When it comes to the Internet of Things, many devices run off batteries, solar power, or other limited sources of electricity. This means that low power consumption is key to success. However, often these circuits draw relatively small currents that are difficult to measure, with plenty of transient current draw from their RF circuits. To effectively measure these low current draws, [Refik Hadzialic] built a cheap but accurate current probe.

The probe consists of a low value resistor of just 0.1 Ω, acting as a current shunt in series with the desired load. By measuring the voltage drop across this known resistor, it’s possible to calculate the current draw of the circuit.

However, the voltage drop is incredibly small for low current draws, so some amplification is needed. [Refik] does a great job of explaining his selection process, going deep into the maths involved to get the gain and part choice just right. The INA128P instrumentation amplifier from Texas Instruments was chosen, thanks to its good Common Mode Rejection Ratio (CMRR) and gain bandwidth.

The final circuit performs well, competing admirably with the popular uCurrent Gold measurement tool. While less feature-packed, [Refik]’s circuit appears to perform better in the noise stakes, likely due to the great CMRR rating of the TI part. It’s a great example of how the DIY approach can net solid results over and above simply buying something off the shelf.

Current sensing is a key skill to have in your toolbox, and can even help solve laundry disputes. Video after the break.

source https://hackaday.com/2020/07/27/a-low-cost-current-probe-for-iot-applications/

[splat238] needed a mask for going out in public, but wanted something that fit his personal style a bit better than the cloth masks everyone else was wearing. So, he upcycled his old airsoft mesh mask using an impressive 104 NeoPixels to create his NeoPixel LED Face Mask.

The NeoPixels are based on the popular WS2812b LEDs. These are individually addressable RGB LEDs with a pretty impressive glow. [splat238] purchased a 144 NeoPixel strip to avoid having to solder each of those 104 NeoPixels one-by-one. He cut the 144-LED strip into smaller segments to help fit the LEDs around the mask. He then soldered the power and data lines together so that he could still control the LEDs as if they were one strip and not the several segments he cut them into. He needed a pretty bulky battery pack to power the whole thing. You can imagine how much power 104 RGB LEDs would need to run. We recommend adding a battery protection circuit next time as these LEDs probably draw a hefty amount of current.

He designed his own controller board featuring an ESP8266 microcontroller. Given its sizable internal memory, the ESP8266 makes it easy to store a variety of LED patterns without worrying about running out of programming space. He’s also hoping to add some WiFi features in later revisions of his mask, so the ESP8266 is a no-brainer. Additionally, his controller board features three pushbuttons that allow him to toggle through different LED patterns on the fly.

Cool project [splat238]! Looking forward to the WiFi version.

source https://hackaday.com/2020/07/27/a-face-mask-thats-functional-and-hacker-certified/

We’ve been displaying numbers using segmented displays for almost 120 years now, an invention that predates the LEDs that usually power the ubiquitous devices by a half-dozen decades or so. But LEDs are far from the only way to run a seven-segment display — check out this mechanical seven-segment display for proof of that.

We’ve been seeing a lot of mechanical seven-segment displays lately, and when we first spotted [indoorgeek]’s build, we thought it would be a variation on the common “flip-dot” mechanism. But this one is different; to form each numeral, the necessary segments protrude from the face of the display slightly. Everything is 3D-printed from white filament, yielding a clean look when the retracted but casting a sharp shadow when extended. Each segment carries a small magnet on the back which snuggles up against the steel core of a custom-wound electromagnet, which repels the magnet when energized and extends the segment. We thought for sure it would be loud, but the video below shows that it’s really quiet.

While we like the subtle contrast of the display, it might not be enough for some users, especially where side-lighting is impractical. In that case, they might want to look at this earlier similar display and try contrasting colors on the sides of each segment.

source https://hackaday.com/2020/07/27/mechanical-seven-segment-display-really-sticks-out-from-the-pack/

If you’re planning to get into circuit sculpture one of these days, it would probably be best to start with something small and simple, instead of trying to make a crazy light-up spaceship or something with a lot of curves on the first go. A small form factor doesn’t necessarily mean it can’t also be useful. Why not start by making a small automatic night light?

