Day: March 7, 2022

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.

Pop Goes The Mechanical Ping Pong Sculpture

March 7, 2022 by 12 Comments

In the waiting rooms of some dentists or doctors, you might have seen a giant metal ball rolling around in a large glass case. While it sure beats looking through those magazines, the sculpture can’t have come cheap. But not all of us want to pay high-end prices for fun toys. As a more cost-effective alternative, [JBV Creative] built an awesome 3D-printed ping pong sculpture.

The basic concept is the same as those fancy sculptures: a ball goes up, moves through some sort of impressive range of motion as it makes its way back down, and some sort of drive mechanism pushes it back to repeat the cycle anew. The design of this particular art piece is no different. A ping-pong ball falls down a funnel into a queue where balls are slowly loaded via a 12-way Geneva mechanism. An Archimedes spiral cam charges an elastic band that yeets the ball up and out of the track and sends it sailing through the air and down inside the funnel mentioned earlier. Everything on this sculpture is 3D-printed aside from the rubber bands and the ping pong balls.

What’s tricky about these sorts of things is the precision required both in printing and in design. It needs to run for hundreds if not thousands of hours and make no mistake. Making something work correctly 99% of the time is hard, but that last 1% can be almost as much work as that first 99%. [JBV Creative]’s first attempt had a catapult mechanism and he printed and tried out several scoops, but none gave the trajectory that he was looking for.

[JBV Creative] tried a plunger mechanism, but without a counterbalance weight providing the power, it just didn’t have enough oomph to launch the ball. Luckily, holes were included in the design, so it was relatively easy to adapt what had already been printed to use rubber bands instead. An additional goal was to have no visible fasteners, so everything needed to be mounted from the back. Check it out in action after the break.

It’s an incredible project that took serious thought, dedication, and in [JBV Creative]’s words, plenty of CAD twirling. It’s a great lesson in iterating and experimentation. If your talents are more soldering-based rather than CAD-based, perhaps a circuit sculpture is more up your alley?

Continue reading “Pop Goes The Mechanical Ping Pong Sculpture” →