Running A Modern Graphics Card In A 33 MHz PCI Slot

July 26, 2023 by 21 Comments

If you ever looked at a PCI to PCIe x16 adapter and wondered what’d happen if you were to stick a modern PCIe GPU in it, the answer apparently is ‘it works’ according to an attempt by [Circuit Rewind]. As long as you accept needing to supply external power with even a low-end GT 1030 card – as the PCI slot cannot provide enough power – and being limited to a single PCIe lane. This latter point isn’t so much of an issue as a single PCIe lane offers more bandwidth than the (shared) PCI bus anyway.

Despite the somewhat improvised setup, the GT 1030 card provided a decent 1080p experience in a range of games, after removing half of the 8 GB of system RAM before the configuration would work, probably due to VRAM mapping issues. Since the mainboard used also offered PCIe, the same card was run in a PCIe x4 slot, as well as in an x1 configuration, both with noticeably higher performance and putting the ‘why’ in ‘try’.

Perhaps unsurprisingly, a RTX 3080 also booted fine with external power and only 4 GB system RAM installed. Despite the PCIe x1 link, the system was able to finish a 3D benchmark and play Doom 2016, but with only 4 GB of system RAM and an old Athlon quad-core CPU, it was a terrible experience. Perhaps the most fascinating lesson to learn from this is that PCI and PCIe are amazingly compatible with only a simple translation bridge, even if high-performance graphics aren’t quite what PCI was meant for. After all, that’s why we got cursed with AGP for many years.

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3D-Printed RC Skid Steer Is Cute Construction Machinery Done Right

July 26, 2023 by 11 Comments

Skid steers are great fun if you get to drive one on a construction site. [ProfessorBoots] has long been a fan of the diminutive diggers, and decided to make a 3D-printed version for his own pleasure.

The build uses a chassis printed in several colors which adequately recreates the charms of a full-sized skid steer. The brains of the operation is an ESP32, which receives commands over WiFi for remote control. A pair of geared N20 brushed motors are driven from a small H-bridge controller, each one driving one side of the skid steer. A toothed belt was 3D printed to allow each motor to drive two wheels on one side. Meanwhile, a pair of servos are charged with both lifting and tilting the bucket. Yes, you heard correctly – you can actually pick up and carry objects around your desk with this thing.

It’s a neat build and could be your introduction into the world of RC construction machines. Video after the break.

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PCIe For Hackers: Our M.2 Card Is Done

July 25, 2023 by 16 Comments

We’ve started designing a PCIe card last week, an adapter from M.2 E-key to E-key, that adds an extra link to the E-key slot it carries – useful for fully utilizing a few rare but fancy E-key cards. By now, the schematic is done, the component placement has been figured out, and we only need to route the differential pairs – should be simple, right? Buckle up.

Getting Diffpairs Done

PCIe needs TX pairs connected to RX on another end, like UART – and this is non-negotiable. Connectors will use host-side naming, and vice-versa. As the diagram demonstrates, we connect the socket’s TX to chip’s RX and vice-versa; if we ever get confused, the laptop schematic is there to help us make things clear. To sum up, we only need to flip the names on the link coming to the PCIe switch, since the PCIe switch acts as a device on the card; the two links from the switch go to the E-key socket, and for that socket’s purposes, the PCIe switch acts as a host.

While initially routing this board, I absolutely forgot about one more important thing for PCIe – series capacitors on every data pair, on the host TX side of the link. We need three capacitor pairs here – on TX of the PCIe switch uplink, and two pairs on TX side of the switch – again, naming is host-side. I only remembered this after having finished routing all the diffpairs, and, after a bit of deliberation, I decided that this is my chance to try 0201 capacitors. For that, I took the footprints from [Christoph]‘s wonderful project, called “Effect of moon phase on tombstoning” – with such a name, these footprints have got to be good.

We’ve talked about differential pair calculations before in one of the PCIe articles, and there was a demo video too! That said, let’s repeat the calculations on this one – I’ll show how to get from “PCB fab website information” to “proper width and clearance diffpairs”, with a few fun shortcuts. Our setup is, once again, having signals on outer layers, referenced to the ground layer right below them. I, sadly, don’t yet understand how to calculate differential impedance for signal layers sandwiched between two ground planes, which is to say – if there’s any commenters willing to share this knowledge, I’d appreciate your input tremendously! For now, I don’t see that there’d be a tangible benefit to such an arrangement, anyway.

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Superconducting Tape Leads To A Smaller Tokamak

July 23, 2023 by 80 Comments

Attempts to make a viable nuclear fusion reactor have on the whole been the domain of megabucks projects supported by countries or groups of countries, such as the European JET or newer ITER projects. This is not to say that smaller efforts aren’t capable of making their own advances, operations in both the USA and the UK are working on new reactors that use a novel superconducting tape to achieve a much smaller device.

