Generating PAL Video With A Heavily Overclocked Pi Pico

January 24, 2023 by Dave Rowntree 19 Comments

Barely a week goes by without another hack blessing the RP2040 with a further interfacing superpower. This time it’s the turn of the humble PAL standard composite video interface. As many of us of at least a certain vintage will be familiar with, the Phase Alternate Line (PAL to friends) standard was used mainly in Europe (not France, they used SECAM like Russia, China, and co) and Australasia, and is a little different from the much earlier NTSC standard those in the US may fondly recollect. Anyway, [Fred] stresses that this hack isn’t for the faint-hearted, as the RP2040 needs one heck of an overclock (up to 312 MHz, some 241% over stock) to be able to pull off the needed amount of processing grunt. This is much more than yet another PIO hack.

The dual cores of the RP2040 are really being pushed here. The software is split into high and low-level functions, with the first core running rendering the various still images and video demos into a framebuffer. The second core runs in parallel and deals with all the nitty-gritty of formatting the frame buffer into a PAL-encoded signal, which is then sucked out by the DMA and pushed to the outside world via the PIO. There may be a few opportunities for speeding the code up even more, but [Fred] has clearly already done a huge amount of work there, just to get it working at all. The PIO code itself is very simple but is instructive as a good example of how to use multiple chained DMA channels to push data through the PIO at the fastest possible rate.

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The Tale Of The Final EVGA GPU Overclocking Record

January 23, 2023 by Dave Rowntree 12 Comments

It’s not news that EVGA is getting out of the GPU card game, after a ‘little falling out’ with Nvidia. It’s sad news nonetheless, as this enthusiastic band of hardware hackers has a solid following in certain overclocking and custom PC circles. The Games Nexus gang decided to fly over to meet up with the EVGA team in Zhonghe, Taiwan, and follow them around a bit as they tried for one last overclocking record on the latest (unreleased, GTX4090-based) GPU card. As you will note early on in the video, things didn’t go smoothly, with their hand-lapped GPU burning out the PCB after a small setup error. Continue reading “The Tale Of The Final EVGA GPU Overclocking Record” →

DIY capacitor leakage tester nestled among neighbours all mounted underneath a shelf

DIY Capacitor Leakage Tester With A Professional Finish

January 22, 2023 by Dave Rowntree 7 Comments

[Manuel Caldeira] has built a nice electronics work area that would be the envy of many, complete with an under-shelf rail of custom-built instruments that are specific to the needs of areas of electronics that [Manuel] is involved with. The highlighted project here is a capacitor leakage tester, which is very handy for sorting through piles of old parts looking for anything still within spec, or just verifying a part on a board is the culprit you suspect it is.

The thing is, certain types of capacitors have a limited life both in operation and in storage. Usually, we’re talking about electrolytics here, where the electrolyte solution can leak out or dry out, but also the passive oxide layer on the anode plate can deteriorate if the device is left unpowered for long periods — the oxide disintegrates, and the capacitor will start to leak current. Eventually, the breakdown can be bad enough for the capacitor to conduct so well that it overheats and the result can be a surprisingly violent experience. So, if you deal with capacitors a lot, especially electrolytics, then a leakage tester is a very good instrument to own.

We like [Manuel]’s construction method here, with custom PCBs nestled inside a simple bent aluminium enclosure. No need for a top or sides, as these, are intended to bolt underneath a shelf, and butt up against their neighbor. The front panel graphics are done in a simple but very effective manner, using printable sticker sheets, with a clear adhesive over-sheet. They certainly have a professional finish, and this is definitely a construction method worth considering.

For those a little unfamiliar with this important component, why not leap into some theory with this handy dive into the simple parallel plate capacitor? Next, may we suggest a little overview of the different capacitor types and how to best make use of them?

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open hardware textile spinning machine constructed from aluminium extrusions, arduino electronics and 3D printed parts

An Open Hardware Automatic Spinning Machine

January 21, 2023 by Dave Rowntree 6 Comments

The team at the Berlin-based Studio HILO has been working on ideas and tools around developing a more open approach to small-scale textile production environments. Leveraging open-source platforms and tools, the team has come up with a simple open hardware spinning machine that can be used for interactive yarn production, right on the desktop. The frame is built with 3030 profile aluminium extrusions, with a handful of 3D printed, and a smidge of laser cut parts. Motion is thanks to, you guessed it, NEMA 17 stepper motors and the once ubiquitous Arduino Mega 2560 plus RAMPS 1.4 combination that many people will be very familiar with.

