FT8: Saving Ham Radio Or Killing It?

November 2, 2018 by 179 Comments

It is popular to blame new technology for killing things. The Internet killed newspapers. Video killed the radio star. Is FT8, a new digital technology, poised to kill off ham radio? The community seems evenly divided. In an online poll, 52% of people responding says FT8 is damaging ham radio.  But ham operator [K5SDR] has an excellent blog post about how he thinks FT8 is going to save ham radio instead.

If you already have an opinion, you have probably already raced down to the comments to share your thoughts. I’ll be honest, I think what we are seeing is a transformation of ham radio and like most transformations, it is probably both killing parts of ham radio and saving others. But if you are still here, let’s talk a little bit about what’s going on in ham radio right now and how it relates to the FT8 question. Oddly enough, our story starts with the strange lack of sunspots that we’ve been experiencing lately. Continue reading “FT8: Saving Ham Radio Or Killing It?” →

Flexible Battery Meter Bends Over Backward To Work

November 2, 2018 by 7 Comments

A lithium-ion battery tester seems like a simple project, at least electrically. But when you start thinking about the physical problem of dealing with a huge range of battery sizes, things get a little more complicated. Sure, you can 3D-print adapters and jigs to accommodate the different batteries, or you can cheat a bit and put the charger and tester circuit on a flexible PCB.

Maybe it’s the Kapton talking, but we really like the look of [Androkavo]’s project. The idea is simple – rather than use a rigid FR4 printed circuit board, a flexible polyimide film PCB a little longer than the biggest battery to be tested was fabricated. With large contacts on each end, the board can just be looped across the battery to take a reading. For charging, neodymium magnets on the other side of the board keep the charger in contact with the battery. The circuit itself is built around an STM8S003 8-bit microcontroller and a handful of discrete components. There’s a bar graph display for battery voltage that covers 2.0 to 4.9 volts, and a USB port for charging. The charger works with everything from the big 21700 cells down to the short 14500s. With the help of another magnet to keep the board from bending too sharply, even the diminutive 10180 can be charged. Check out the video below, which has some of the most relaxing music and best microscope shots of SMD soldering we’ve seen.

Flexible PCBs are versatile things. Not only can they make projects like this successful, but they can also wriggle around, swim, or even play music.

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The Linux Throwie: Powering A Linux Server With A 0.3W Solar Panel

November 2, 2018 by 63 Comments

Have you ever had one of those moments, when you’re rummaging through your spare parts heap, and have a rather bizarre project idea that you can’t quite get out of your head? You know, the ones that have no clear use, but simply demand to be born, of glass and steel and silicon?

This time, the stubborn idea in question was sort of like a solar-rechargeable LED throwie, but instead of a blinking light, it has a fully cloud-accessible embedded Linux server in the form of a Raspberry Pi 3 Model B+. Your choice of embedded Linux board should work — I just happen to have a lot of these due to a shipping error.

There were two main challenges here: First, it would have to combine the smallest practical combination of solar panel, power supply, and Li-ion cell that could run the Raspberry Pi. Second, we’ll need to remotely activate and access the Pi regardless of where it is, as well as be able to connect it to WiFi without direct physical access. In this article we’ll be dealing with the first set of problems — stay tuned for the rest.

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Cooking Eggs With Magnets In Motion

November 2, 2018 by 71 Comments

It’s probably always going to be easier to just find some dry wood and make a cooking fire, but if you’re ever in a real bind and just happen to have a bunch of magnets and a treadmill motor, this DIY induction cooktop could be your key to a hot breakfast.

For those not familiar with them, induction cooktops are a real thing. The idea stretches all the way back to the turn of the last century, and involves using a strong magnetic field to induce eddy currents in the metal of a cooking vessel. As [K&J Magnetics] explains, the eddy currents are induced in a conductor by changing magnetic fields nearby. The currents create their own magnetic field which opposes the magnetic field that created it. The resulting current flows through the conductor, heating it up. For their cooktop, they chose to spin a bunch of powerful neodymium magnets with alternating polarity using an old treadmill motor. The first try heated up enough to just barely cook an egg. Adding more magnets resulted in more heat, but the breakthrough came with a smaller pan. The video below shows the cooktop in action.