The circuit itself is quite simple, especially because it uses an Arduino. You could accomplish the same thing with a 555, but that’s going to complicate the circuit sculpture part of things a bit. As long as the ambient light level coming in from the light-dependent resistor is low enough, then the two LEDs will be lit.

We love the frosted acrylic panels that [akshar1101] connected together with what looks like right angle header pins. If you wanted to expose the electronics, localize the light diffusion with a little acrylic cover that slips over the LEDs. Check it out in the demo after the break.

There’s more than one way to build a glowing cuboid night light. The Rubik’s way, for instance.

source https://hackaday.com/2020/07/27/tiny-circuit-sculpture-keeps-the-night-watch/

If you’re planning to get into circuit sculpture one of these days, it would probably be best to start with something small and simple, instead of trying to make a crazy light-up spaceship or something with a lot of curves on the first go. A small form factor doesn’t necessarily mean it can’t also be useful. Why not start by making a small automatic night light?

The circuit itself is quite simple, especially because it uses an Arduino. You could accomplish the same thing with a 555, but that’s going to complicate the circuit sculpture part of things a bit. As long as the ambient light level coming in from the light-dependent resistor is low enough, then the two LEDs will be lit.

We love the frosted acrylic panels that [akshar1101] connected together with what looks like right angle header pins. If you wanted to expose the electronics, localize the light diffusion with a little acrylic cover that slips over the LEDs. Check it out in the demo after the break.

There’s more than one way to build a glowing cuboid night light. The Rubik’s way, for instance.

source https://hackaday.com/2020/07/27/tiny-circuit-sculpture-keeps-the-night-watch/

If you live outside the UK you may not be familiar with Argos, but it’s basically what Americans would have if Sears hadn’t become a complete disaster after the Internet became popular. While they operate many brick-and-mortar stores and are a formidable online retailer, they still have a large physical catalog that is surprisingly popular. It’s so large, in fact, that interesting (and creepy) things can be done with it using machine learning.

This project from [Chris Johnson] is called the Book of Horrors and was made by feeding all 16,000 pages of the Argos catalog into a machine learning algorithm. The computer takes all of the pages and generates a model which ties the pages together into a series of animations that blends the whole catalog into one flowing, ever-changing catalog. It borders on creepy, both in visuals and in the fact that we can’t know exactly what computers are “thinking” when they generate these kinds of images.

The more steps the model was trained on the creepier the images became, too. To see more of the project you can follow it on Twitter where new images are released from time to time. It also reminds us a little of some other machine learning projects that have been used recently to create short films with equally mesmerizing imagery.

source https://hackaday.com/2020/07/26/argos-book-of-horrors/

Do you remember drawing your first schematic? Presumably you used a pen or a pencil and some kind of paper. Schematic capture software, though, makes it so much easier to draw schematics. There are many to choose from, but we spent some time checking out FidoCadJ and found it capable. Of course, there are many other options, but we did like that FidoCadJ runs locally and since it uses Java will run on just about any computer. Since it is open-source, you can modify it and you don’t have to worry about licensing it for your many computers or your team.

The program is a JAR file, and our first attempt to run it ran afoul of our older Java version that was the default Java Runtime Environment. But that was easy to fix, especially since a newer version was there, just not the default.

Java and PCs have come a long way, so the program is fast and responsive on a modern computer. There is a very nice library of components and PCB footprints plus other libraries available, so you could actually layout a PC board using the tool, although we wouldn’t suggest that.

The program can export to a number of formats, although we wish there was a bit more interoperability with other programs. It does create Eagle scripts and gEDA .pcb format files. We didn’t see an easy way to get those into KiCAD, for example, or even produce files for common autorouters However, that’s not really the project’s goals, either. According to their FAQ:

I already use Kicad, LTSpice, Cadence, Mentor, Altium or Visio, why is FidoCadJ interesting?

