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.
We ran an article this week about RS-485, a noise resistant differential serial multidrop bus architecture. (Tell me where else you’re going to read articles like that!) I’ve had my fun with RS-485 in the past, and reading this piece reminded me of those days.
You see, RS-485 lets you connect a whole slew of devices up to a single bundle of Cat5 cable, and if you combine it with the Modbus protocol, you can have them work together in a network. Dedicate a couple of those Cat5 lines to power, and it’s the perfect recipe for a home, or hackerspace, small-device network — the kind of things that you, and I, would do with WiFi and an ESP8266 today.
Wired is more reliable, has fewer moving parts, and can solve the “how do I get power to these things” problem. It’s intrinsically simpler: no radios, just serial data running as voltage over wires. But nobody likes running cable, and there’s just so much more demo code out there for an ESP solution. There’s an undeniable ease of development and cross-device compatibility with WiFi. Your devices can speak directly to a computer, or to the whole Internet. And that’s been the death of wired.
Still, some part of me admires the purpose-built simplicity and the bombproof nature of the wired bus. It feels somehow retro, but maybe I’ll break out some old Cat5 and run it around the office just for old times’ sake.
This article is part of the Hackaday.com newsletter, delivered every seven days for each of the last 200+ weeks. It also includes our favorite articles from the last seven days that you can see on the web version of the newsletter.
Want this type of article to hit your inbox every Friday morning? You should sign up!
Thanks to the relatively recent rise of affordable board production services, many of the people reading Hackaday are just now learning the ropes of PCB design. For those still producing the FR4 equivalent of “Hello World”, it’s accomplishment enough that all the traces go where they’re supposed to. But eventually your designs will become more ambitious, and with this added complexity will naturally come new design considerations. For example, how do you keep a PCB from cooking itself in high current applications?
It’s this exact question that Mike Jouppi hoped to help answer when he hosted last week’s Hack Chat. It’s a topic he takes very seriously, enough that he actually started a company called Thermal Management LLC dedicated to helping engineers cope with PCB thermal design issues. He also chaired the development of IPC-2152, a standard for properly sizing board traces based on how much current they’ll need to carry. It isn’t the first standard that’s touched on the issue, but it’s certainly the most modern and comprehensive.
It’s common for many designers, who can be referencing data that in some cases dates back to the 1950s, to simply oversize their traces out of caution. Often this is based on concepts that Mike says his research has found to be inaccurate, such as the assumption that the inner traces of a PCB tend to run hotter than those on the outside. The new standard is designed to help designers avoid these potential pitfalls, though he notes that it’s still an imperfect analog for the real-world; additional data such as mounting configuration needs to be taken into consideration to get a better idea of a board’s thermal properties.
Even with such a complex topic, there’s some tips that are widely applicable enough to keep in mind. Mike says the thermal properties of the substrate are always going to be poor compared to copper, so using internal copper planes can help conduct heat through the board. When dealing with SMD parts that produce a lot of heat, large copper plated vias can be used to create a parallel thermal path.
Towards the end of the Chat, Thomas Shaddack chimes in with an interesting idea: since the resistance of a trace will increase as it gets hotter, could this be used to determine the temperature of internal PCB traces that would otherwise be difficult to measure? Mike says the concept is sound, though if you wanted to get an accurate read, you’d need to know the nominal resistance of the trace to calibrate against. Certainly something to keep in mind for the future, especially if you don’t have a thermal camera that would let you peer into a PCB’s inner layers.
A rig used to test thermal properties of different trace configurations.
While the Hack Chats are often rather informal, we noticed some fairly pointed questions this time around. Clearly there were folks out there with very specific issues that needed some assistance. It can be difficult to address all the nuances of a complex problem in a public chat, so in a few cases we know Mike directly reached out to attendees so he could talk them through the issues one-on-one.
While we can’t always promise you’ll get that kind of personalized service, we think it’s a testament to the unique networking opportunities available to those who take part in the Hack Chat, and thank Mike for going that extra mile to make sure everyone’s questions were answered to the best of his ability.
The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.
