We’re always on the lookout for unexpected budget builds here at Hackaday, and stumbling across a low-cost, DIY version of an instrument that sells for tens of thousands of dollars is always a treat. And so when we saw a tip for a homebrew gas chromatograph in the tips line this morning, we jumped on it. (Video embedded below.)
For those who haven’t had the pleasure, gas chromatography is a chemical analytical method that’s capable of breaking a volatile sample up into its component parts. Like all chromatographic methods, it uses an immobile matrix to differentially retard the flow of a mobile phase containing the sample under study, such that measurement of the transit time through the system can be made and information about the physical properties of the sample inferred.
The gas chromatograph that [Chromatogiraffery] built uses a long stainless steel tube filled with finely ground bentonite clay, commonly known as kitty litter, as the immobile phase. A volatile sample is injected along with an inert carrier gas – helium from a party balloon tank, in this case – and transported along the kitty litter column by gas pressure. The sample interacts with the column as it moves along, with larger species held back while smaller ones speed along. Detection is performed with thermal conductivity cells that use old incandescent pilot lamps that have been cracked open to expose their filaments to the stream of gas; using a Wheatstone bridge and a differential amp, thermal differences between the pure carrier gas and the eluate from the column are read and plotted by an Arduino.
The homebrew GC works surprisingly well, and we can’t wait for [Chromatogiraffery] to put out more details of his build.
When we first heard about this, courtesy in part via a Hackaday post on MRI-killed iPhones, we couldn’t imagine how poisoning a micro-electromechanical system (MEMS) part could kill a phone. We’d always associated MEMS with accelerometers and gyros, important sensors in the smartphone suite, but hardly essential. It turns out there’s another MEMS component in many Apple products: an SiT 1532 oscillator, a tiny replacement for quartz crystal oscillators.
[Ben] got a few from DigiKey and put them through some tests in a DIY gas chamber. He found that a partial pressure of helium as low as 2 kPa, or just 2% of atmospheric pressure, can kill the oscillator. To understand why, and because [Ben] has a scanning electron microscope, he lapped down some spare MEMS oscillators to expose their intricate innards. His SEM images are stunning but perplexing, raising questions about how such things could be made which he also addresses.
The bottom line: helium poisons MEMS oscillators in low enough concentrations that the original MRI story is plausible. As a bonus, we now understand MEMS devices a bit better, and have one more reason never to own an iPhone.
Sometimes hacking isn’t as much about building something, it’s about getting to the root of a particularly difficult problem. [Erik Wooldrige] was facing a problem like that. He’s a system specialist at a hospital near Chicago. Suddenly a bunch of iPhones and Apple watches were failing or glitching. The only thing anyone could think of was the recent install of an MRI machine.
Sure, an MRI machine can put out some serious electromagnetic pulses, but why would that only affect Apple products? Everything else in the hospital, including Android phones, seemed to be OK. But about 40 Apple devices were either dead or misbehaving.
That’s what [IzzyBrand] and his cohorts did, and we have to say we’re mightily impressed. The glider itself looks like nothing to write home about: in true Flite Test fashion, it’s just a flying wing made with foam core and Coroplast reinforced with duct tape. A pair of servo-controlled elevons lies on the trailing edge of the wings, while inside the fuselage are a Raspberry Pi and a Pixhawk flight controller along with a GPS receiver. Cameras point fore and aft, a pair of 5200 mAh batteries provide the juice, and handwarmers stuffed into the avionics bay prevent freezing.
After a long series of test releases from a quadcopter, flight day finally came. Winds aloft prevented a full 30-kilometer release, so the glider was set free at 10 kilometers. The glider then proceeded to a pre-programmed landing zone over 80 kilometers from the release point. At one point the winds were literally pushing the glider backward, but the little plane prevailed and eventually spiraled down to a perfect landing.
We’ve been covering space balloons for a while, but take a moment to consider the accomplishment presented here. On a shoestring budget, a team of amateurs hit a target the size of two soccer fields with an autonomous aircraft from a range of almost 200 kilometers. That’s why we’re impressed, and we can’t wait to see what they can do after a release from the edge of space.
Ever since I first learned about radiosondes as a kid, I’ve been fascinated by them. To my young mind, the idea that weather bureaus around the world would routinely loft instrument-laden packages high into the atmosphere to measure temperature, pressure, and winds aloft seemed extravagant. And the idea that this telemetry package, having traveled halfway or more to space, could crash land in a field near my house so that I could recover it and take it apart, was an intoxicating thought.
I’ve spent a lot of time in the woods over the intervening years, but I’ve never seen a radiosonde in the wild. The closest I ever came was finding a balloon with a note saying it had been released by a bunch of schoolkids in Indiana. I was in Connecticut at the time, so that was pretty cool, but those shortsighted kids hadn’t put any electronics on their balloon, and they kind of left me hanging. So here’s a look at what radiosondes are, how they work, and what you can do to increase your chances of finding one.
There was a time when you could do what you wanted in your yard and hams could build giant antenna farms. These days, there are usually laws or deed restrictions that stop that from happening. Even if you can build an antenna, you might want to quickly put up something temporary in an emergency.
[Eric’s] solution? Suspend a wire from a weather balloon filled with helium from the local WalMart. The 8 foot balloon took two containers (18 cubic feet) of gas before it would rise sufficiently. Once you have a floating balloon, the rest of the concept is simple: connect a wire (100 feet of 26 gauge), use a tuner to match the load to the transmitter, and you have instant antenna.
If you’ve been reading the news lately, you doubtless read about the find of a really big new helium gas field in Tanzania. It’s being touted as “life-saving” and “game-changing” in the popular media, but this is all spin. Helium is important for balloon animals, scientists, and MRI machines alike, but while it’s certainly true that helium prices have been rising steadily since 2000, this new field is unlikely to matter all that much in the grand scheme of things.
The foundation of every news story on helium is that we’re running out of the stuff. As with most doomsday scenarios, the end of the world’s supply of helium is overstated, and we don’t just mean in light of the new Tanzanian field. Helium is the second-most abundant element, making up 24% of the total mass of the universe. And while the earth has a disproportionate amount of heavier elements, helium is in rocks everywhere. It’s just a question of getting it out, and at what price that’s viable.
So while we’re stoked that the era of (relatively) cheap helium can continue onwards for a few more years, we’re still pretty certain that the price is going to continue to rise, and our children’s children won’t be using the stuff for something so frivolous as blowing up party balloons — it’ll be used primarily, as it is now, where it’s more valuable: in science, medicine, and industry.
Let’s take this moment to reflect on the economics of second-lightest element. Here’s to you, Helium!