Put Plasma to Work with this Basic Toolkit

Fair warning: [Justin Atkin]’s video on how to make plasma, fusors, and magnetrons is a bit long. But it’s worth watching because he’s laying a foundation for a series of experiments with plasma, which looks like it will be a lot of fun.

After a nice primer on the physics of plasma, [Justin] goes into some detail about the basic tools of the trade: high voltage and high vacuum. A couple of scrap microwave oven transformers, a bridge rectifier, and a capacitor provide the 2000 volts DC output needed. It’s a workable setup, but we’ll take issue with the incredibly dangerous “scariac” autotransformer, popularized by [The King of Random]. It seems foolish to risk a painful death mixing water and line current when a 20-amp variac can be had for $100.

A decent vacuum pump will be needed too, of course; perhaps the money you can save by building your own Sprengel vacuum pump can be put toward the electrical budget. Vacuum chambers are cheap too — Mason jars with ground rims and holes drilled for accessories like spark plugs. Magnets mounted below one chamber formed a rudimentary magnetron, thankfully without the resonating cavities needed for producing microwaves. Another experiment attempted vapor deposition of titanium nitride.

It’s all pretty cool stuff, and we’re looking forward to more details and results. While we wait, feel free to check out the tons of plasma projects we’ve featured, from tiny plasma speakers to giant plasma tubes.

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Easy DIY Microfluidics

Microfluidics, the precise control and manipulation of small volumes of liquids, is heavily used in any field that does small-scale experiments with expensive reagents (We’re looking at you, natural sciences.) However, the process commonly used to create microfluidic devices is time and experience intensive. But, worry not: the Uppsala iGEM team has created Chipgineering: A manual for manufacturing a microfluidic chip.

Used while developing everything from inkjet print heads to micro-thermal technologies, microfluidic systems are generally useful. Specifically, Uppsala’s microfluidic device performs a simple biological procedure, a heat-shock transformation, as a proof of concept. Moreover, Uppsala uses commonly available materials: ready to pour PDMS (a biologically compatible silicon) and a 3D printed mold. Additionally, while the team used a resin 3D printer, there seems to be little reason that a fused deposition modeling (FDM) printer wouldn’t work just as well. Particularly interesting is how they sandwich their PDMS between two plates, potentially allowing easy removal and replacement of reagents without external mechanisms. And, to put the cherry on top, Uppsala’s well-illustrated documentation is a joy to read.

This isn’t the first time we’ve covered microfluidic devices, and if you’re still in the prototyping phase, these microfluidic LEGO-like blocks might be what you need. But, if you prefer macrofluidics, this waste shark that aims to clean our oceans might be more your style.

High Vacuum with Mercury and Glassware

If you want to build your own vacuum tubes, whether amplifying, Nixie or cathode-ray, you’re going to need a vacuum. It’s in the name, after all. For a few thousand bucks, you can probably pick up a used turbo-molecular pump. But how did they make high vacuums back in the day? How did Edison evacuate his light bulbs?

Strangely enough, you could do worse than turn to YouTube for the answer: [Cody] demonstrates building a Sprengel vacuum pump (video embedded below). As tipster [BrightBlueJim] wrote us, this project has everything: high vacuum, home-made torch glassware, and large quantities of toxic heavy metals. (Somehow [Jim] missed out on the high-voltage from the static electricity generated by sliding mercury down glass tubes for days on end.)

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Measuring Tiny Masses Acoustically

How do you measure the mass of something really, really tiny? Like fish-embryo tiny. There aren’t many scales with the sensitivity and the resolution to make meaningful measurements in the nanogram range, so you’ve got to turn to other methods, like measuring changes in the resonant frequency of a glass tube. And that turns out to be cheap and easy for the home gamer to reproduce.

In a recent scholarly paper, [William Grover] et al from the University of California Riverside outline the surprisingly simple and clever method of weighing zebrafish embryos, an important model organism used in all sorts of developmental biology and environmental research. [Grover]’s method is a scaled-up version of a suspended microchannel resonator (SMR), a microelectromechanical device that can measure the mass of single cells or even weigh a virus particle. Rather than etch the resonator out of silicon, a U-shaped glass tube is vibrated by a piezoelectric speaker and kept at its resonant frequency by feedback from a cheap photointerrupter. When an embryo is pumped into the tube, the slight change in mass alters the resonant frequency of the system, which is easily detected by the photointerrupter. The technique can even be leveraged to measure volume and density of the embryos, and all for about $12 in parts.

In the lab, [Grover]’s team uses a data acquisition card and LabVIEW to run the resonant loop, but there’s no reason a DIY version of this couldn’t use an Arduino. In fact, tipster [Douglas Miller] expects someone out there will try this, and would appreciate hearing the details. You can ping him on his hackaday.io page.

Heat Shrink Tubing and the Chemistry Behind Its Magic

There’s a lot to be said in favor of getting kids involved in hacking as young as possible, but there is one thing about working in electronics that I believe is best left as a mystery until at least the teenage years — hide the shrink tube. Teach them to breadboard, have them learn resistor color codes and Ohm’s Law, and even teach them to solder. But don’t you dare let them near the heat shrink tubing. Foolishly reveal that magical stuff to kids, and if there’s a heat source anywhere nearby I guarantee they’ll blow through your entire stock of the expensive stuff the minute you turn your back. Ask me how I know.

I jest, but only partly. There really is something fun about applying heat shrink tubing, and there’s no denying how satisfying a termination can be when it’s hermetically sealed inside that little piece of inexplicably expensive tubing. But how does the stuff even work in the first place?

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Souped-Up, Next Gen Wearables

The biggest hurdle to great advances in wearable technology is the human body itself. For starters, there isn’t a single straight line on the thing. Add in all the flexing and sweating, and you have a pretty difficult platform for innovation. Well, times are changing for wearables. While there is no stock answer, there are some answers in soup stock.

A group of scientists at Stanford University’s Bao Lab have created a whisper thin co-polymer with great conductivity. That’s right, they put two different kinds of insulators together and created a conductor. The only trouble was that the resulting material was quite rigid. With the help of some fancy x-ray equipment, they discovered that adding a molecule found in standard industrial soup thickeners stops the crystallization process of the polymers, leaving them flexible and stretchy. Get this: the material conducts even better when stretched.

The scientists have used the material to make both simple, transparent electrodes as well as entire flexible transistor arrays with an inkjet printer. They hope to influence next generation wearable technology for everything from smart clothing to medical devices. Who knows, maybe they can team up with the University of Rochester and create a conducting co-polymer that can also shape-shift. Check out a brief demonstration after the break.

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LEGO Liquid Handler and Big Biology

A career as a lab biologist can take many forms, but the general public seems to see it as a lone, lab-coated researcher sitting at a bench, setting up a series of in vitro experiments by hand in small tubes or streaking out a little yeast on an agar plate. That’s not inaccurate at all – all of us lab rats have done time with a manual pipettor while trying to keep track of which tube in the ice bucket gets which solution. It’s tedious stuff.

But because biology experiments generally scale well, and because more data often leads to better conclusions, life science processes can quickly grow beyond what can be handled manually. I’ve seen this time and again in my 25 years in science, from my crude grad school attempts to miniaturize my assays and automate data collection to the multi-million dollar robotic systems I built in my career in the pharmaceutical industry. Biology can get pretty big in a hurry. Continue reading “LEGO Liquid Handler and Big Biology”