Open Microfluidics Instrumentation Playset

Micro-what? Microfluidics! It’s the field of dealing with tiny, tiny bits of fluids, and there are some very interesting applications in engineering, biology, and chemistry. [Martin Fischlechner], [Jonathan West], and [Klaus-Peter Zauner] are academic scientists who were working on microfluidics and made their own apparatus, initially because money was tight. Now they’ve stuck to the DIY approach because they can get custom machinery that simply doesn’t exist.

In addition to their collaboration, and to spread the ideas to other labs, they formed DropletKitchen to help advance the state of the art. And you, budding DIY biohacker, can reap the rewards.

In particular, the group is focused on droplet microfluidics. Keeping a biological or chemical reaction confined to its own tiny droplet is like running it inside its own test-tube, but because of the high rate at which the droplets can be pumped out, literally millions of these test-tubes are available. Want to grow hundreds of thousands of single cells, each in their own environment? Done.

The DropletKitchen kit includes an accurate pump system, along with high-speed camera and flash setups to verify that everything’s working as it should. Everything is open-source, and a lot of it is 3D-printable and written in OpenSCAD so that it’s even easy to modify to fit your exact needs. You just need to bring the science.

This is a professional-grade open source project, and we’re excited to see it when academics take a turn toward the open. Bringing cutting edge processing technologies within reach of the biohacker community is a huge multiplier. We can’t wait to see what comes out of this.

Make Water Bridges With High Voltages

It’s generally a bad idea to mix high voltage electricity and water, but interesting things happen if you do. This video from [RWGResearch] shows one of them: water bridging. If you have two water sources (such as two beakers full of very highly distilled water) with a high voltage between them, the voltage can create a gravity defying bridge that flows between them.

The experiment starts with the pouring spouts from two beakers nearly touching each other. Water fills the beakers right up to the spout, but it’s the application of electricity that pulls the bridge between the positive and negative beakers. With care, this technique can create a bridge of up to 2cm (about 0.8 inches). [RWGResearch] shows that he is able to create a bridge of about a centimeter with a 5KV voltage, but which only carries a few milliamps.

What forces are at play here isn’t exactly clear, but one recent paper speculates that it’s down to a combination of the dielectric force caused by the differing charges of parts of water molecules and the surface tension of the water. Whatever it is, it is fascinating and makes for a neat trick.

Want to make your own contribution to the scientific body of knowledge? Prove or disprove the speculation mentioned in the Wikipeadia article: is this possible because of an H3O2 lattice formed by the high voltage? How would you formulate a test for this?

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Transparent Rocket Engine

Rocket engines are undeniably cool. Experiencing the roar, seeing the fire, and watching the rocket blast off into the sky… what else can you ask for? Well, for [NightHawkInLight], a transparent rocket body is the answer.

Based on previous work by [Applied Science], he uses an acrylic rod as the rocket body and as the fuel. Bring a flame into the acrylic, apply oxygen from a canister at the other end of the body and voilà! The rocket engine starts nicely, and even better, the intensity of the burn can be controlled via the amount of oxygen provided.
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Retrotechtacular: The Golden Book of Chemistry Experiments

Back in “the old days” (that is, when I was a kid), kids led lives of danger and excitement. We rode bikes with no protective gear. We stayed out roaming the streets after dark without adult supervision. We had toy guns that looked like real ones. Dentists gave us mercury to play with. We also blew things up and did other dangerous science experiments.

If you want a taste of what that was like, you might enjoy The Golden Book of Chemistry Experiments. The book, first published in 1960, offers to show you how to set up a home laboratory and provides 200 experiments. The colorfully illustrated book shows you how to do some basic lab work as well as offering some science history and terminology.

Want to make oxygen? There’s several methods on page 27. Page 28 covers making hydrogen. To test the hydrogen for purity, the suggest you collect a test tube full, invert it, and stick a match up to the tube. If the hydrogen is pure it will burn with a pop noise. If air is mixed it, it will explode. Yeah, that sound safe to us.

