Watching The Global Oil Trade With Satellite Imagery

November 9, 2020 by Danie Conradie 10 Comments

The global oil market plays a large role in the geopolitical arena, and it is often in the interest of various role players to conceal the figures on production, consumption and movement of oil. This may simply to be to gain an advantage at the negotiation tables, or to skirt around international sanctions. The website [TankerTrackers] is in the business of uncovering these details, often from open source intelligence. Using satellite imagery, they are using a simple way to monitor the occupancy crude oil storage facilities around the world.

The key is in the construction of large capacity crude oil storage tanks. To prevent the flammable gasses emitted by crude oil from collecting inside partially empty tanks, they have roofs that physically float on top of the oil, moving up and down inside the steel sides as the levels change. By looking at imagery from the large number of commercial satellites that constantly photograph earth’s surface, one can determine how full the tanks are by comparing the length of a shadow inside the tank to the shadow outside the tank. Of course, you also need to know the diameter and height of a tank. Diameter is easy, just use Google Earth’s ruler tool. Height is a bit more tricky, but can often be determined by just checking the facilities’ website for ground level photos of the tanks. Of course these methods won’t give you exact numbers, but it’s good enough for rough estimates.

Another interesting detail we found perusing the [TankerTrackers] news posts (requires sign-up) is that tankers will sometimes purposefully switch off their AIS transponders, especially when heading to and from sanctioned countries such as Venezuela and Iran. Even in today’s world of omnipresent tracking technologies, it’s surprisingly easy for a massive ship to just disappear. Sometimes [TankerTrackers] will then use imagery to track down these vessels, often by just watching ports.

Thanks for the tip [Arpad Toth]!

Photo by [Terryjoyce] CC BY-SA 3.0

Hello From The NearSpace

November 9, 2020 by Matthew Carlson 6 Comments

A key challenge for any system headed up into the upper-atmosphere region sometimes called near space is communicating back down to the ground. The sensors and cameras onboard many high altitude balloons and satellites aren’t useful if the data they collect can’t be retrieved. Often times, custom antennas or beacons are added to help. Looking at the cost and difficulty of the problem, [arko] and [upaut] teamed up to try and make a turn-key solution for any near-space enthusiast by building CUBEX, a wonderful little module with sensors and clever radio that can be easily reused and repurposed.

CUBEX is meant as a payload for a high-altitude balloon with a camera, GPS, small battery, solar cell, and the accompanying power management circuits. The clever bit comes in the radio back down. By using the 434.460 Mhz band, it can broadcast around a hundred miles at 10mW. The only hardware to receive is a radio listener (a cheap RTL USB stick works nicely). Pictures and GPS coordinates stream down at 300 baud.

Their launch was quite successful and while they didn’t catch a solar eclipse, their balloon reached an impressive 33698m (110,560ft) while taking pictures. Even though it did eventually splashdown in the Pacific Ocean, they were able to enjoy a plethora of gorgeous photos thanks to their easy and cost-effective data link.

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Infinity Mirror Guitar Shreds Forever

November 9, 2020 by Kristina Panos 5 Comments

Just when we thought there was nothing left to make into an infinity mirror, [Burls Art] goes and builds something that seems obvious now that it exists — an infinity mirror guitar. Check out the build video after the break, where [Burls Art] gets right to it without wasting any time.

He started by making a 3/4″ wood frame for the body and the one-piece neck and headstock. The acrylic on the top has two-way mirror film, and the back piece is painted with mirror paint to get the infinity effect going. [Burls Art] also fashioned acrylic boxes for the pickup and the electronics. Those are both buffed to be frosty, so the lights reflect nicely off of them.

There’s nothing super-fancy going on with the electronics, just some app-controlled RGB LEDs. We would love to see a version where the LEDs respond in real time to the music. The effect is still quite cool, so if you don’t want to watch the whole build, at least check out the demo at the end where [Burls Art] plays a riff. Never has a delay pedal been so appropriate.

If you’re not much of a luthier, don’t fret about not being able to make a cover version. We’ve seen plenty of infinity mirrors, but if you want something useful, whip up some infinity drink coasters.

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Getting Over 4Gbps Out Of A Compute Module 4

November 9, 2020 by Lewin Day 30 Comments

For the average home gamer, good old fashioned Ethernet at 100 Mbit/s is only just starting to become a bottleneck as things like 4K video streaming begin to demand more bandwidth. As always, though, there are those who wish to push the limits of what is possible. [Jeff Geerling] is one such operator, who set out to maximise the network throughput on the Raspberry Pi Compute Module 4.

The build began by taking advantage of the PCI-Express 2.0 single lane interface on the new Raspberry Pi Compute Module. Hooked up to an Intel four-port Gigabit Ethernet card, and in combination with the onboard Gigabit-E port, [Jeff] was able to get 3.0 Gbit/s out of the setup without too much fuss. However, he wanted more, and set about finding where he was being held back. It turned out that ksoftirqd, a daemon that handles network packets, can only run on one core on the Raspberry Pi 4, and it was getting maxed out at this data rate. Overclocking the CPU helped, getting the max rate up to 3.4 Gbit/s.

Further analysis showed that the onboard interface was only contributing 200 Mbit/s, with the Intel card maxing out at 3.2 Gbit/s. In the case of the latter, this was due to the limits of the PCI-E interface. In the case of the former, however, [Jeff] knew that more was available. The trick turned out to be recompiling the Linux kernel to allow the internal interface to be able to set to use a higher Maximum Transmission Unit. This allows each network transmission to carry more data without extra CPU load. With the internal interface and the external card all set to an MTU of 9000, the Pi was able to spit out a scorching 4.15 Gbit/second. Details of the hack are available on Github for the curious.