Join Hackaday Editor-in-Chief Elliot Williams and Assignments Editor Kristina Panos as we spend an hour or so dissecting some of the more righteous hacks and projects from the previous week. We’ll discuss a DIY TPM module that satisfies Windows 11, argue whether modern guts belong in retrocomputer builds even if it makes them more practical, and marvel at the various ways that sound has been encoded on film. We’ll also rock out to the idea of a 3D-printed guitar neck, map out some paths to defeating DYMO DRM, and admire a smart watch that has every sensor imaginable and lasts 36+ hours on a charge. Finally, we’ll sing the praises of RS-485 and talk about our tool collections that rival our own Dan Maloney’s catalogue of crimpers.
Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments below!
The Cyclops Blink botnet is thought to be the work of an Advanced Persistent Threat (APT) from Russia, and seems to be limited to Watchguard and Asus devices. The normal three and four letter agencies publicized their findings back in February, and urged everyone with potentially vulnerable devices to go through the steps to verify and disinfect them if needed. About a month later, in March, over half the botnet was still online and functioning, so law enforcement took a drastic step to disrupt the network. After reverse-engineering the malware itself, and getting a judge to sign off on the plan, the FBI remotely broke in to 13 of the Watchguard devices that were working as Command and Control nodes. They disinfected those nodes and closed the vulnerable ports, effectively knocking a very large chunk of the botnet offline.
The vulnerability in WatchGuard devices that facilitated the Botnet was CVE-2022-23176, a problem where an “exposed management access” allowed unprivileged users administrative access to the system. That vague description sounds like either a debugging interface that was accidentally included in production, or a flaw in the permission logic. Regardless, the problem was fixed in a May 2021 update, but not fully disclosed. Attackers apparently reversed engineered the fix, and used it to infect and form the botnet. The FBI informed WatchGuard in November 2021 that about 1% of their devices had been compromised. It took until February to publish remediation steps and get a CVE for the flaw.
This is definitely non-ideal behavior. More details and a CVE should have accompanied the fix back in May. As we’ve observed before, obscurity doesn’t actually prevent sophisticated actors from figuring out vulnerabilities, but it does make it harder for users and security professionals to do their jobs. Continue reading “This Week In Security: Vulnerable Boxes, Government Responses, And New Tools”→
Menopause is the time of life when menstrual periods come to a halt, and a woman is no longer able to bear children. The most obvious cause of menopause is when the ovaries run out of eggs, though it can also be caused by a variety of other medical processes. While menopause is in many ways well-understood, the biological reason for menopause, or the way in which it evolved in humanity remains a mystery. The process was once thought to be virtually non-existent in the animal kingdom, raising further questions.
Surprisingly recently, however, scientists began to learn that humans are not alone in this trait. Indeed, a small handful of sea-going mammals also go through this unique and puzzling process.
Scientists who work with animals love to track their movements. This can provide interesting insights on everything from mating behaviour, food sources, and even the way animals behave socially – or anti-socially, as the case may be.
This is normally achieved with the use of tracking devices, affixed to an animal so that it can be observed remotely while going about its normal business. However, Australian scientists have recently run into some issues in this area, as the very animals they try to track have been removing these very devices, revealing some thought-provoking behaviour in the process.
Honestly, I didn’t know I was a serial abuser of crimping tools until this weekend. I’ve been working on a small solar power system, and on Saturday I found myself struggling to get the BMS installed on the battery. I bought a Bluetooth dongle to connect the BMS to a smartphone app for checking the individual cells of the battery. I assumed it would just plug right into the UART port on the BMS, but alas — different connectors. So off I went to my bench, looking for a sensible way to make the connection.
My first thought was to simply log the connector off the dongle and solder the leads to the traces on the PCB right below the UART port. But then I saw that the pins in the port looked like 0.1″ pitch, so I rummaged through my stash to see what I could find. To my surprise, I had not only a kit of 0.1″ female crimps and housings, but I also had the crimping tool for them! I had no memory of making the purchase, but I thanked my lucky stars that I did, and got on with the job.
