There is a romance to notions of a byegone age of DJing — driving a pair of Technics 1200s dwarfed on either side by the stacks, pumping techno bass through the laser-tinged darkness into a hungry crowd. Even if the reality of early evening Saturday wedding parties playing inoffensive crooners for the 50-somethings didn’t really live up to it.
The trouble with DJing old-style was that it required extensive logistics to shift all that equipment not to mention a record collection, so the modern DJ for whom everything has gone digital is truly lucky in the scale of their operation. For some people even that is too much to carry, and [Dennisdebel] has minimised a DJ rig to the next level, by running the popular Mixxx DJing software on a Raspberry Pi hooked up to his DJ controller. You can see the result in the video below the break.
This is more of a HOWTO for installing a set of software packages on the Pi to achieve an aim rather than a special hardware hack, but as he points out the interest lies in regaining control of the process. The DJ space is dominated by commercial offerings increasingly laden with DRM and proprietary cloud offerings, so this represents a means of taking back control of the process. If it’s not hacky enough, you can always add a home-made DJ mixing station.
Another couple of weeks, and a fresh crop of space news to run through as a quick briefing of the latest in the skies above us.
OneWeb’s most recent launch, from Baikonur on the 21st of March 2020. (OneWeb)
The global positioning orbits are getting pretty crowded, with GPS, Russia’s GLONASS, the EU’s Galileo, Japan’s QZSS, and now with the launch of the final satellite in their constellation, China’s BeiDou. As if five were not enough the chance that they might be joined by a sixth constellation from the United Kingdom resurfaced this week, as the UK government is expressing interest in supporting a rescue package for the troubled satellite broadband provider OneWeb. The idea of an independent GPS competitor from a post-Brexit UK has been bouncing around for a couple of years now, and on the face of it until this opportune chance to purchase an “oven ready” satellite constellation might deliver a route to incorporating a positioning payload into their design. The Guardian has its doubts, lining up a bevvy of scientists to point out the rather obvious fact that a low-earth-orbit satellite broadband platform is a very different prospect to a much-higher-orbiting global positioning platform. Despite the country possessing the expertise through its work on Galileo then it remains to be seen whether a OneWeb purchase would be a stroke of genius or a white elephant. Readers with long memories will know that British government investment in space has had its upsets before.
Happily for Brits, not all space endeavours from their islands end in ignominious retreat. Skyrora have scored another milestone, launching the first ever rocket skywards from the Shetland Islands. The Skylark Nano is a relatively tiny craft at only 2m high, and gathered research data during its flight to an altitude of 6km. We’ve followed their work before, including their testing in May of a Skylark L rocket on the Scottish mainland with a view to achieving launch capability in 2023.
A Starlink phased array end user antenna, spotted in Winsconsin. (darkpenguin22)
SpaceX’s Starlink is never far away from the news, with a fresh set of launches delayed for extra pre-launch tests, and the prospect of signing up to be considered for the space broadband firm’s beta test. Of more interest for Hackaday readers though are a few shots of prototype Starlink ground stations and user terminals that have made it online, on the roof of a Tesla Gigafactory and at a SpaceX facility in Wisconsin. What can be seen are roughly 1.5m radomes for the ground stations and much smaller dinner-plate-sized enclosed arrays for the user terminals. The latter are particularly fascinating as they conceal computer-controlled phased arrays for tracking the constellation as it passes overhead. This is a technology more at home in billion-dollar military radars than consumer devices, so getting it to work on a budget that can put it on a roof anywhere in the world must be a challenge for the Starlink engineers. We can’t wait to see the inevitable eventual teardown when it comes.
Elsewhere, the Virgin Galactic SpaceShip Two completed its second glide test over its Mojave Spaceport home since being grounded in 2019 for extensive refitting, and is now said to be ready for powered tests leading to eventual commercial service giving the extremely well-heeled the chance to float in the zero gravity of suborbital spaceflight. And finally, comes the news that NASA are naming their Washington DC headquarters building for Mary W. Jackson, their first African American female engineer, whose story some of you may be familiar with from the book and film Hidden Figures. The previously unnamed building sits on a section of street named Hidden Figures Way.
If you spent your youth watching James Bond or similar movies on rainy Saturday afternoons, then you may be familiar with a microdot as a top-secret piece of spy equipment, usually revealed as having been found attached to a seemingly innocuous possession of one of the bad guy’s henchmen, which when blown up on the screen delivers the cryptic yet vital clue to the location of the Evil Lair. Not something you give much thought in 2020 you might think, but that’s reckoning without [Sister HxA], who has worked out how to make them herself and detailed the process in a Twitter thread.