It’s a hack that doesn’t offer a lot to the average user, though [Jeff] states he has some interesting applications in mind. He’s also contemplating what can be achieved with a 10 Gbit card, which we can’t wait to see. If you want to learn more about the Compute Module’s features, including a couple of tips for laying out yor own board, check out our review. Video after the break.

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Prism Lighting – The Art Of Steering Daylight

November 9, 2020 by Moritz v. Sivers 33 Comments

The incandescent light bulb was one of the first early applications of electricity, and it’s hard to underestimate its importance. But before the electric light, people didn’t live in darkness — they thought of ways to redirect sunlight to brighten up interior spaces. This was made possible through the understanding of the basic principles of optics and the work of skilled glassmakers who constructed prism tiles, deck prisms, and vault lights. These century-old techniques are still being applied today for the diffusion of LEDs or for increasing the brightness of LCD displays.

Semantics First!

People in optics are a bit sloppy when it comes to the definition of a prism. While many of them are certainly not geometric prisms, Wikipedia defines it as a transparent optical element with flat, polished surfaces of which at least one is angled. As can be seen in the pictures below some of the prisms here do not even stick to this definition. Browsing the catalog of your favorite optics supplier you will find a large variety of prisms used to reflect, invert, rotate, disperse, steer, and collimate light. It is important to point out that we are not so much interested in dispersive prisms that split a beam of white light into its spectrum of colors, although they make great album covers. The important property of prisms in this article is their ability to redirect light through refraction and reflection.

A Safe Way to Bring Light Under Deck

A collection of deck lights used to direct sunlight below deck in ships. Credit: glassian.org

One of the most important uses of prism lighting was on board ships. Open flames could have disastrous consequences aboard a wooden ship, so deck prisms were installed as a means to direct sunlight into the areas below decks. One of the first patents for deck lights “THE GREAT AND DURABLE INCREASE OF LIGHT BY EXTRAORDINARY GLASSES AND LAMPS” was filed by Edward Wyndus as early as 1684. Deck prisms had typical sizes of 10 to 15 centimeters. The flat top was installed flush with the deck and the sunlight was refracted and directed downward from the prism point. Because of the reversibility of light paths (“If I can see you, you can see me”) deck prisms also helped to spot fires under deck. Continue reading “Prism Lighting – The Art Of Steering Daylight” →

Learning SDR And DSP Hack Chat

November 9, 2020 by Dan Maloney No comments

Join us on Wednesday, November 11th at noon Pacific for Learning SDR and DSP Hack Chat with Marc Lichtman!

“Revolution” is a term thrown about with a lot less care than it probably should be, especially in fields like electronics. It’s understandable, though — the changes to society that have resulted from the “Transistor Revolution” or the “PC Revolution” or more recently, the “AI Revolution” have been transformative, often for good and sometimes for ill. The common thread, though, is that once these revolutions came about, nothing was ever the same afterward.

Such is the case with software-defined radio (SDR) and digital signal processing (DSP). These two related fields may not seem as transformative as some of the other electronic revolutions, but when you think about it, they really have transformed the world of radio communications. SDR means that complex radio transmitters and receivers, no longer have to be implemented strictly in hardware as a collection of filters, mixers, detectors, and amplifiers; instead, they can be reduced to a series of algorithms running on a computer.

Teamed with DSP, SDR has resulted in massive shifts in the RF field, with powerful, high-bandwidth radio links being built into devices almost as an afterthought. But the concepts can be difficult to wrap one’s head around, at least when digging beyond the basics and really trying to learn how SDR and DSP work. Thankfully, Dr. Marc Lichtman, an Adjunct Professor at the University of Maryland, literally wrote the book on the subject. “PySDR: A Guide to SDR and DSP using Python” is a fantastic introduction to SDR and DSP that’s geared toward those looking to learn how to put SDR and DSP to work in practical systems. Dr. Lichtman will stop by the Hack Chat to talk about his textbook, to answer your questions on how best to learn about SDR and DSP, and to discuss what the next steps are once you conquer the basics.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, November 11 at 12:00 PM Pacific time. If time zones baffle you as much as us, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

[Banner image credit: Dsimic, CC BY-SA 4.0, via Wikimedia Commons]

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The Logic Chip RISC-V Project Reboots

November 9, 2020 by Jenny List 15 Comments

The RISC-V architecture is inexorably inching from its theoretical origins towards the mainstream, as what could once only be done on an exotic FPGA can now be seen in a few microcontrollers as well as some much more powerful processors. It’s exciting because it offers us the prospect of fully open-source hardware on which to run our open-source operating systems, but it’s more than that. RISC-V isn’t a particular processor core so much as a specification that can be implemented at any of a number of levels, and in its simplest form can even be made real using 74 logic chips. This was the aim of [Robert Baruch]’s LMARV-1 that caused a stir a year or two ago but then went on something of a hiatus. We’re pleased to note that he’s posted a video announcing a recommencement of the project, along with a significant redesign.

We’ve placed the video below the break, and it’s much more than a simple project announcement. Instead, it’s an in-depth explanation of the design decisions and the physical architecture of the processor. It amounts to a primer on processor design, and though it’s a long watch we’d say you won’t be disappointed if your interests lie in that direction.

We first covered the LMARV-1 back in early 2018, so we’re glad to see it back in progress and we look forward to seeing its continued progress.

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