PDP-11 Trouble With A Ruthless Power Supply Issue

After [David Lovett] of [Usagi Electric] was donated a few cars full of DEC PDP-11 minicomputers of various flavors and vintages, he passed on most of them to loving homes, but kept a few of them himself. One goal of this being to put together a PDP-11 system that could be more easily taken to vintage computer shows than the ‘rollable’ PDP-11s he had access to prior. Of 1980s PDP-11s, the first-generation Large Scale Integration (LSI) PDP11/03 system (so-called Q-Bus models) is among the smallest, taking up about as much space as a 1980s desktop PC, while supporting the second generation LSI PDP-11/23 cards. It all seemed so easy until [David] tried testing the PDP-11/03’s PSU and everything went south.

Despite having access to the circuit diagrams of the PSU, figuring out what was going wrong was an absolute nightmare for [David], after some easy fixes involving replacing a blown fuse and bulging capacitors failed to deliver salvation. Reading through the comments to the video, it would seem that people are generally confused about whether this PSU is a linear, switching or some other configuration. What is clear is that with the absolutely massive transformer, it looks more like a linear power supply, but with a lot of protections against over current and other failure modes built-in, all of which rely on transistors and other components that could have gone bad.

Although in round 1 the PDP-11/03 PSU won the battle, we hope that once round 2 commences [David] will have had the proverbial training montage behind him (set to ‘Eye of the Usagi’, probably) and will manage to get this PSU working once more.

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Feeding The Fire By Robot

It might seem a little bit counterintuitive, but one of the more carbon-neutral ways of heating one’s home is by burning wood. Since the carbon for the trees came out of the air a geologically insignificant amount of time ago, it’s in effect solar energy with extra steps. And with modern stoves and well-seasoned wood, air pollution is minimized as well. The only downside is needing to feed the fire frequently, which [Anders] solved by building a robot.

[Anders]’ system is centered around a boiler, a system which typically sits in a utility area like a basement and directs its heat to the home via another system, usually hot water. An Arduino Mega controls the system of old boat winches and various motors, with a grabber arm mounted at the end. The arm pinches each log from end to end, allowing it to grab the uneven logs one at a time. The robot also opens the boiler door and closes it again when the log is added, and then the system waits for the correct set of temperature conditions before grabbing another log and adding it. And everything can be monitored remotely with the help of an ESP32.

The robot is reportedly low-maintenance as well, thanks to its low speed and relatively low need for precision. The low speed also makes it fairly safe to work around, which was an important consideration because wood still needs to be added to a series of channels every so often to feed the robot, but this is much less often than one would have to feed logs into a boiler if doing this chore manually. It also improves on other automated wood-burning systems like pellet stoves, since you can skip the pellet-producing middleman step. It also eliminates the need to heat your home by burning fossil fuels, much like this semi-automated wood stove.

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Reverse-Engineering The ESP32’s WiFi Binary Blob With A Faraday Cage

The Faraday cage constructed by Jasper Devreker.
The Faraday cage constructed by Jasper Devreker.

As part of a team reverse-engineering the binary blob driver for the ESP32’s WiFi feature at Ghent University, [Jasper Devreker] saw himself faced with the need to better isolate the network packets coming from the ESP32-under-test. This is a tough call in today’s WiFi and 2.4 GHz flooded airwaves. To eliminate all this noise, [Jasper] had to build a Faraday cage, but ideally without racking up a massive invoice and/or relying on second-hand parts scavenged from eBay.

We previously reported on this reverse-engineering project, which has since seen an update. Although progress has been made, filtering out just the packets they were interested in was a big challenge. The solution was a Faraday cage, but on a tight budget.

Rather than relying on exotic power filters, [Jasper] put a battery inside a Faraday cage he constructed out of wood and conductive fabric. To get Ethernet data in and out, a fiber link was used inside a copper tube. Initial testing was done using a Raspberry Pi running usbip and a WiFi dongle.  The Faraday cage provided enough attenuation that the dongle couldn’t pick up any external WiFi signals in listening mode.

The total cost of this build came down to a hair over €291, which makes it feasible for a lot of RF experiments by hobbyists and others. We wish [Jasper] and the rest of the team a lot of luck in figuring out the remaining secrets of Espressif’s binary WiFi blob using this new tool.

USB-C PD: New Technology Done Right

There is a tendency as we get older, to retreat into an instinctive suspicion of anything new or associated with young people. All of us will know older people who have fallen down this rabbit hole, and certainly anything to do with technological advancement is often high on their list of ills which beset society. There’s a Douglas Adams passage which sums it up nicely:

“I’ve come up with a set of rules that describe our reactions to technologies:
1. Anything that is in the world when you’re born is normal and ordinary and is just a natural part of the way the world works.
2. Anything that’s invented between when you’re fifteen and thirty-five is new and exciting and revolutionary and you can probably get a career in it.
3. Anything invented after you’re thirty-five is against the natural order of things.”

Here at Hackaday we’re just like anybody else, in that we all get older. Our lives are devoted to an insatiable appetite for new technology, but are we susceptible to the same trap, and could we see something as against the antural order of things simply because we don’t like it? It’s something that has been on my mind in some way since I wrote a piece back in 2020 railing at the ridiculous overuse of new technologies to limit the lifespan and repairability of new cars and then a manifesto for how the industry might fix it, am I railing against it simply because I can’t fix it with a screwdriver in the way I could my 1960 Triumph Herald? I don’t think so, and to demonstrate why I’d like to talk about another piece of complex new technology that has got everything right.

