RFM9x module held in an adapter board with flexipins

FlexyPins Might Help With Those Pesky Castellated Modules

March 7, 2022 by 49 Comments

[SolderParty] just announced FlexyPins (Twitter, alternative view) – bent springy clips that let you connect modules with castellated pins. With such clips, you can quickly connect and disconnect any castellated module, swapping them without soldering as you’re prototyping, testing things out, or pre-flashing modules before assembly. They’re reportedly gold-plated, and a pack of ~100 will set you back 6EUR, shipping not included.

Of course, this is basically “fancy pieces of wire”, purpose-shaped, gold-plated and, hopefully, made out of material that is springy enough and doesn’t snap easily after bending a few times. We’ve seen this concept used for prototyping before, with random pieces of wire doing a pretty good job of maintaining connectivity, but these clips bring it that much closer to production-grade. It also makes us wonder – just how hard it is to solder 30-40 of them into a circuit? Do they self-align enough with the footprints given, or do you have to hold them with tweezers at a peculiar angle as you solder them? Time will tell, of course.

Continue reading “FlexyPins Might Help With Those Pesky Castellated Modules” →

A Variable Capacitor For Not A Lot

March 7, 2022 by 35 Comments

There’s one component which used to be ubiquitous in every experimenter’s junk box, but nowadays unless you happen to be a radio amateur the chances are you may not have seen one in a long time, if ever. We’re talking of course about the air-dielectric variable capacitor, the tuning element for millions of radio receivers back in the day but now long ago replaced by much flimsier polymer-dielectric parts. There’s still a need for variable capacitors though, in particular a high-voltage variant for use in magnetic loop antennas. It’s something that [Ben] had a need for, which he solved with a clever combination of PCB material and 3D printing.

While the variable capacitors of yore invariably used intersecting vanes on a rotor, this one has two large parallel plates that intersect as one is moved over the other with a lead screw. It’s cheap and effective, and best of all, the files to make it can be downloaded from Thingiverse. He claims a 34pF-164pF capacitance range, which, looking at the size of the plates we find to be believable (and which is a useful range for most HF applications). We like this solution, and believe it makes more sense than being scalped for an older example at a radio rally.

This isn’t the first variable capacitor we’ve shown you, though some previous examples have been more conventional.

Top side of the VL670 breakout board, with two USB connectors and the VL670 chip in the center.

A Chip To Bridge The USB 2 – USB 3 Divide

March 7, 2022 by 34 Comments

On Twitter, [whitequark] has  found and highlighted an intriguing design – a breakout board for the VL670, accompanied by an extensive yet very easy to digest write-up about its usefulness and inner workings. The VL670 is a chip that addresses a surprising problem – converting USB 2.0 signals into USB 3.0.

If you have a USB 2.0 device and a host with only USB 3.0 signals available, this chip is for you. It might be puzzling – why is this even needed? It’s about the little-known dark secret of USB3, that anyone can deduce if they ever have to deal with a 9-pin USB 3.0 connector where one of the three differential pairs doesn’t quite make contact.

When you see a blue “3.0” port, it’s actually USB 2 and USB 3 — two separate interfaces joined into a single connector. USB 3 uses two single-directional differential pairs, akin to PCI-E, whereas USB 2 uses a single bidirectional one, and the two interfaces on a blue connector operate basically independently of each other. There’s many implications to this that are counterintuitive if you simply take “USB 3.0” for “faster backwards-compatible USB”, and they have painful consequences.

For instance, USB 3 hub ICs have two separate hub entities inside – one for USB 3 and one for USB 2. Even if you have a USB 3 hub plugged into a USB 3 port, multiple USB 2 devices plugged into it still cannot break through the USB 2 uplink limit of 480 MBps. If you ever thought that a faster hub with a faster uplink would fix your USB 2 device speed problems – USB-IF engineers, apparently, thought differently; and you might have to find a workaround for your “many cheap SDRs and Pi 4 in a box” setup. Continue reading “A Chip To Bridge The USB 2 – USB 3 Divide” →

Metal 3D Printing Hack Chat

March 7, 2022 by 1 Comment

Join us on Wednesday, March 9 at noon Pacific for the Metal 3D Printing Hack Chat with Agustin Cruz!

3D printing has been an enabling technology, and the ability to create parts that never existed anywhere before has been a real game-changer. But the cheap and readily accessible FDM and SLA printers we’ve come to depend on are not without their drawbacks, chief among which is that they only make plastic parts. Wouldn’t it be great if we home-gamers had the ability to print metal parts just like they do in industry? Agustin Cruz thinks so, and he’s been hard at work on an electron-beam sintering printer to make that dream come true. Dealing with the technical challenges of such a printer hasn’t been easy, but then again, squeezing out melted plastic wasn’t easy at first either.

join-hack-chatAgustin has agreed to take a little time out of his project to talk to us about his progress, and to share what he has learned about electron-beam printing. Along the way, we’ll talk about metal printing in general, and perhaps even take a look at where the whole field is going and how — and when — it’ll penetrate the hobby printing market.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 9 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.
Continue reading “Metal 3D Printing Hack Chat” →

USB Temperature Logger With Some Extra Tricks

March 7, 2022 by 5 Comments

Many of us electronics hacker types tend to have at least the same common equipment on our benches, namely a multimeter, an oscilloscope, some sort of adjustable power supply, and maybe a logic analyzer. These are great tools covering many bases, but dealing with temperature measurements is often neglected. A sudden need for such often results in just buying a either dedicated measurement unit, or some cheap eBay thermocouple board and just rolling with a few hacks. [Jana Marie Hemsing] had a need for measuring the thermal side of things, and got fed up with hacking with piles of boards, and designed herself a proper instrument for the task.