It’s worth noting that commercial induction cooktops use coils and a high-frequency alternating current instead or rotating magnets. They also are notoriously fussy about cookware, too. So, kudos to [K&J] for finding success with such an expedient build. As a next step, we’d love to see the permanent magnets replaced with small coils that can be electrically commutated, perhaps with a brushless motor controller. Continue reading “Cooking Eggs With Magnets In Motion” →

SMORES Robot Finds Its Own Way To The Campfire

November 2, 2018 by 2 Comments

Robots that can dynamically reconfigure themselves to adapt to their environments offer a promising advantage over their less dynamic cousins. Researchers have been working through all the challenges of realizing that potential: hardware, software, and all the interactions in between. On the software end of the spectrum, a team at University of Pennsylvania’s ModLab has been working on a robot that can autonomously choose a configuration to best fit its task at hand.

We’ve recently done an overview of modular robots, and we noted that coordination and control are persistent challenges in this area. The robot in this particular demonstration is a hybrid: a fixed core module serving as central command, plus six of the lab’s dynamic SMORES-EP modules. The core module has a RGB+Depth camera for awareness of its environment. A separate downwards-looking camera watches SMORES modules for awareness of itself.

Combining that data using a mix of open robot research software and new machine specific code, this team’s creation autonomously navigates an unfamiliar test environment. While it can adapt to specific terrain challenges like a wood staircase, there are still limitations on situations it can handle. Kudos to the researchers for honestly showing and explaining how the robot can get stuck on a ground seam, instead of editing that gaffe out to cover it up.

While this robot isn’t the completely decentralized modular robot system some are aiming for, it would be a mistake to dismiss based on that criticism alone. At the very least, it is an instructive step on the journey offering a tradeoff that’s useful on its own merits. And perhaps this hybrid approach will find application with a modular robot close to our hearts: Dtto, the winner of our 2016 Hackaday Prize.

[via Science News]

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Cut Through The Noise, See Tiny Signals

November 1, 2018 by 18 Comments

An oscilloscope is a handy tool for measuring signals of all kinds, but it’s especially useful if you want to measure something with a periodic component. Modern oscilloscopes have all kinds of features built-in that allow you sample a wide range of signals in the hundreds of megahertz, and make finding and measuring your signal pretty easy, provided you know which buttons to push. There are some advanced oscilloscope methods that go beyond the built-in features of even the best oscilloscopes, and [AM] has a tutorial on one of them.

The method used here is called phase-senstitive detection, and allows tiny signals to be found within noise, even if the magnitude of the noise is hundreds of times greater than the signal itself. Normally this wouldn’t be possible, but by shifting the signal out of the DC range and giving it some frequency content, and then using a second channel on the oscilloscope to measure the frequency content of the source and triggering the oscilloscope on the second channel, the phase of the measured signal can be sifted out of the noise and shown clearly on the screen.

In [AM]’s example, he is measuring the intensity of a laser using a photodiode with a crude amplifier, but even with the amplifier it’s hard to see the signal in the noise. By adding a PWM-like signal to the power source of the laser and then syncing it up with the incoming signal from the photodiode, he can tease out the information he needs. It’s eally a fascinating concept, and if you fancy yourself a whiz with an oscilloscope this is really a tool you should have in your back pocket.  If you’re new to this equipment, we do have a primer on some oscilloscope basics, too.

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Code Review Lamp Subtly Reminds You To Help Your Fellow Developer

November 1, 2018 by 10 Comments

[Dimitris Platis] works in an environment with a peer review process for accepting code changes. Code reviews generally are a good thing. One downside though, is that a lack of responsiveness from other developers can result in a big hit to team’s development speed. It isn’t that other developers are unwilling to do the reviews, it’s more that individuals are often absorbed in their own work and notification emails are easily missed. There is also a bit of a “tragedy of the commons” vibe to the situation, where it’s easy to feel that someone else will surely attend to the situation, but often no one does. To combat this, [Dimitris] built this Code Review Lamp, a subtle notification that aims to prod reviewers into action.

The lamp is based on a ring of RGB LEDs and a Wemos D1 Mini board. The Wemos utilizes the popular ESP8266, so it’s easy to develop for. The LED ring and Wemos are tied together with a slick custom PCB. Mounting the LED ring on the top of the PCB and the Wemos on the bottom allows for easy powering via a USB cable while directing light upward.  The assembly is placed in a translucent 3D printed enclosure creating a pleasant diffuse light source.

Every developer gets a Code Review Lamp. The lamps automatically log in to the change management system to check whether anything is awaiting review. If a review is ready, the Lamp glows in a color specific to the individual developer. All this serves as a gentle but persistent reminder that someone’s work is being held up until a review is completed.

We love the way that the device has a clear purpose: it does its job without any unnecessary features or parts. It’s similar to this ESP8266 IoT Motion Sensor in that it has a single job to do, and focuses on it well.

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