Eye-Tracking Device Is A Tiny Movie Theatre For Jumping Spiders

October 28, 2021 by Donald Papp 18 Comments

The eyes are windows into the mind, and this research into what jumping spiders look at and why required a clever device that performs eye tracking, but for jumping spiders. The eyesight of these fascinating creatures in some ways has a lot in common with humans. We both perceive a wide-angle region of lower visual fidelity, but are capable of directing our attention to areas of interest within that to see greater detail. Researchers have been able to perform eye-tracking on jumping spiders, literally showing exactly where they are looking in real-time, with the help of a custom device that works a little bit like a miniature movie theatre.

A harmless temporary adhesive on top (and a foam ball for a perch) holds a spider in front of a micro movie projector and IR camera. Spiders were not harmed in the research.

To do this, researchers had to get clever. The unblinking lenses of a spider’s two front-facing primary eyes do not move. Instead, to look at different things, the cone-shaped inside of the eye is shifted around by muscles. This effectively pulls the retina around to point towards different areas of interest. Spiders, whose primary eyes have boomerang-shaped retinas, have an X-shaped region of higher-resolution vision that the spider directs as needed.

So how does the spider eye tracker work? The spider perches on a tiny foam ball and is attached — the help of a harmless and temporary adhesive based on beeswax — to a small bristle. In this way, the spider is held stably in front of a video screen without otherwise being restrained. The spider is shown home movies while an IR camera picks up the reflection of IR off the retinas inside the spider’s two primary eyes. By superimposing the IR reflection onto the displayed video, it becomes possible to literally see exactly where the spider is looking at any given moment. This is similar in some ways to how eye tracking is done for humans, which also uses IR, but watches the position of the pupil.

In the short video embedded below, if you look closely you can see the two retinas make an X-shape of a faintly lighter color than the rest of the background. Watch the spider find and focus on the silhouette of a tasty cricket, but when a dark oval appears and grows larger (as it would look if it were getting closer) the spider’s gaze quickly snaps over to the potential threat.

Feel a need to know more about jumping spiders? This eye-tracking research was featured as part of a larger Science News article highlighting the deep sensory spectrum these fascinating creatures inhabit, most of which is completely inaccessible to humans.

Continue reading “Eye-Tracking Device Is A Tiny Movie Theatre For Jumping Spiders” →

Keith Thorne, Engineer At LIGO, To Deliver Remoticon Keynote

October 11, 2021 by Mike Szczys 13 Comments

It is my pleasure to announce that Keith Thorne has graciously agreed to deliver a keynote take at Hackaday Remoticon 2. Get your ticket now!

Keith is an astrophysicist and has worked on the Laser Interferometer Gravitational-Wave Observatory (LIGO) since 2008, literally looking for ripples in space-time that you know as gravitational waves. The effects of the phenomena are so subtle that detecting an event requires planet-scale sensors in the form of 4 km long interferometers placed in different parts of the United States whose readings can be compared against one another. A laser beam inside these interferometers bounces back and forth 300 times for a total travel distance of 1,200 km in which any interaction with gravitational waves will ever-so-slightly alter how the photons from the beam register.

The challenges of building, operating, and interpreting such a device are manifold. These interferometers are the highest precision devices ever devised, able to detect motion 1/10,000 of the diameter of a proton! To get there, the mirrors need to be cooled to 77 nano-Kelvins. Getting the most out of it is what Keith and the rest of the team specialize in. This has included things like hacking the Linux kernel to achieve a sufficient level of real-time digital control, and using “squeezed light” to improve detection sensitivity in frequencies where quantum mechanics is getting in the way. While the detectors were first run in 2015 & 2016, successfully observing three events, the work to better understand this phenomenon is ongoing and may include a third site in India, and a space-based detector in the future.

In getting to know Keith he mentioned that he is excited to speak to a conference packed with people who want to hear the gory technical details of this fantastic piece of hardware. I’m sure we’re all giddy to learn what he has to say. But if you’re someone who wants to work on a project like this, he tipped us off that there’s an active EE job posting for LIGO right now. Maybe you’ll end up doing the keynote at a future Hackaday conference.

Call for Proposals is Still Open!

We’re still on the hunt for great talks about hardware creation. True creativity is fed by a steady stream of inspiration. Be that inspiration by giving a talk about the kinds of things you’ve been working on!

Japanese Rocket Engine Explodes: Continuously And On Purpose

September 2, 2021 by Lewin Day 62 Comments

Liquid-fuelled rocket engine design has largely followed a simple template since the development of the German V-2 rocket in the middle of World War 2. Propellant and oxidizer are mixed in a combustion chamber, creating a mixture of hot gases at high pressure that very much wish to leave out the back of the rocket, generating thrust.

However, the Japan Aerospace Exploration Agency (JAXA) has recently completed a successful test of a different type of rocket, known as a rotating detonation engine. The engine relies on an entirely different method of combustion, with the aim to produce more thrust from less fuel. We’ll dive into how it works, and how the Japanese test bodes for the future of this technology.

