A RPI HAT For Synchronized Measurements

September 15, 2022 by Dave Rowntree 17 Comments

A team from the Institute for Automation of Complex Power System (ACS) at RWTH Aachen University have been working for a while on the analysis of widely distributed power systems. In a drive to move away from highly specialised (and expensive) electronics platforms, they have produced some instrumentation designed to operate with the Raspberry Pi platform, and an open source software stack. They call the platform the SMU (Synchronised Measurement Unit.) The SMU consists of a HAT sitting on an RPi3, inside a 3D printed box that is intended to attach to a DIN rail. After all, this is supposed to be an industrial platform.

Hardware wise, the star of the show is the Texas Instruments ADS8588S which is a 16-bit 8-channel simultaneous sampling ADC. This is quite a nice device, with 200 kSPS throughput and a per-channel programmable front end, packaged in a hacker-friendly 64-pin QFP. What makes this project interesting however, is how they solved the problem of controlling the sampled data acquisition and synchronisation.

1-PPS and BUSY edges converted to levels, then OR’d to trigger the DMA

By programming the ADC into byte-parallel mode, then using the BCM2837 Secondary Memory Interface (SMI) block together with the DMA, samples are transferred into memory with minimal CPU overhead. An onboard U-Blox Max-M8 GNSS module provides a 1PPS (top of second pulse) signal, which is combined with the ADC busy signal in a very simple manner, enabling both sample rate control as well as synchronisation between multiple units spread out in an installation. They reckon they can get synchronisation to within 180 ns of top-of-second, which for measuring relatively slow-changing power systems, should be enough. The HAT PCB was created in KiCAD and can be found in the SMU GitHub hardware section, making it easy to modify to your needs, or at least adjust the design to match the parts you can actually get your hands on.

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Future Brings CPU Modules, And The Future Is Now

September 14, 2022 by Arya Voronova 36 Comments

Modularity is a fun topic for us. There’s something satisfying about seeing a complex system split into parts and these parts made replaceable. We often want some parts of our devices swapped, after all – for repair or upgrade purposes, and often, it’s just fun to scour eBay for laptop parts, equipping your Thinkpad with the combination of parts that fits you best. Having always been fascinated by modularity, I believe that hackers deserve to know what’s been happening on the CPU module front over the past decade.

A Youtube thumbnail showing a Thinpad in the background with "Not Garbage" written over its keyboard, and one more keyboard overlaid onto the picture with "garbage" written on that one. — This “swap your Thinkpad keyboard” video thumbnail captures a modularity-enabled sentiment many can relate to.

We’ve gotten used to swapping components in desktop PCs, given their unparalleled modularity, and it’s big news when someone tries to split a yet-monolithic concept like a phone or a laptop into modules. Sometimes, the CPU itself is put into a module. From the grandiose idea of Project Ara, to Intel’s Compute Card, to Framework laptop’s standardized motherboards, companies have been trying to capitalize on what CPU module standardization can bring them.

There’s some hobbyist-driven and hobbyist-friendly modular standards, too – the kind you can already use to wrangle a powerful layout-demanding CPU and RAM combo and place it on your simple self-designed board. I’d like to tell you about a few notable modular CPU concepts – their ideas, complexities, constraints and stories. As you work on that one ambitious project of yours – you know, the one, – it’s likely you will benefit a lot from such a standard. Or, perhaps, you’ll find it necessary to design the next standard for others to use – after all, we all know there’s never too few standards! Continue reading “Future Brings CPU Modules, And The Future Is Now” →

How To Be A Stinkin’ Chess Cheat — Sockfish

September 7, 2022 by Jonathan Bennett 18 Comments

[James Stanley] enjoys chess, isn’t terribly good at it, and has some dubious scruples. At least, that’s the setup for building Sockfish, a shoe-to-Pi interface to let you cheat at chess. We’re pretty sure only the first point is true, but the build is impressive all the same. It’s a pair of 3D printed shoe inserts, with two pressure-sensitive inputs on each insert, coupled with a vibration motor in each. Tap out your opponent’s moves during the game, and the Stockfish software will buzz instructions back to you. Just follow the instructions, and you too can be a chess master.

In practice things went a bit awry, as poking in encoded move data with one’s feet isn’t the easiest task, and discerning the subtle tickles on the toes is error-prone at best. [James] arranged a match against an unsuspecting friend (in the name of science), and managed to fat-finger (fat-toe?) the inputs on both games, leading to Sockfish instructing him to make illegal moves.

This seemed like too much cheating, even for [James], so he played the rest of each game on his own abilities, winning one of the two. Once the deed was done, our anti-hero gladly doffed his shoes to show off his gadgetry. After some debate, they concluded the device might “bring the game into disrepute” if used for greater evil. Naturally [James] is already working on an improved version.

Thanks to [Abe Tusk] for the tip!

A Pi Camera To Be Proud Of

August 28, 2022 by Jenny List 16 Comments

The Raspberry Pi HQ camera has appeared in a variety of builds since its introduction back in 2020, and has brought with it many opportunities for photographic projects to compete with the professionals. The latest we’ve been sent is from [Kevin McAleer], who has taken the camera with a full-size Pi and clothed it in a case very similar to the crop of mirror-less compact cameras.

