How The LIGO Observatory Detects Gravitational Waves

Gravity is one of the more obvious forces in the universe, generally regarded as easily noticeable by the way apples fall from trees. However, the underlying mechanisms behind gravity are inordinately complex, and the subject of much study to this day.

A major component of this study is around the concept of gravitational waves. First posited by Henri Poincaré in 1905, and later a major component of Einstein’s general theory of relativity, they’re a phenomena hunted for by generations of physicists ever since. For the team at the Laser Interferometer Gravitational-wave Observatory, or LIGO, finding direct evidence of gravitational waves is all in a day’s work.

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Hacking The Ortur Laser With Spoil Board, Z-Height, And Air Assist

Last month in my hands-on review of the Ortur Laser I hinted that I had done a few things to make it work a little better. I made three significant changes in particular: I anchored the machine to a spoil board with markings, I added a moving Z axis to adjust focus by moving the entire laser head, and I added an air assist.

Turns out, you can find designs for all of these things all over the Internet and I did, in fact, use other people’s designs. The problem is the designs often conflict with one another or don’t exactly work for your setup. So what I’ll tell you about is the combination that worked for me and what I had to do to get it all working together. The air assist is going to take a post all by itself, but some of the attempts at air assist led to some of the other changes I made, so we’ll talk about it some in this post, as well.

One of the modifications — the spoil board mount — I simply downloaded and the link for that is below. However, I modified the moving Z axis and air assist parts and you can find my very simple modifications on Thingiverse. You’ll also find links to the original designs and you’ll need them for extra parts and instructions, too.

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Hey Google, Is My Heart Still Beating?

University of Washington researchers studying the potential medical use of smart speakers such as Amazon’s Echo and Google’s Nest have recently released a paper detailing their experiments with non-contact acoustic heartbeat detection. Thanks to their sensitive microphone arrays, normally used to help localize voice commands from the user, the team proposes these affordable and increasingly popular smart home gadgets could lead a double life as unobtrusive life sign monitors. The paper goes so far as to say that even with multiple people in the room, their technique can be used to monitor the heart and respiratory rate of a specific target individual.

Those are some bold claims, but they aren’t without precedent. Previous studies performed at UW in 2019 demonstrated how smart speaker technology could be used to detect cardiac arrest and monitor infant breathing. This latest paper could be seen as the culmination of those earlier experiments: a single piece of software that could not just monitor the vitals of nearby patients, but actually detect a medical emergency. The lifesaving potential of such a program, especially for the very young and elderly, would be incredible.

So when will you be able to install a heart monitor skill on the cheap Echo Dot you picked up on Prime Day? Well, as is often the case with this kind of research, putting the technique to work in the real-world isn’t nearly as easy as in the laboratory. While the concept is promising and is more than worthy of further research, it may be some time before our lowly smart speakers are capable of Star Trek style life-sign detection.

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A Lockdown Brightened By A Library Of Vintage Usborne Books

Lockdown is boring. No, let’s emphasize that, lockdown is really boring. Walking for exercise is much less fun than it was last year because it’s a wet and muddy February, and with nowhere open, a rare trip out to a McDonalds drive-through becomes a major outing. Stuck inside for the duration we turn our eyes to some of the older ways to wile away the time. Books. Remember them? In doing that I found that the friend whose house I’m living in has the whole library of Usborne children’s computer and technology books from the 1980s. Suddenly a rainy day doesn’t matter, because we’re in a cheerful world of cartoon robots and computer parts!

When Kids Learned Machine Code

A comprehensive selection to get one's teeth into.
A comprehensive selection to get one’s teeth into.

If this leaves you none the wiser, it’s worth explaining that during the 1980s home computer boom there was no Internet handily placed for finding out how your new toy worked. Instead you had to read books and hoard the scraps of information they contained. Publishers responded to this new world of technology with enthusiasm, and the British children’s publisher Usborne did so in their characteristic entertaining and informative style. For probably the only time in history, children were presented with mainstream books telling them how to write machine code and interface directly to microprocessors, and those among them who probably now read Hackaday took to them with glee. They remain something of a cult object among retrocomputing enthusiasts, and fortunately a selection of them are available for download. Usborne are still very much in business producing up-to-date books educating today’s children, and to promote some of their more recent titles for the Raspberry Pi they’ve released them in electronic form. Continue reading “A Lockdown Brightened By A Library Of Vintage Usborne Books” →

How Laser Headlights Work

When we think about the onward march of automotive technology, headlights aren’t usually the first thing that come to mind. Engines, fuel efficiency, and the switch to electric power are all more front of mind. However, that doesn’t mean there aren’t thousands of engineers around the world working to improve the state of the art in automotive lighting day in, day out.

Sealed beam headlights gave way to more modern designs once regulations loosened up, while bulbs moved from simple halogens to xenon HIDs and, more recently, LEDs. Now, a new technology is on the scene, with lasers!

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New Part Day: Onion Tau LiDAR Camera

The Onion Tau LiDAR Camera is a small, time-of-flight (ToF) based depth-sensing camera that looks and works a little like a USB webcam, but with  a really big difference: frames from the Tau include 160 x 60 “pixels” of depth information as well as greyscale. This data is easily accessed via a Python API, and example scripts make it easy to get up and running quickly. The goal is to be an affordable and easy to use option for projects that could benefit from depth sensing.

When the Tau was announced on Crowd Supply, I immediately placed a pre-order for about $180. Since then, the folks at Onion were kind enough to send me a pre-production unit, and I’ve been playing around with the device to get an idea of how it acts, and to build an idea of what kind of projects it would be a good fit for. Here is what I’ve learned so far.

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Science Officer…Scan For Elephants!

If you watch many espionage or terrorism movies set in the present day, there’s usually a scene where some government employee enhances a satellite image to show a clear picture of the main villain’s face. Do modern spy satellites have that kind of resolution? We don’t know, and if we did we couldn’t tell you anyway. But we do know that even with unclassified resolution, scientists are using satellite imagery and machine learning to count things like elephant populations.

When you think about it, it is a hard problem to count wildlife populations in their habitat. First, if you go in person you disturb the target animals. Even a drone is probably going to upset timid wildlife. Then there is the problem with trying to cover a large area and figuring out if the elephant you see today is the same one as one you saw yesterday. If you guess wrong you will either undercount or overcount.

The Oxford scientists counting elephants used the Worldview-3 satellite. It collects up to 680,000 square kilometers every day. You aren’t disturbing any of the observed creatures, and since each shot covers a huge swath of territory, your problem of double counting all but vanishes.

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