Deflagration vs. Detonation

Humans love combusting fuels in order to do useful work. Thus far in our history, whether we look at steam engines, gasoline engines, or even rocket engines, all these technologies have had one thing in common: they all rely on fuel that burns in a deflagration. It’s the easily controlled manner of slow combustion that we’re all familiar with since we started sitting around campfires. Continue reading “Japanese Rocket Engine Explodes: Continuously And On Purpose” →

Phased Array Levitation Is Science In Action

August 18, 2021 by Lewin Day 8 Comments

Levitation may seem like magic. However, for certain objects, and in certain conditions, it’s actually a solved technology. If you want to move small particles around or do experiments with ultrasonic haptic feedback, you might find SonicSurface to be a useful platform for experimentation.

The build comes to us from [UpnaLab], and is no small feat of engineering. It packs in 256 ultrasonic emitters in a 16×16 grid, with individual phase control across the entire panel. This allows for the generation of complex ultrasonic wave fields over the SonicSurface board. Two boards can be paired together in a vertically opposed configuration, too. This allows the levitation of tiny particles in 3D space.

As you might expect, an FPGA is pressed into service to handle the heavy lifting – in this case, an Altera CoreEP4CE6. Commands are sent to the SonicSurface by a USB-to-serial connection from an attached PC.

The board is largely limited to the levitation of small spherical pieces of foam, with the ultrasonic field levitating them in midair. However, the project video shows how these tiny pieces of foam can be attached to threads, tapes, and other objects in order to manipulate them with the ultrasonic array.

It may not be a simple project, but it serves as a great basis for your own levitation experiments. Of course, if you want to start smaller, that’s fine too. If you come up with any great levitation breakthroughs of your own, be sure to let us know.

Solving Ultra High Vacuum Leaks Has An Elementary Solution

August 16, 2021 by Ryan Flowers 34 Comments

When we think of a vacuum leak we generally think of a car that just doesn’t want to run quite right. Most normally aspirated internal combustion engines rely on the vacuum created by the pistons to draw in the air fuel mixture that’s produced by the carburetor or fuel injection system. Identifying the leak usually involves spraying something combustible around common trouble areas while the engine is running. Changes to the engine speed indicate when the combustible gas enters the intake manifold and the leak can be found.

What if your vacuum leak is in a highly specialized piece of scientific equipment where the pressures are about 12 ~~times~~ orders of magnitude lower than atmospheric pressure, and the leak is so small it’s only letting a few atoms into the vacuum chamber at a time? [AlphaPhoenix] takes dives deep into this very subject in his video “Air-tight vs. Vacuum-tight.” which you can watch below the break.

Not only does [AlphaPhoenix] discuss how a perfect pressure vessel is sealed, he also explains the specialized troubleshooting methods used which turn out not to be all that different from troubleshooting an automotive vacuum leak- only in this case, several magnitudes more complex and elemental in nature.

We also enjoyed the comments section, where [AlphaPhoenix] addresses some of the most common questions surrounding the video: Torque patterns, the scarcity of the gasses used, and leaving well enough alone.

Does talking about vacuums get you pumped? Perhaps you’d enjoy such vacuum hacks as putting the toothpaste back in the tube in your homemade vacuum chamber.

Thank you [Morgan] for sending this one in. Be sure to send in your own hacks, projects, and fantastic finds through the Tip Line!

Continue reading “Solving Ultra High Vacuum Leaks Has An Elementary Solution” →

Affordable Transilluminator Helps Visualize DNA

May 22, 2021 by Al Williams 2 Comments

If you want to examine the results of gel electrophoresis — and who doesn’t — you need a transilluminator. These devices can be quite pricey, though, so you might want to check out [Gabriel St-Pierre’s] plans to make an affordable blue-light version. You can see a video about the device below.

Using a UV filter, an Arduino Nano, an LED strip, 3D printing, and some mechanical items, it looks like this is a very easy project if you need such a device. There are a few miscellaneous parts like a hinge and some mirror material, but nothing looks too exotic.

Continue reading “Affordable Transilluminator Helps Visualize DNA” →

Something’s Up In Switzerland: Explaining The B Meson News From The Large Hadron Collider

May 13, 2021 by Bob Baddeley 50 Comments

Particle physics is a field of extremes. Scales always have 10^{really big number} associated. Some results from the Large Hadron Collider Beauty (LHCb) experiment have recently been reported that are statistically significant, and they may have profound implications for the Standard Model, but it might also just be a numbers anomaly, and we won’t get to find out for a while. Let’s dive into the basics of quantum particles, in case your elementary school education is a little rusty.

It all starts when one particle loves another particle very much and they are attracted to each other, but then things move too fast, and all of a sudden they’re going in circles in opposite directions, and then they break up catastrophically…

Continue reading “Something’s Up In Switzerland: Explaining The B Meson News From The Large Hadron Collider” →