Inside the box is a Waveshare touchscreen that fits on the GPIO header, and a NanoWave 5000 mAH USB battery pack. The camera module fits on the front of the unit, with the C-mount ready to take a lens. Software is still a work in progress and is promised to be a Python script controlling the various camera programs. There are enough Pi camera projects for software to be a matter of choice and taste.

We like the form factor and we like the use of the very compact NanoWave battery, so we think this is a design with some possibilities. Perhaps a cover over the Pi ports might be of use though for general robustness in the face of everyday photography. The question remains though, whether it can come close to the performance of even a budget mirror-less compact camera, and we’re guessing that will depend as much on the operator skill, lens quality, and software capabilities as it does on the Pi HQ module. We look forward to seeing what comes of this project, but meanwhile you can see a video with all the details below the break.

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A Raspberry Pi Handheld Computer You Might Want To Use

August 27, 2022 by Jenny List 49 Comments

Amid the many wonderful form factors being explored by the makers of cyberdecks, there’s one that’s emerged which harks back to an earlier generation of portable computers: the handheld pad with a keyboard. These units are typically around the size of a hardback book, with the upper half being a screen and the lower a keyboard. The latest to come our way is from [Richard Sutherland], and it’s a very tidy pad computer indeed.

Inside the well-designed layered 3D printed case is the frequently-chosen Raspberry Pi 4, along with a PiSugar power supply board and 5,000 mAH battery and a 4.3″ touchscreen display. The keyboard has seen a lot of care and attention, featuring high-quality tactile switches that follow the Miryoku keyboard layout. He says it’s a thumb-typing keyboard, but anyone looking for more can either adapt the design to their liking or simply plug in an external board when faster typing is needed.

We like the pad computer trend as it offers useful computing power in a far more convenient format than a laptop, and we think this is a particularly nice one. It would be nice to see where people take this design, and who knows, we might give one a try for writing some Hackaday articles. If you’d like to see more pad computer goodness, we recently showed you one built in the shell of a classic Amstrad.

YouTube Like It’s 1970s France With This Minitel-VCR Mashup

August 27, 2022 by Dan Maloney 10 Comments

When it’s not just sticking fake gears on things and calling it a day, the Steampunk look is pretty cool. Imagining technology in a world stuck with Victorian aesthetics is a neat idea, and one that translates to the look of other time periods — Fallout, anyone?

But what if you try to create a technological aesthetic based on a more recent and less celebrated time? That’s what [ghettobastler] has attempted with this somewhat bizarre Minitel-YouTube-VCR mash-up. Taking inspiration from a webcomic’s take on “Formicapunk,” modern tech based on the aesthetic of the wildly successful French videotex service of the 70s and 80s, the system uses a very cool Minitel 1B terminal and a Raspberry Pi 3.

With the help of a level-shifting circuit, the Mintel and the Pi talk over serial, allowing the terminal to be used as, well, a terminal for the Pi. Videos are downloaded from YouTube by the Pi, which sends the video to the VCR from its composite output, and controls the VCR with an IR LED that emulates the original remote. Come to think of it, just watch the video below — it’s probably easier than trying to describe it.

It’s weird, true, but we love the look of that Minitel terminal. Something about it just screams cyberdeck; if anyone has a spare one of these, get busy and put something together for our Cyberdeck Design Contest.

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Bit-Banged Ethernet On The Raspberry Pi Pico

August 26, 2022 by Dave Rowntree 29 Comments

Whilst the Raspberry Pi RP2040 is quite a capable little chip, on the whole it’s nothing really special compared to the big brand offerings. But, the PIO peripheral is a bit special, and its inclusion was clearly a masterstroke of foresight, because it has bestowed the platform all kinds of capabilities that would be really hard to do any other way, especially for the price.

Our focus this time is on Ethernet, utilizing the PIO as a simple serialiser to push out a pre-formatted bitstream. [kingyo] so far has managed to implement the Pico-10BASE-T providing the bare minimum of UDP transmission (GitHub project) using only a handful of resistors as a proof of concept. For a safer implementation it is more usual to couple such a thing magnetically, and [kingyo] does show construction of a rudimentary pulse transformer, although off the shelf parts are obviously available for this. For the sake of completeness, it is also possible to capacitively couple Ethernet hardware (checkout this Micrel app note for starters) but it isn’t done all that much in practice.

UDP is a simple Ethernet protocol for transferring application data. Being connection-less, payload data are simply formatted into a packet buffer up front. This is all fine, until you realize that the packets are pretty long and the bitrate can be quite high for a low-cost uC, which is why devices with dedicated Ethernet MAC functionality have a specific hardware serialiser-deserialiser (SERDES) block just for this function.

Like many small uC devices, the RP2040 does not have a MAC function built in, but it does have the PIO, and that can easily be programmed to perform the SERDES function in only a handful of lines of code, albeit only currently operating at 10 MBit/sec. This will cause some connectivity problems for modern switch hardware, as they will likely no longer support this low speed, but that’s easily solved by snagging some older switch hardware off eBay.

As for the UDP receive, that is promised for the future, but for getting data out of a remote device over a wired network, Pico-10BASE-T is a pretty good starting point. We’ve seen a few projects before that utilize the PIO to generate high speed signals, such as DVI, albeit with a heavy dose of overclocking needed. If you want a bit more of an intro to all things Pico, you could do worse than check out this video series we highlighted a while back.