Your Surface RT Can Become Useful Again, With Raspberry Pi OS

February 2, 2024 by Jenny List 20 Comments

Over the years there have been so many times when Microsoft came up with a product that so nearly got it right, but which tanked in the market because the folks at Redmond had more of an eye to what fitted their strategy than what the customer wanted. The Surface RT was one of these: while the hardware was at least as good if not better than Apple’s iPad, its ARM CPU and an ill-advised signed-apps-only policy meant the tablet couldn’t access the huge existing library of Windows software.

Consumers didn’t want a tablet with next-to-no apps, so it failed miserably. Never mind though, because [Michael MJD] has a video showing how an RT can be given a new life from an unlikely source, with the installation of Raspberry Pi OS.

The video pretty closely follows this guide, and involves creating a Raspberry Pi OS install medium modified with RT-specific kernel modules and device tree. It’s possible because the 32-bit ARM architecture is one of those which Raspberry Pi OS targets, and while a few things such as graphics acceleration don’t work, it’s still successful (if a little slow).

Oddly this is a technique not unlike one from the earliest days of the Raspberry Pi, when we remember people in Raspberry Pi Jams showing off the ancestor of the modern OS running on cheap ARM-based netbooks. In those cases the hack relied on transplanting the Pi userland over the device’s existing kernel, we’d be interested in an explanation of how the RT can use the Pi kernel without the famous Broadcom BLOB intended for the Pi.

We have a soft spot for the RT, as we said a good product held back by a very bad software decision. Seeing it take a new life years later is thus pleasing to us.

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Will There Be Any Pi Left For Us?

February 2, 2024 by Jenny List 72 Comments

Our world has been abuzz with the news that Raspberry Pi are to float on the London Stock Exchange. It seems an obvious move for a successful and ambitious company, and as they seem to be in transition from a maker of small computers into a maker of chips which happen to also go on their small computers, they will no doubt be using the float to generate the required investment to complete that process.

New Silicon Needs Lots Of Cash

An RP1 chip on a Raspberry Pi 5. — The most important product Raspberry Pi have ever made.

When a tech startup with immense goodwill grows in this way, there’s always a worry that it could mark the start of the decline. You might for instance be concerned that a floated Raspberry Pi could bring in financial whiz-kids who let the hobbyist products wither on the vine as they license the brand here and there and perform all sorts of financial trickery in search of shareholder value and not much else. Fortunately we don’t think that this will be the case, and Eben Upton has gone to great lengths to reassure the world that his diminutive computers are safe. That is however not to say that there might be pitfalls ahead from a hobbyist Pi customer perspective, so it’s worth examining what this could mean.

As we remarked last year, the move into silicon is probably the most important part of the Pi strategy for the 2020s. The RP2040 microcontroller was the right chip with the right inventory to do well from the pandemic shortages, and on the SBCs the RP1 all-in-one peripheral gives them independence from a CPU house such as Broadcom. It’s not a difficult prediction that they will proceed further into silicon, and it wouldn’t surprise us to see a future RP chip containing a fully-fledged SoC and GPU. Compared to their many competitors who rely on phone and tablet SoCs, this would give the Pi boards a crucial edge in terms of supply chain, and control over the software.

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Multi-way Capacitor Replacement Without The Pain

February 1, 2024 by Jenny List 20 Comments

Anyone who’s worked with older tube-based equipment will be familiar with the type of vintage electrolytic capacitor which integrated several capacitors into one can. Long obsolete, they can be bought as reproduction, but unfortunately at an eye-watering price. [D-Lab Electronics] introduces us to a solution using a very useful kit, that it’s worth sharing.

The piece of equipment in the video below the break is a rather lovely Heathkit oscillator, following the familiar phase shift model with a light bulb in its feedback loop. It’s a piece of test equipment that produces a low-distortion sine wave output, and would still be of use to an audio engineer today. He replaces the capacitor with two modern ones on a multi-cap board from [W8AOR], who sells a variety of these kits for different configurations.

We’ve done this very repair more than once, and it has usually involved wiring, heatshrink sleeving, hot glue, and cable ties, looking very messy indeed. It’s not that often that a kit catches our eye as this one has, but we know we’ll be finding it useful here some time in the future. Meanwhile if you’d like to know why this oscillator has a light bulb, take a look at our piece on distortion.

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This Time It’s Toyota: Takata Airbag Recalls Continue

February 1, 2024 by Jenny List 22 Comments

The automotive industry is subject to frequent product recalls, as manufacturers correct defects in their vehicles that reveal themselves only after some use. While such events may be embarrassing for a marque, it’s not necessarily a bad thing — after all, we would rather put our trust in a carmaker prepared to own up and fix things rather than sweep their woes under the carpet.

