Growing Plants on Mars… on Earth

One of the biggest challenges of traveling to Mars is that it’s far away. That might seem obvious, but that comes with its own set of problems when compared to traveling to something relatively close like the Moon. The core issue is weight, and this becomes a big deal when you have to feed several astronauts for months or years. If food could be grown on Mars, however, this would make the trip easier to make. This is exactly the problem that [Clinton] is working on with his Martian terrarium, or “marsarium”.

The first task was to obtain some soil that would be a good analog of Martian soil. Obtaining the real thing was out of the question, as was getting similar dirt from Hawaii. [Clinton] decided to make his own by mixing various compounds from the hardware store in the appropriate amounts. From there he turned to creating the enclosure and filling it with the appropriate atmosphere. Various gas canisters controlled by gas solenoid valves mixed up the analog to Martian atmosphere: 96% dioxide, 2% argon, and 2% nitrogen. The entire experiment was controlled by an Intel Edison with custom circuits for all of the sensors and regulating equipment. Check out the appropriately dramatic video of the process after the break.

While the fern that [Clinton] planted did survive the 30-day experiment in the marsarium, it wasn’t doing too well. There’s an apparent lack of nitrogen in Martian soil which is crucial for plants to survive. Normally this is accomplished when another life form “fixes” nitrogen to the soil, but Mars probably doesn’t have any of that. Future experiments would need something that could do this for the other plants, but [Clinton] notes that he’ll need a larger marsarium for that. And, if you’re not interested in plants or Mars, there are some other interesting ramifications of nitrogen-fixing as well.

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The Fab Lab Next Door: DIY Semiconductors

You think you’ve got it going on because you can wire up some eBay modules and make some LEDs blink, or because you designed your own PCB, or maybe even because you’re an RF wizard. Then you see that someone is fabricating semiconductors at home, and you realize there’s always another mountain to climb.

We were mesmerized when we first saw [Sam Zeloof]’s awesome garage-turned-semiconductor fab lab. He says he’s only been acquiring equipment since October of 2016, but in that short time he’s built quite an impressive array of gear; a spin-coating centrifuge, furnaces, tons of lab supplies and toxic chemicals, a turbomolecular vacuum pump, and a vacuum chamber that looks like something from a CERN lab.

[Sam]’s goal is to get set up for thin-film deposition so he can make integrated circuits, but with what he has on hand he’s managed to build a few diodes, some photovoltaic cells, and a couple of MOSFETs. He’s not growing silicon crystals and making his own wafers — yet — but relies on eBay to supply his wafers. The video below is a longish intro to [Sam]’s methods, and his YouTube channel has a video tour of his fab and a few videos on making specific devices.

[Sam] credits [Jeri Ellsworth]’s DIY semiconductor efforts, which we’ve covered before, as inspiration for his fab, and we’re going to be watching to see where he takes it from here. For now, though, we’d better boost the aspiration level of our future projects.

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What the Flux: How Does Solder Work Anyway?

I’ve been soldering for a long time, and I take pride in my abilities. I won’t say that I’m the best solder-slinger around, but I’m pretty good at this essential shop skill — at least for through-hole and “traditional” soldering; I haven’t had much practice at SMD stuff yet. I’m confident that I could make a good, strong, stable joint that’s both electrically and mechanically sound in just about any kind of wire or conductor.

But like some many of us, I learned soldering as a practical skill; put solder and iron together, observe results, repeat the stuff that works and avoid the stuff that doesn’t. Seems like adding a little inside information might help me improve my skills, so I set about learning what’s going on mechanically and chemically inside a solder joint.

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Genetically Engineered Muscle Cells Power Tiny Bio-Robots

One of the essential problems of bio-robotics is actuators. The rotors, bearings, and electrical elements of the stepper motors and other electromechanical drives we generally turn to for robotics projects are not really happy in living systems. But building actuators the way nature does it — from muscle tissue — opens up a host of applications. That’s where this complete how-to guide on building and controlling muscle-powered machines comes in.

Coming out of the [Rashid Bashir] lab at the University of Illinois at Urbana-Campaign, the underlying principles are simple, which of course is the key to their power. The technique involves growing rings of muscle tissue in culture using 3D-printed hydrogel as forms. The grown muscle rings are fitted on another 3D-printed structure, this one a skeleton with stiff legs on a flexible backbone. Stretched over the legs like rubber bands, the muscle rings can be made to contract and move the little bots around.