The reactors in the works from both Oxfordshire-based Tokamak Energy and Massachusetts-based Commonwealth Fusion Systems, or CFS, are tokamaks, a Russian acronym describing a toroidal chamber in which a ring of high-temperature plasma is contained within a spiral magnetic field. Reactors such as JET or ITER are also tokamaks, and among the many challenges facing a tokamak designer is the stable creation and maintenance of that field. In this, the new tokamaks have an ace up their sleeve, in the form of a high-temperature superconducting tape from which those super-powerful magnets can be constructed. This makes the magnets easier to make, cheaper to maintain at their required temperature, and smaller than the low-temperature superconductors found in previous designs.

The world of nuclear fusion is a particularly exciting one to follow in these times of climate crisis, with competing approaches from laser-based devices racing with the tokamak projects to produce the research which will eventually lead to safer carbon-free power. If the CFS or Tokamak Energy reactors lead eventually to a fusion power station on the edge of our cities then it may just be some of the most important work we’ve ever reported.

PCIe For Hackers: An M.2 Card Journey

July 20, 2023 by 22 Comments

I’ve designed a few M.2 adapters for my own and my friends’ use, and having found those designs online, people have asked me for custom-made adapters. One of these requests is quite specific – an adapter that adds one more PCIe link to an E-key M.2 slot, the kind of slot you will see used in laptops for WiFi cards.

See, the M.2 specification allows two separate PCIe links connected to the E-key slot; however, no WiFi cards use this apart from some really old WiGig-capable ones, and manufacturers have long given up on connecting a second link. Nevertheless, there are some cards like the Google Coral M.2 E-key dual AI accelerator and the recently announced uSDR, that do indeed require the second link – otherwise, only half of their capacity is available.

It’s not clear why both Google and WaveletSDR designed for a dual-link E-key socket, since those are a rare occurrence; for the Google card, there are plenty of people complaining that the board they bought just doesn’t fully work. In theory, all you need to do to help such a situation, is getting a second PCIe link from somewhere, then wiring it up to the socket – and a perfect way to do it is to get a PCIe switch chip. You will lose out on some bandwidth because the uplink PCIe connection of the switch can only go so fast; for things like this AI accelerator, it’s not much of a problem since the main point is to get the second device accessible. For the aforementioned SDR, it might turn out useless, or you might win some but lose some – can’t know until you try! Continue reading “PCIe For Hackers: An M.2 Card Journey” →

Open-Source LAMP Instrument Aimed At Clinicians And Biohackers Alike

July 14, 2023 by 28 Comments

Over the last few years, we’ve all been given a valuable lesson in both the promise and limitations of advanced molecular biology methods for clinical diagnostics. Polymerase chain reaction (PCR) was held up as the “gold standard” of COVID-19 testing, but the cost, complexity, and need for advanced instrumentation and operators with specialized training made PCR difficult to scale to the levels demanded by a pandemic.

There are other diagnostic methods, of course, some of which don’t have all the baggage of PCR. RT-LAMP, or reverse transcriptase loop-mediated amplification, is one method with a lot of promise, especially when it can be done on a cheap open-source instrument like qLAMP. For about 50€, qLAMP makes amplification and detection of nucleic acids, like the RNA genome of the SARS-CoV-2 virus, a benchtop operation that can be performed by anyone. LAMP is an isothermal process; it can be done at one single temperature, meaning that no bulky thermal cycler is required. Detection is via the fluorescent dye SYTO 9, which layers into the base pairs inside the amplified DNA strands, using a 470-nm LED for excitation and a photodiode with a filter to detect the emission. Heating is provided by a PCB heater and a 3D-printed aluminum block that holds tubes for eight separate reactions. Everything lives in a 3D-printed case, including the ESP32 which takes care of all the housekeeping and data analysis duties.

With the proper test kits, which cost just a couple of bucks each, qLAMP would be useful for diagnosing a wide range of diseases, and under less-than-ideal conditions. It could also be a boon to biohackers, who could use it for their own citizen science efforts. We saw a LAMP setup at the height of the pandemic that used the Mark 1 eyeball as a detector; this one is far more quantitative.

Orca Slicer Is The New Game In Town

July 13, 2023 by 13 Comments

Slicers are the neat little tools that take your 3D models and turn them into G-code that your 3D printer can actually understand. They control the printing process down to the finest detail, and determine whether your prints are winners or binners. Orca Slicer is the new tool on the block, and [The Edge of Tech] took a look at what it can do.

The video explores the use of Orca Slicer with the Bambu Lab P1P and X1 Carbon. [The Edge of Tech] jumps into the feature set, noting the rich calibration tools that are built right into the software. They work with any printer, and they’re intended to help users get perfect prints time and time again, with less messy defects and print failures. It’s also set up out of the box for network printing and live updates, which is super useful for those with multiple printers and busy workflows. You can even watch camera feeds live in the app from duly equipped printers. It’s even got nifty features for calculating your filament cost per print.

If you’re not happy with your current slicer, give Orca Slicer a go. Let us know what you think in the comments. Video after the break.

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