There’s one recall that’s been going on for years which isn’t the vehicle manufacturer’s fault though, and now it seems Toyota are the latest to be hit, with some vehicles as old as two decades being part of it. Long time Hackaday readers will probably recognize where this is going as we’ve covered it before; at its centre are faulty airbag charges from Takata, and the result has been one of the largest safety related recalls in automotive history.

An automotive airbag is a fabric structure inflated at high speed by a small explosive charge when triggered by the sharp deceleration of an incident. It is intended to cushion any impact the occupant might make upon the car’s interior. The problem with the faulty Takata units is that moisture ingress could alter the properties of the charge, and this along with corrosion could increase its power and produce a hail of metal fragments on detonation.

Our colleague [Lewin Day] has penned a series of informative and insightful investigations of the technology behind the Takata scandal, going back quite a few years. With such relatively ancient vehicles now being recalled we can’t help wondering whether it would be easier for Toyota to run a buyback scheme and take the cars off the road rather than fix them in this case, but we’re curious as non automotive safety engineers why the automotive airbag has evolved in this manner. Why is one of very few consumer explosive devices not better regulated, why is it sold with an unlimited lifetime, and why are they not standardized for routine replacement on a regular schedule just like any other vehicle consumable?

2003-2004 Toyota Corolla: IFCAR, Public domain.

Making An Aircraft Wing Work For An Audience

January 31, 2024 by Jenny List 3 Comments

Many of us will have sat and idly watched the flaps and other moving parts of an airliner wing as we travel, and it’s likely that most of you will know the basics of how an aircraft wing works. But there’s more to an aircraft wing than meets the eye, which is why the Aerospace Bristol museum has an Airbus A320 wing on display. [Chris Lymas] was part of the team which turned a surplus piece of aircraft into an interactive and working exhibit, and he told the Electromagnetic Field audience all about it in his talk Using Arduinos to Resurrect an Airliner Wing.

The talk starts with an explanation of how a variable surface wing works, and then starts to talk about the control systems employed. We’re struck with the similarity to industrial robots, in that this is a a powerful and thus surprisingly dangerous machine to be close to. The various moving surfaces are moved by a series of shafts and gearboxes, driven by a DC motor. Running the show is an Arduino Mega, which has enough interfaces for all the various limit switches.

It’s fascinating to see how the moving parts in an airliner wing work up close, and we’re impressed at the scale of the parts which keep us safe as we fly. Take a look, the video is below the break.

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A Basic USB-C Primer

January 30, 2024 by Jenny List 32 Comments

Over the last five years or so there has been a quiet take-over of the ports on laptops, phones, and other devices, as a variety of older ports as well as the familiar USB A and micro USB sockets have been replaced by the now-ubiquitous USB-C port. It’s a connector which can do so many things, so many in fact that it bears a handy explanation. The Electromagnetic Field 2022 hacker camp has been quietly uploading videos of its talks, and a recent one has [Tyler Ward] explaining the intricacies of the interface.

Many of you will be familiar with XKCD number 927 which makes a joke about proliferating connector standards, and it’s evident that USB-C is a rare case of a connector which bucks the trend of simply making another standard, and has instead created something with which it makes sense to replace what went before. We learn about the intricacies of inter-device communications and USB-PD, and the multiple high-speed connection lanes shoehorned into it. That one small connector can plug into a laptop and provide power, USB peripherals including network, and display, is nothing short of amazing. Take a look at the video below the break, and if you’re interested in diving deeper, have a look at our colleague [Arya Voronova]’s USB-C for hackers series.

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A Complete Exchange From Scratch For Your Rotary Dial Phones

January 29, 2024 by Jenny List 12 Comments

Such has been the success of the mobile phone that in many places they have removed the need for wired connections, for example where this is being written the old copper connection can only be made via an emulated phone line on an internet router. That doesn’t mean that wired phones are no longer of interest to a hardware hacker though, and many of us have at times experimented with these obsolete instruments. At the recent 37C3 event in Germany, [Hans Gelke] gave a talk on the analog exchange he’s created from scratch.

The basic form of the circuit is built around a crosspoint switch array, with interfaces for each line and a Raspberry Pi to control it all. But that simple description doesn’t fully express its awesomeness, rather than hooking up a set of off-the-shelf modules he’s designed everything himself from scratch. His subscriber line interface circuit uses a motor controller to generate the bell signal, his analogue splitter has an op-amp and a transistor, and his crosspoint array is a collection of JFETs. Having dabbled in these matters ourselves, it’s fascinating to see someone else making this work. Video below the break.

Have an analogue phone but nowhere to use it? Bring it to a hacker camp!

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