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Chemical Hacking at a Store Near You

Imagine for a minute that you aren’t an electronic-savvy Hackaday reader. But you find an old chemistry book at a garage sale and start reading it. It has lots of interesting looking experiments, but they all require chemicals with strange exotic names. One of them is ferric chloride. You could go find a scientific supply company, but that’s expensive and often difficult to deal with as an individual (for example, 2.5 liters of nitric acid costs over $300 for a case of six at a common lab supply company). Where would you go?

As an astute electronics guy (or gal) you probably know that ferric chloride is common for PCB etching, so you would check the electronic store down the street or maybe Radio Shack if you are lucky enough to find one that still stocks it.

So sometimes knowing where to look for a chemical is a key part of acquiring it, especially when the names are not the same. For example, do you have any amylose? No? That’s corn starch. Want to try making your own cadmium sulfide light sensor? Go to the art supply store and ask for cadmium yellow pigment. Need magnesium carbonate? Stop by a sporting goods store and ask for athlete’s chalk.

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Acids, Bases and the Power of Hydrogen

The 1970’s was the decade that illuminated the threat of acid rain to the citizens of the US. It had been known to exist several years before, but the sources of the problem did their best to suppress the information. It wasn’t until the environmental damage became significant enough to draw national attention that it would lead to the US enacting regulations to stop acid rain.


Truthfully, most of the public was probably still unaware of what acid rain actually was. The default mental image that comes to the mind of the non-chemist is large drops of battery acid raining down from the heavens and devouring everything. This is not quite the case, however. Pure water has a neutral pH of 7. Normal rain is actually slightly acidic as it picks up CO2 from the air, making carbonic acid. But when this “normal” rain mixes with the byproducts of industrial plants that pump out large amounts of  SO2 (sulfuric dioxide) and NO (nitrogen oxide) into the atmosphere, it becomes even more acidic – down to a pH of 3. This “acid” rain has the acidity of citrus juice, so it’s not going to set the world on fire. But it will wreak havoc on local ecosystems.

The 1990’s brought with it tough government regulations on the output of SO2 and NO by large factories, pretty much eliminating acid rain in the US. The rise and fall of acid rain is a great example of why we should educate ourselves on the basic chemistries that define our lives, even though we might not be actual chemists. In this article, we’re going back to your first year of college and hash out just what defines an acid and base. And solidify our understanding of the pH scale. It is essential for the future biohacker to have this knowledge in their toolbox.

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See if You Can Reverse Engineer This Scrap Metal Battery

We got quite a few tips in about a paper from Vanderbilt about a cool scrap metal battery they’ve been playing with. They made some pretty bold claims and when we fed the numbers in they pretty much say they’ve got a battery you can make at home, that can hold half as much as a lead acid, can be made out of scraps in a cave (even if you’re not Tony Stark), charge super fast,and can cycle 5,000 times without appreciable capacity loss.  Needless to say that’s super cool.

Of course, science research is as broken as ever and the paper was hidden behind a paywall. Through mysterious powers such as the library and bothering people we were able to get past this cunning defense and read the paper. Unfortunately the paper reads more like a brag track than a useful experimental guide on how to build the dang battery. It’s also possible that our copy was missing some pages. Anyway, we want to do science!

Anyway, here’s what we know. The battery is based on an ancient battery called the Baghdad Battery. The ancient battery supposedly used iron and copper with a mystery electrolyte. The scrap battery, however, is made from scrap iron and scrap brass. The iron makes sense, but why brass? Well, brass has copper in it, and you can still get at it chemically even if it’s alloyed.

To that end, the next step was to throw some oxygen atoms in with those pesky Fe and Cu ones. The goal is to get a redox reaction going. If you do it right you can achieve pseudocapacitance. To to this the researchers used “common household chemicals and voltages” to anodize the iron and copper inside the brass. The press photo have them holding a gallon of muratic acid, if that helps. We don’t know, but if they can jam a few oxygen atoms in there then so can we!

After that it’s all about sitting the electrodes in a bath of potassium hydroxide. We guess you can scrape the inside of an AA for that. Anyway, the paper’s light on process but the battery seems really cool. They’re not pursuing this research for commercialization, instead going the OSHW route. They hope to get to the point where anyone can just grind up a bunch of scrap steel and brass, maybe throw it in a birdcage, anodize it, and get a super long life battery for grid use for less than a lead acid. If any of you manage to build one of these drop us a tip!