Because it is a different program pursuing different purposes. It is complementary with the big EDA electronic tools. Ever tried to include your schematics in a document or in a presentation? Were you happy of the result?

If you want to publish and share your drawings and you are not interested in the netlist features and simulation, FidoCadJ may be the tool for you. It is LaTeX-friendly: you can export drawings in a PGF/TikZ script to be included in your document.

Of course, both this program and KiCAD use ASCII files and the code is visible, so if you write a converter, let us know.

There are many ways to create schematics, of course. Even more so if you don’t mind the cloud.

source https://hackaday.com/2020/07/26/new-release-of-fidocadj-draws-schematics-everywhere/

An Australian teen is in hot water after he allegedly exposed sensitive medical information concerning COVID-19 patients being treated in a local hospital. While the authorities in Western Australia were quick to paint the unidentified teen as a malicious, balaclava-wearing hacker spending his idle days cracking into secure systems, a narrative local media were all too willing to parrot, reading down past the breathless headlines reveals the truth: the teen set up an SDR to receive unencrypted POCSAG pager data from a hospital, and built a web page to display it all in real-time. We’ve covered the use of unsecured pager networks in the medical profession before; this is a well-known problem that should not exactly take any infosec pros by surprise. Apparently authorities just hoped that nobody would spend $20 on an SDR and an afternoon putting it all together rather than address the real problem, and when found out they shifted the blame onto the kid.

Speaking of RF hacking, even though the 2020 HOPE Conference is going virtual, they’ll still be holding the RF Hacking Village. It’s not clear from the schedule how exactly that will happen; perhaps like this year’s GNU Radio Conference CTF Challenge, they’ll be distributing audio files for participants to decode. If someone attends HOPE, which starts this weekend, we’d love to hear a report on how the RF Village — and the Lockpicking Village and all the other attractions — are organized. Here’s hoping it’s as cool as DEFCON Safe Mode’s cassette tape mystery.

It looks like the Raspberry Pi family is about to get a big performance boost, with Eben Upton’s announcement that the upcoming Pi Compute Module 4 will hopefully support NVMe storage. The non-volatile memory express spec will allow speedy access to storage and make the many hacks Pi users use to increase access speed unnecessary. While the Compute Modules are targeted at embedded system designers, Upton also hinted that NVMe support might make it into the mainstream Pi line with a future Pi 4A.

Campfires on the sun? It sounds strange, but that’s what solar scientists are calling the bright spots revealed on our star’s surface by the newly commissioned ESA/NASA Solar Orbiter satellite. The orbiter recently returned its first images of the sun, which are extreme closeups of the roiling surface. They didn’t expect the first images, which are normally used to calibrate instruments and make sure everything is working, to reveal something new, but the (relatively) tiny bright spots are thought to be smaller versions of the larger solar flares we observe from Earth. There are some fascinating images coming back from the orbiter, and they’re well worth checking out.

And finally, although it’s an old article and has nothing to do with hacking, we stumbled upon Tim Urban’s look at the mathematics of human relations and found it fascinating enough to share. The gist is that everyone on the planet is related, and most of us are a lot more inbred than we would like to think, thanks to the exponential growth of everyone’s tree of ancestors. For example, you have 128 great-great-great-great-great-grandparents, who were probably alive in the early 1800s. That pool doubles in size with every generation you go back, until we eventually — sometime in the 1600s — have a pool of ancestors that exceeds the population of the planet at the time. This means that somewhere along the way, someone in your family tree was hanging out with someone else from a very nearby branch of the same tree. That union, likely between first or second cousins, produced the line that led to you. This is called pedigree collapse and it results in the pool of ancestors being greatly trimmed thanks to sharing grandparents. So the next time someone tells you they’re descended from 16th-century royalty, you can just tell them, “Oh yeah? Me too!” Probably.

source https://hackaday.com/2020/07/26/hackaday-links-july-26-2020/