Previous incarnations of this technique relied on cultured rat heart muscle cells, which contract rhythmically of their own accord. That yielded motion but lacked control, so for this go-around, [Bashir] et al used skeletal muscle cells genetically engineered to contract when exposed to light. Illuminating different parts of the muscle ring lets the researchers move the bio-bots anywhere they want. They can also use electric stimulation to control the bio-bots.

The method isn’t quite at the point where home lab biohackers will start churning out armies of bio-bots. But the paper is remarkably detailed in methods and materials, from the CAD files for 3D-printing the forms and bio-bot skeletons to a complete troubleshooting guide. It’s all there, and it could be a game changer for developing the robotic surgeons of the future.

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Down and Dirty with Contact Cleaners

I had a friend who was an engineer for a small TV station. I visited him at work once, and despite the fact that he wouldn’t let me climb the 1,200′ antenna tower, I had a great time. I was working for a video production studio at the time, so there was a fair amount in common about our jobs. One of the regular chores we faced was cleaning the heads on tape machines. He had a 5-gallon pail of cleaning solution under his bench that he told me was Freon, which he swore by for head cleaning and general contact cleaning. He gave me some for my shop in a little jar.

I never knew for sure if that stuff was Freon, but it was the mid-80s, shortly before CFCs were banned, so it might have been. All I know is that I’ve never found its equal for cleaning electronics gear. With that in mind, I thought I’d look at contact cleaners that are in use today, what’s really going on when you clean contacts, and why contacts even need cleaning in the first place.

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Explosive New Process Produces Graphene by the Gram

You say you need some graphene so you can invent the Next Big Thing, but you can’t be bothered with processes that yield a few measly milligrams of the precious stuff. Luckily for you there’s a new method for producing gram quantities of graphene. Perhaps unluckily, it requires building a controlled fuel-air bomb.

Graphene is all the rage today, promising to revolutionize everything from batteries to supercapacitors to semiconductors. A molecularly-2D surface with unique properties, graphene can be made in very small quantities with such tedious methods as pulling flakes of the stuff off graphite lumps with Scotch tape. Slightly less ad hoc methods involve lasers, microwaves, or high temperatures and nasty chemicals. But all of these methods are batch methods that produce vanishingly small amounts of the stuff.

The method [Chris Sorenson] et al of Kansas State University developed, which involves detonating acetylene and oxygen in a sturdy pressure vessel with a spark plug, can produce grams of graphene at a go. And what’s more, as their patent application makes clear, the method is amenable to a continuous production process using essentially an acetylene-fueled internal combustion engine.

While we can’t encourage our readers to build an acetylene bomb in the garage, the process is so simple that it would be easily replicated. We wonder how far down it could scale for safety and still produce graphene. Obviously, be careful if you choose to replicate this experiment. If you don’t like explosions and can source some soybean oil and nickel foil, maybe try this method instead. Then you’ll have something to mix with your Silly Putty.

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Living High-Altitude Balloon

High-altitude balloons are used to perform experiments in “near space” at 60,000-120,000 ft. (18000-36000m). However, conditions at such altitude are not particularly friendly and balloons have to compete with ultraviolet radiation, bad weather and the troubles of long distance communication. The trick is to send up a live entity to make repairs as needed. A group of students from Stanford University and Brown University repurposed nature in their solution. Enter Bioballoon: a living high-altitude research balloon.

Instead of using inorganic materials, the Stanford-Brown International Genetically Engineered Machine (iGEM) team designed microbes that grow the components required to build various tools and structures with the hope of making sustained space research feasible. Being made of living material, Bioballoon can be grown and re-grown with the same bacteria, lowering the cost of manufacturing and improving repeatability.

Bioballoon is engineered to be modular, with different strains of bacteria satisfying different requirements. One strain of bacteria has been modified to produce hydrogen in order to inflate the balloon while the balloon itself is made of a natural Kevlar-latex mix created by other cells. Additionally, the team is using Melanin, the molecule responsible for skin color and our personal UV protection to introduce native UV resistance into the balloon’s structure. And, while the team won’t be deploying a glider, they’ve designed biological thermometers and small molecule sensors that can be grown on the balloon’s surface. They don’t have any logging functionality yet, but these cellular hacks could amalgamate as a novel scientific instrument: cheap, light and durable.

Living things too organic for your taste? Don’t worry, we’ve got some balloons that won’t grow on you.

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