The result is a very tidy four-channel thermocouple frontend, feeding the data into the host computer via USB. Each of the four channels can either be a K-type input or a NTC thermistor input, decided at board assembly time, but you could just build two units with four channels of each and cover all bases. The K-type thermocouple input is based around the MAX31855 series device. While the ‘KASA’ suffixed device is probably most common, if you need to dedicate some channels to handling one of the other six or so other common thermocouple types, that just needs the appropriate MAX31855 variant dropping in, and you’re good to go.

For the controller, [Jana] has chosen the common STM32F0x microcontroller, which handles all the USB protocol side of things. The extra functionality added allows direct driving of a heater controller via the DRV8837 H-Bridge, with a extra few open collector outputs for other things you might want to drive. This allows the logger to function as a kind-of thermal IO device. Firmware is written in good old fashioned STM32 HAL, using the standard STM32CubeMX and the GCC toolchain. It looks like the Makefile came via the STM32 Project Generator route. The firmware has a neat trick up its sleeve too; with a flick of the switch on the back, the firmware can switch between outputting CSV data over a standard USB CDC link (a virtual serial port), or it can present a SCPI terminal interface, enabling integration into existing SCPI-based test flows. Nice work!

We’ve seen a few logging projects on these fair pages, like this battery powered ESP32 logger device. If IoT logging is more your thing, here you go.

The Invisible Battlefields Of The Russia-Ukraine War

March 7, 2022 by 27 Comments

Early in the morning of February 24th, Dr. Jeffrey Lewis, a professor at California’s Middlebury Institute of International Studies watched Russia’s invasion of Ukraine unfold in realtime with troop movements overlaid atop high-resolution satellite imagery. This wasn’t privileged information — anybody with an internet connection could access it, if they knew where to look. He was watching a traffic jam on Google Maps slowly inch towards and across the Russia-Ukraine border.

As he watched the invasion begin along with the rest of the world, another, less-visible facet of the emerging war was beginning to unfold on an ill-defined online battlefield. Digital espionage, social media and online surveillance have become indispensable instruments in the tool chest of a modern army, and both sides of the conflict have been putting these tools to use. Combined with civilian access to information unlike the world has ever seen before, this promises to be a war like no other.

Modern Cyberwarfare

The first casualties in the online component of the war have been websites. Two weeks ago, before the invasion began en masse, Russian cyberwarfare agents launched distributed denial of service (DDoS) attacks against Ukrainian government and financial websites. Subsequent attacks have temporarily downed the websites of Ukraine’s Security Service, Ministry of Foreign Affairs, and government. A DDoS attack is a relatively straightforward way to quickly take a server offline. A network of internet-connected devices, either owned by the aggressor or infected with malware, floods a target with request, as if millions of users hit “refresh” on the same website at the same time, repeatedly. The goal is to overwhelm the server such that it isn’t able to keep up and stops replying to legitimate requests, like a user trying to access a website. Russia denied involvement with the attacks, but US and UK intelligence services have evidence they believe implicates Moscow. Continue reading “The Invisible Battlefields Of The Russia-Ukraine War” →

Greedy Receivers: FCC Considers Regulating Receivers After Altimeter Showdown

March 7, 2022 by 94 Comments

Recently, the media was filled with articles about how turning on 5G transmissions in the C-band could make US planes fall out of the sky. While the matter was ultimately resolved without too much fuss, this conflict may have some long-term consequences, with the FCC looking to potentially address and regulate the root of the problem, as reported by Ars Technica.

At the heart of the whole issue is that while transmitters are regulated in terms of their power and which part of the spectrum they broadcast on, receivers are much less regulated. This means that in the case of the altimeters in airplanes for example, which use the 4.2 GHz – 4.4 GHz spectrum, some of their receivers may be sensitive to a part of the 5G C-band (3.7 GHz -3.98 GHz), despite the standard 200 MHz guard band (upped to 400 MHz in the US) between said C-band and the spectrum used by altimeters.

What the FCC is currently doing is to solicit ways in which it could regulate the performance and standards for receivers. This would then presumably not just pertain to 5G and altimeters, but also to other receivers outside of avionics. Since the FCC already did something similar back in 2003 with an inquiry, but closed it back in 2007 without any action taken, it remains to be seen whether this time will be different. One solid reason would be the wasted spectrum: a 400 MHz guard band is a very large chunk.

Thanks to [Chris Muncy] for the tip.