper sulfate solution is added, along with ammonium chloride to act as a flux. The mixture is stirred, before being heated in a tube flushed with argon. After firing, the phosphor is washed with water and allowed to cool.

The final product is demonstrated to glow a vibrant green under UV light, showing the process to be successful. [Hydrogen Time] intends to use the homebrew phosphor in future work to produce a display. It recalls us of [Jeri Ellsworth], producing her own EL wire at home. Video after the break.

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A Lemon Battery Via 3D Printing

There are a whole bunch of high school science experiments out there that are useful for teaching students the basics of biology, physics, and chemistry. One of the classics is the lemon battery. [iqless] decided to have a play with the idea, and whipped up a little something for his students.

The basic lemon battery is remarkably simple. Lemon juice provides the electrolyte, while copper and and zinc act as electrodes. This battery won’t have a hope of charging your Tesla, but you might get enough juice to light an LED or small bulb (pun intended).

[iqless] considered jamming electrodes directly into lemons to be rather unsophisticated. Instead, an electrolyte tray was 3D printed. The tray can be filled with lemon juice (either hand-squeezed or straight from a bottle) and the tray has fixtures to hold copper pennies and zinc-plated machine screws to act as the electrodes. The tray allows several cells to be constructed and connected in series or parallel, giving yet further teaching opportunities.

It’s a fun twist on a classroom staple, and we think there are great possibilities here for further experimentation with alternative electrolytes and electrode materials. We’d also love to see a grown-up version with a large cascade of cells in series for lemon-based high voltage experiments, but that might be too much to ask. There’s great scope for using modern maker techniques in classroom science – we’ve discussed variations on the egg drop before. Video after the break.

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Open Source Biological Gear For the Masses

At the risk of putting too fine a point on it, Hackaday exists because people are out there building and documenting open source gadgets. If the person who built a particular gizmo is willing to show the world how they did it, consider us interested. Since you’re reading this, we’ll assume you are as well. Over the years, this mentality has been spreading out from the relatively niche hacker community into the greater engineering world, and we couldn’t be happier.

Case in point, the Poseidon project created at the California Institute of Technology. Developed by students [Sina Booeshaghi], [Eduardo Beltrame], and [Dylan Bannon], along with researcher [Jase Gehring] and professor [Lior Pachter], Poseidon consists of an open source digital microscope and syringe pump which can be used for microfluidics experiments. The system is not only much cheaper than commercial offerings, but is free from the draconian modification and usage restrictions that such hardware often comes with.

Of course, one could argue that major labs have sufficient funding to purchase this kind of gear without having to take the DIY route. That’s true enough, but what benefit is there to limiting such equipment to only the established institutions? As in any other field, making the tools available to a wider array of individuals (from professionals to hobbyists alike) can only serve to accelerate progress and move the state of the art forward.

The Poseidon microscope consists of a Raspberry Pi, touch screen module, and commercially available digital microscope housed in a 3D printed stage. This device offers a large and clear view of the object under the microscope, and by itself makes an excellent educational tool. But when running the provided Python software, it doubles as a controller for the syringe pumps which make up the other half of the Poseidon system.

Almost entirely 3D printed, the pumps use commonly available components such as NEMA 17 stepper motors, linear bearings, and threaded rods to move the plunger on a syringe held in the integrated clamp. Controlled by an Arduino and CNC shield, these pumps are able to deliver extremely precise amounts of liquid which is critical for operations such as Single-cell RNA sequencing. All told a three pump system can be built for less than $400 USD, compared to the tens of thousands one might pay for commercially available alternatives.

The Poseidon project joins a relatively small, but very exciting, list of DIY biology projects that we’ve seen over the years. From the impressive open source CO2 incubator we saw a few years ago to the quick and dirty device for performing polymerase chain reaction experiments, there’s little doubt about it: biohacking is slowly becoming a reality.

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AI Patent Trolls Now on the Job for Drug Companies

Love it or loathe it, the pharmaceutical industry is really good at protecting its intellectual property. Drug companies pour billions into discovering new drugs and bringing them to market, and they do whatever it takes to make sure they have exclusive positions to profit from their innovations for as long a possible. Patent applications are meticulously crafted to keep the competition at bay for as long as possible, which is why it often takes ages for cheaper generic versions of blockbuster medications to hit the market, to the chagrin of patients, insurers, and policymakers alike.

Drug companies now appear poised to benefit from the artificial intelligence revolution to solidify their patent positions even further. New computational methods are being employed to not only plan the synthesis of new drugs, but to also find alternative pathways to the same end product that might present a patent loophole. AI just might change the face of drug development in the near future, and not necessarily for the better.

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