The project really shines on the documentation side of things, with the project GitLab positively dripping with well-organised information. One minor niggle is that you’ll need access to a polyjet or very accurate multi-material 3D printer to run off the drive wheel and the associated trailing wheel. We’re sure there’s a simple enough way to do it without those tools, for those sufficiently motivated.

We liked the use of Arduino for the firmware, keeping things simple, and in the same vein, Processing for the user interface. That makes sending values from the on-screen slider controls over the USB a piece of cake. Processing doesn’t seem to pop up on these pages too often, which is a shame as it’s a great tool to have at one’s disposal. On the subject of the user interface, it looks like for now only basic parameters can be tweaked on the fly, with some more subtle parameters needing fixing at firmware compilation time. With a bit more time, we’re sure the project will flesh out a bit more, and that area will be improved.

Of course, if you only have raw fibers, that are not appropriately aligned, you need a carder, like this one maybe?

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RP2040 DMA Hack Makes Another ‘CPU Core’

January 20, 2023 by Dave Rowntree 16 Comments

[Bruce Land] of Cornell University will be a familiar name to many Hackaday readers, searching the site for ‘ECE4760′ will bring up many interesting topics around embedded programming. Every year [Bruce] releases yet more of the students’ work out into the wild to our great delight. This RP2040-based project is a bit more abstract than some previous work and shows yet another implementation of an older hack to utilise the DMA hardware of the RP2040 as another CPU core. While the primary focus of the RP2040 DMA subsystem is moving data between memory spaces, with minimal CPU intervention, the DMA control blocks have some fairly complex behaviour. This allows for a Turing-complete CPU to be implemented purely with the DMA hardware and a sprinkling of memory.

The method ties up three of the twelve DMA channels, and is estimated to have a similar performance to ‘an Arduino’ but [Bruce] doesn’t specify which one of the varied models that could be. But who cares anyway? Programming the CPU is a matter of leveraging the behaviour of the hardware, which is all memory mapped and targetable by the DMA. For example, the CPU can waggle GPIO pins by using the DMA to write values to the peripheral address space. The basic flow can be seen in the image above. DMA0 is used as the program counter, which points DMA1 to an array of DMA control blocks, a sequence of which codes for some of the ‘opcodes’ of the CPU model. DMA0 chains to (hands over control to) DMA1 which reads the control blocks and configures itself accordingly. DMA1 performs whatever data move is programmed, chains to DMA2, which in turn reprograms the DMA0 program counter to point to the next block in the list to be executed by DMA1.

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Chataigne: An Open-Source Swiss Army Knife

January 6, 2023 by Dave Rowntree 47 Comments

[Ben Kuper] is a developer with a history of working on art installations, and had hit upon a common problem often cited by artists. When creating installations involving light, sound, and motion, they often spend too much time on the nuts and bolts of electronics, programming, and so on. Such matters are a huge time sink with a steep learning curve and oftentimes just a plain distraction from the actual artistic intent they’re trying to focus upon. [Ben] has been working for a few years on a software tool, Chataigne which is designed as the glue between various software tools and hardware interfaces, enabling complex control of the application using simple building blocks. Continue reading “Chataigne: An Open-Source Swiss Army Knife” →

AIOC: The Ham Radio All-In-One Cable For Audio And APRS

January 1, 2023 by Dave Rowntree 23 Comments

The Ham Radio All-in-one cable (AIOC) is a small PCB attachment for a popular series of radio transceivers which adds a USB-attached audio interface and virtual TTY port for programming and the push-to-talk function. The STM32F373 microcontroller (which, sadly is still hard to find in the usual channels) is a perfect fit for this application, with all the needed hardware resources.

With USB-C connectivity, the AIOC enumerates as a sound card as well as a virtual serial device, so interfacing to practically any host computer should be plug-and-play. Connection to the radio uses 12mm separation 3.5mm and 2.5mm TRS connectors, so is compatible with at least the Baofeng UV-5R but likely many other cheap transceivers that have the same physical setup.

Instructions are provided to use the AIOC with Dire Wolf for easy access to APRS applications, which makes a nice out-of-the-box demo to get you going. APRS is not all about tracking things though since other applications can sit atop the APRS/AX.25 network, for example, HROT: the ham radio of things.

We’ve seen quite a few Baofeng (and related products) hacks, like this sketchy pile of wires allowing one to experiment with the guts of the radio for APRS. Of course, such cheap radio transceivers cut so many engineering corners that there are movements to ban their sale, so maybe a new batch of better radios from our friends in the East is on the horizon?

Thanks to [Hspil] for the tip!