A microdot is a tiny scrap of photographic film, containing the image of some secret document or other, the idea being that it is small enough to conceal on something else. The example she gives is hiding it underneath a postage stamp. Because of their origins in clandestine work there is frustratingly little info on how to produce them, but she found a set of British instructions. Photographing a sheet such that its image occupies a small portion of her negative she makes a postage-stamp-sized one, and with care photographing that she manages to produce another of only a few millimetres in size. The smaller one isn’t very legible, but it’s still a fascinating process.
In the matter of technological advancement, we are as a species, mostly insatiable. The latest toy, the fastest silicon, the largest storage, the list goes on. Take digital cameras as an example, what was your first one? Mine was a Casio QV200 in about 1997, I still have it somewhere though I can’t immediately lay my hands on it, and it could hold a what was for its time a whopping 64 VGA-resolution pictures in its 4Mb of onboard memory.
The QV200 showing off its VGA photography capabilities. It’s March 1998, and this is a brand-new PlayStation that I’m about to install a mod chip inside.
It’s a shock to realise that nearly a quarter century has passed since then, and its fixed-focus 640×480 camera module with a UV-sensitive CMOS sensor that gave everything a slight blue tint would not even grace the cheapest of feature phones in 2020. Every aspect of a digital camera has improved beyond measure since the first models in the 1980s and early 1990s that started to resemble what we’d know today as a standalone digital camera, they have near-limitless storage, excellent lenses, huge and faithfully-reproducing sensors, and broadcast-quality video capability.
But how playful have camera manufacturers been with the form factor? We see reporters in sci-fi movies toting cameras that look nothing like their film-based ancestors. What do our real-life digital cameras have on offer as far as creative body design goes?
If you’ve got a few self-designed PCBs under your belt, you probably know the pain of missing some little detail and having to break out the bodge wires to fix it. So we feel for [Arsenio Dev], who placed an SD card slot next to an SoC, only to find that it was the wrong way round. Rather than tossing it in the bin, he decided to employ a particularly crafty set of bodge wires that curve over the board and connect to an SD card adapter on the other side.
Our attention was taken by the board itself, he’s posted little information about it and taken pains to conceal one of the pieces of text on it. Since it has an Octavo Systems BeagleBone-on-chip, a slot for a cellular modem, and a connector marked “CONNECT AERONET HERE” which we are guessing refers to the Aeronet sun photometry network, we’re guessing it might be a controller for remotely-sited nodes for that system. Either way it’s enough to have us intrigued, and we wish him every success with the next spin.
The term “vacuum” means many different things depending whether you are working on space equipment, scientific instruments, or even internal combustion engines. In our sphere it is so often used as a means to draw bubbles out of resin castings, for which it is a relatively easily achievable partial vacuum. It’s something [Fab] is using, in a vacuum chamber made from Plexiglass.
A simple Plexiglass box would collapse under the air pressure on its own, so to mitigate that it’s made from a piece of tube, and with an internal frame of aluminium extrusion with 3D printed joints to strengthen it from the inside. A pressure sensor allows regulation of the pump that drives the vacuum, and connections are made to the chamber using pneumatic hose connectors. It’s not immediately clear how it is sealed, whether there are nay gaskets or other sealant, or whether air pressure pushing the parts together provides enough of a seal.
We’ve featured a lot of vacuum chambers made for this purpose over the years, and we’d be interested to know what vacuum pump is being used here. If you’re curious too and want to build your own, perhaps you could try a fridge compressor.
On some 2011 Macbook Pro models, there is a tendency for the Radeon GPU to fail. This should mean game over for the computer, but surprisingly salvation is offered by its having not one but two GPUs on board. The Intel processor also has a GPU, and Apple use a pile of logic in an FPGA to switch at will between them. The community have produced fresh FPGA code to revive a dead Mac on its Intel GPU, but at the expense of losing brightness control. [Ayilm1] has brought back the brightness with a clever BGA reworking hack that gains access to a brightness control line present on the Intel BD82HM65 Platform Controller Hub chip but not used in the Macbook.
We’re used to impressive soldering work here at Hackaday, and we’ve seen our share of wiring direct to the balls on an upturned BGA chip. This is a similar idea but at another level, as a section of the top insulation on an in-place BGA is removed to expose the microvia above the ball carrying the required signal. A tiny wire is soldered to the exposed pad and taken to a piece of copper tape stuck down to provide mechanical strength, and a piece of enameled copper wire is run from that to the other side of the PCB where lies its destination. It comes with FPGA code to take advantage of it, but even for non-Macbook owners, it’s an extremely impressive piece of work. It’s not the first fine-soldering Macbook fix we’ve seen, either.
