Hackaday Columns

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This excellent content from the Hackaday writing crew highlights recurring topics and popular series like Linux-Fu, 3D-Printering, Hackaday Links, This Week in Security, Inputs of Interest, Profiles in Science, Retrotechtacular, Ask Hackaday, Teardowns, Reviews, and many more.

Hackaday Podcast Episode Ep 377: Parallel Pixels, Wiggly Consoles, And Seven Segments

July 10, 2026 by No comments

This week’s podcast sees Elliot joined by Jenny List, as both suffer silently in the European summer heat because the sound of a desk fan would come over on the recording.

A stand-out hack of the week comes from [Bitluni], whose GPU made from thousands of cheap microcontrollers is on a scale we’ve never seen before. It’s an amazing project in itself, but the manufacturing and power consumption issues of so many processors running at the same time make for a discussion of their own.

Otherwise, we have diecasting on the bench, an impressive achievement by any measure, a Raman spectrometer, and an open source take on something like a Kei truck. In quick hacks there’s a dicussion of soldering versus crimping for high current connectors, and neon tubes used as digital logic in an organ. The recording finishes with a discussion of 7-segment display history, and whether an engineering education teaches design for manufacture.

Or download it yourself, in glorious 192-bit MP3.

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This Week In Security: Escaping Linux VMs, Vulnerable Solar, Confusing AI (Again), And Confusing NPM Malware

July 10, 2026 by No comments

The Januscape vulnerability allows a user in a guest VM managed by the Linux Kernel Virtual Machine (KVM) to corrupt memory in the host system and break out of isolation.

KVM virtualization is used by major hosting platforms like Amazon AWS, Google GCP, Digital Ocean, and many more. All of the shared hosting platforms count on virtualization to isolate untrusted guest systems from the physical hardware and each other; being able to corrupt memory for all guests or break isolation presents a major threat.

The bug report says the error has been present for 16 years, which is nearly the entire lifetime of the KVM subsystem in Linux. Fixes are available in mainline, and major hosting providers who count on KVM are likely already updating.

Vulnerabilities In Balcony Solar

Micro solar, or “balcony solar”, installs have been gaining traction in Europe as a way to offset rising electrical costs by connecting solar and battery systems to a house or apartment power system.

Vulnerabilities have been found in the popular Hoymiles micro-inverter, which uses a proprietary RF radio protocol to manage the devices. Unfortunately, it looks like this protocol has no encryption or authentication beyond validating the serial number, and the serial number is also available over a wireless probe command.

Armed with a Nordic nRF radio researchers were able to discover nearby inverters in the wild and collect the serial numbers, though of course they stopped short of issuing commands to random users.

The wireless management control allows controlling the device power and output levels, as well as setting a lockout PIN, which the researchers suspect could be used to disable devices and lock the legitimate owners out completely.

There are an estimated 500,000 units in use, and currently the only known mitigation is to unplug the device entirely and disconnect the solar panels, though the team suggests that setting an anti-theft PIN may also help – or at least prevent an unknown PIN being set.

Be sure to check out the link for an in-depth analysis of the protocol and the surprising lack of protection.

Continue reading “This Week In Security: Escaping Linux VMs, Vulnerable Solar, Confusing AI (Again), And Confusing NPM Malware” →

Linux Fu: The Local Phonebook

July 8, 2026 by 30 Comments

I’ll admit it: I miss the simplicity of /etc/hosts. There was something elegant about it. You wanted laserprinter to mean 192.168.1.40, so you opened a text file and wrote:

192.168.1.40 laserprinter

Done. No cloud account, no discovery daemon, no dashboard with material-themed icons. Just a name and an address. The trouble, of course, is that /etc/hosts is only simple when you have one machine. The moment you have a desktop, a laptop, a Raspberry Pi, a NAS, a test box, and a phone or two, every little network change becomes a tiny distributed-database problem. Which copy of /etc/hosts is authoritative? Did you update the laptop? What about the machine you only boot once a month?

One Solution

Modern LANs solved this with mDNS, using Avahi on Linux. It resolves addresses that end in .local. Instead of asking a central DNS server “who is thing.local?”, a machine sends a multicast query on the local network: “who has thing.local?” The device that owns the name answers. This is why your Linux box named spock and usually be reached as spock.local on your LAN.

There are limits. mDNS is link-local; it is meant for the local LAN, not the whole Internet and shouldn’t route across subnets. Each device is supposed to publish its own name. That works fine when the device cooperates. But what about devices that do not publish mDNS? Or little embedded things that barely even have an IP address?

That is where I wanted the best of both worlds: keep a small authoritative /etc/hosts file on one Linux box, but publish selected entries onto the LAN using mDNS.

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When An Engineering Education Doesn’t Teach You How To Really Make Anything

July 7, 2026 by 100 Comments

In the sweltering temperatures of an unusually hot European heatwave, I found myself having a chat with  a friend of mine from my university days. After discussing the health of his cat who had solved the problem of a fur coat on a hot day by flattening himself out on the concrete floor in the coolest place in the house, we moved on to tech matters. We’ve known each other for not far short of four decades, so this is familiar territory for us. The problems that come with taking a prototype to manufacturing, a process which even the most seasoned of engineers can slip up on.

The Difference Between Making, And Making For Manufacture

If you’ve ever taken a project and replicated it, you will know the progression. If you’re making five or ten widgets, you can debug and rework as needed, tweak things, and get things going. If you’re making more then this, the process consumes a greater proportion of your time, until a point at which manufacture becomes impractical. Maybe that’s around fifty boards, sometimes more or less. Continue reading “When An Engineering Education Doesn’t Teach You How To Really Make Anything” →

Hackaday Europe 2026: Is Your Blood Pressure Monitor Lying To You?

July 6, 2026 by 21 Comments

Blood pressure is one of the so-called “vital signs” that medical practitioners use to determine the basic state of a patient in any given moment. It’s exactly what it sounds like—a measurement of the pressure of the blood flowing through the body, with some complications to account for the pulsatile nature of human blood flow.

You might think measuring blood pressure is a solved concern, and it mostly is. With that said, some blood pressure monitors out there aren’t quite doing their job properly, and [Milos Rasic] came to Hackaday Europe 2026 to spell out the problem.

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Hackaday Links: July 5, 2026

July 5, 2026 by 8 Comments

Happy belated July 4th to all the readers from the United States — hopefully you aren’t reading this from a hospital bed after losing a hand or burning off your eyebrows. While we suspect amateur firework shows and their related injuries will be around for many years to come, we did note that many major cities switched over to drone shows this year.

At least on paper, the appeal is obvious. Beyond the fact that drones are safer and quieter than pyrotechnics, they’re also capable of far more complex displays. Good luck trying to draw George Washington’s face in the sky with exploding rockets. But even if it’s a little more than nostalgia, there’s still something about the sights and sounds of fireworks that enthrall audiences. For many, the whole “rockets’ red glare” thing is a bit more meaningful than the “drones’ red LEDs.”

Earlier this week, we brought you news that Sony would stop producing physical PlayStation discs in January 2028. Many gamers are understandably concerned about the long-term implications such a move will have for software ownership, and while the negative reactions online haven’t bothered Sony enough to get them to amend their plans, they have clarified the situation with developers by explaining that games published before the cutoff date aren’t impacted. So if a developer has a hit title that drops in the summer of 2027 and they want to keep cranking out discs, additional orders can still be placed. Not much of a reprieve, but it will give the community a little more time to figure out what comes next.

Continue reading “Hackaday Links: July 5, 2026” →