In 2017 I lamented the lack of a universal low voltage DC power socket that was useful, but reading the piece here in 2024 it’s very obvious that in the years since my quest has been solved. USB Power Delivery was a standard back then, but hadn’t made the jump to the ubiquity the USB-C-based power plug and socket enjoys today. Most laptops still had proprietary barrel jack connectors, and there were still plenty of phones with micro-USB sockets. In the years since it’s become the go-to power standard, and there are a huge number of modules and devices to supply and receive it at pretty high power.

At first sight though, it might seem as though USB-PD is simply putting a piece of unnecessary technology in the way of what should be a simple DC connector. Each and every USB-PD connection requires some kind of chip to manage it, to negotiate the connection, and to transform voltage. Isn’t that the same as the cars, using extra technology merely for the sake of complexity? On the face of it you might think so, but the beauty lies in it being a universally accepted standard. If car manufacturers needed the same functionalty you’d have modules doing similar things in a Toyota, a Ford, or a Renault, but they would all be proprietary and they’d be eye-wateringly expensive to replace. Meanwhile USB-PD modules have to work with each other, so they have become a universal component available for not a huge cost. I have several bags of assorted modules in a box of parts here, and no doubt you do too. The significant complexity of the USB-PD endpoint doesn’t matter any more, because should it break then replacing it is an easy and cheap process.

This is not to say that USB-PD is without its problems though, the plethora of different cable standards is its Achilies’ heel. But if you’re every accused of a knee-jerk reaction to a bad piece of new technology simply because it’s new, point them to it as perhaps the perfect example of the responsible use of new technology.

Neutrino Hunters Hack Chat

Join us on Wednesday, January 17 at noon Pacific for the Neutrino Hunters Hack Chat with Patrick Allison!

It’s a paradox of science that the biggest of equipment is needed to study the smallest of phenomena. The bestiary of subatomic particles often requires the power and dimension of massive accelerators to produce, and caverns crammed with racks full of instruments to monitor their brief but energetic lives. Neutrinos, though, are different. These tiny, nearly massless, neutral particles are abundant in the extreme, zipping through space from sources both natural and artificial and passing through normal matter like it isn’t even there.

That poses a problem: how do you study something that doesn’t interact with the stuff you can make detectors out of? There are tricks that neutrino hunters use, and most of them use very, VERY big instruments to do it. Think enormous tanks of ultrapure water or a cubic kilometer of Antarctic ice, filled with photomultiplier tubes to watch for the slightest glimmer of Cherenkov radiation as a neutrino passes by.

join-hack-chatNeutrino hunting is some of the biggest of Big Science, and getting all the parts to work together takes some special engineering. Patrick Allison has been in the neutrino business for decades, both as a physicist and as the designated guru who keeps all the electronics humming. He’ll join us on the Hack Chat to talk about the neutrino hunting trade, and what it takes to keep the data flowing.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, January 17 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Featured image: Daderot, CC0, via Wikimedia Commons

Haiku OS: The Open Source BeOS You Can Daily Drive In 2024

Haiku is one of those open source operating systems that seem to be both exceedingly well-known while flying completely under the radar. Part of this is probably due to it being an open source version and continuation of the Be Operating System (BeOS). Despite its strong feature set in the 1990s, BeOS never got much love in the wider computer market. Nevertheless, it has a strong community that after twenty-two years of development has now reached a point where you can daily drive it, according to the [Action Retro] channel on YouTube.

One point where Haiku definitely scores points is with the super-fast installation and boot. [Action Retro] demonstrates this on real hardware, and we can confirm that it boots very fast in VirtualBox on a low-end Intel N100-based host system as well. With the recently introduced QtWebEngine-based Falkon browser (formerly known as QupZilla) even JavaScript-heavy sites like YouTube and retro Mac emulators work well. You can even get a Minecraft client for Haiku.

Although [Action Retro] notes that 3D acceleration is still a work-in-progress for Haiku, his 2014-era AMD system smoothly played back 1080p YouTube videos. Although not addressed in the video, Haiku is relatively easy to port existing software to, as it is POSIX-compatible. There is a relatively modern GCC 11.2 compiler in the Beta 4 release from 2022, backed up by solid API documentation. Who doesn’t want to take a poke at a modern take on the OS that nearly became MacOS?

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Solar Chimneys: Viable Energy Solution Or A Lot Of Hot Air?

We think of the power we generate as coming from all these different kinds of sources. Oil, gas, coal, nuclear, wind… so varied! And yet they all fundamentally come down to moving a gas through a turbine to actually spin up a generator and make some juice. Even some solar plants worked this way, using the sun’s energy to heat water into steam to spin some blades and keep the lights on.

A solar updraft tower works along these basic principles, too, but in a rather unique configuration. It’s not since the dawn of the Industrial Age that humanity went around building lots of big chimneys, and if this technology makes good sense, we could be due again. Let’s find out how it works and if it’s worth all the bluster, or if it’s just a bunch of hot air.

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