Author: Al Williams

4505 Articles

SSB In Your Pocket

August 22, 2022 by 66 Comments

In the old days, a shortwave radio was a major desk fixture. These days, you can get truly diminutive radios. However, most of them only have AM capability (that is, no simple way to receive single-sideband or SSB signals)  and — maybe — the ability to pick up FM broadcast.  Small radios also often have no provision for an external antenna which can be crucial for shortwave radios. [Farpoint Farms] shows off the Raddy RF7860 which is a palm-sided radio, but it has the elusive sideband modes and an external antenna port and wire antenna. It even has a rechargeable battery.

Reading the comments, it appears this is a rebadged version of a HanRongDa HRD 747 radio. Of course, there are other smaller radios with sideband reception like the Tecsun PL368, but they aren’t this small.  If you are in the market for a really tiny shortwave radio, this might be the thing for you.

Of course, the question is what you want to listen to on the shortwave bands these days. There are fewer and fewer broadcasters on shortwave, especially those that broadcast to a general audience. However, if there is something you want to hear, pairing this radio with a good portable antenna, would do the job.

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Better 3D Printing Via Chemistry?

August 21, 2022 by 8 Comments

If you have problems getting a 3D print to stick to the bed, you might consider using glue to — hopefully temporarily — attach the print to the bed. In addition, some plastics glue together well if you use a solvent. [Stefan] asks the question: What if you use solvent to glue each layer of a 3D print to the previous layer? The answer is in the video below.

If you know [Stefan], he is always meticulous, so the first test was with normal ABS parts. Then he used a solvent to glue two broken parts together to show how a single layer does with bonding.  Then he moved toward trying the solvent for each layer.

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Batteries Get Tiny

August 20, 2022 by 18 Comments

Steve Martin had a comedy routine that focused on the idea of “getting small.” That probably didn’t inspire the researchers at the Institute for Integrative Nanoscience when they set out to create a sub-square-millimeter microbattery. As you might expect, you won’t be starting your car with a battery the size of a grain of sand anytime soon, but these batteries do have a surprising capacity.

The key is creating what they call “micro-swiss rolls” where the electrodes are wrapped in a tiny cylinder. This isn’t a new idea. However, creating workable rolls at the scale where a grain of rice looks huge isn’t trivial.

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I’m Your Overlord, May I Take Your Order?

August 18, 2022 by 44 Comments

If you’ve ever been at an eatery and thought the server was a bit robotic, you should try San Francisco’s Mezli. The restaurant claims to be the first one to be totally automated. There are no humans in there. The restaurant serves Mediterranean grain bowls. Honestly, it is hard to decide if Mezli is a restaurant or a very sophisticated vending machine.

Then again, that makes sense. Only in science fiction do you have androids flying spaceships. In real life, the robot probably is the spaceship. Obviously, someone is still loading ingredients into the machine — some precooked — but that’s about it. Some restaurants let you order from a computer while a human makes your food and we’ve seen a few automated chefs, but nothing with this degree of mechanization.

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LCD Monitor Plays The Hits

August 18, 2022 by 1 Comment

In the old days, it wasn’t uncommon to put an AM radio near a computer or a monitor and deliberately cause interference to have a crude form of sound generation. Did you miss out on that? No! Thanks to [luambfb] you can now do the same trick with a common LCD monitor. You’ll need the horizontal refresh rate of the monitor in question.

Of course, doing it is somewhat less interesting than learning how it works. The effect relies on the fact that the LCDs emit signals as it refreshes a row. A black row emits relatively low energy while a white row emits more. Grayscale… well, you get the idea. Continue reading “LCD Monitor Plays The Hits” →

Chips Remembered: The Scenix/Ubicom/Parallax SX

August 17, 2022 by 70 Comments

If you are a bibliophile, going to a used bookstore is a distinctly pleasant experience. Sure, you might discover an old book that you want to read. But at least some of the endorphin rush comes from seeing old friends. Not humans, but books you read years or even decades ago. Most often, you don’t buy the book — you probably have one stashed in a box somewhere. But it is a happy feeling to see an old friend and maybe thumb through it reading a passage or two among shelves of musty books. I wish we had something like that for chips. Outside of a few notable exceptions, chips tend to have a short life span of popularity and then give way to other chips. This is especially true of CPUs. One that I especially miss is the Scenix/Ubicom/Parallax SX chip.

I had a bookstore-like experience with this processor the other day. I produced a few products based around these chips and I have a small stash of them left. I jealously guard the hardware needed to program them “just in case.” Well, naturally, someone needed a few for some reason so I had to dig it all up. Knowing these might be some of the last of the unprogrammed SX chips in the world made me a little nostalgic.

The Story

In the late 1990s, a company called Scenix started producing a microcontroller called the SX in a few footprint sizes. So the SX18 was, for example, an 18-pin part. By 1999, they were already in full swing with the SX18 and SX28 and they introduced the SX52.

Of course, a lot of companies produced microcontrollers. The Scenix offering was a bit special. In those days, the Microchip PIC was the king of the hill. The PIC is an odd beast that evolved from a very limited controller made to be small and inexpensive. Notably, while it could support relatively high clock frequencies — 20 MHz was common — each normal instruction took 4 clock cycles. So when your crystal said 20 MHz, you were running instructions at 5 MHz.

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What’s That Scope Trace Saying? UPD And Wireshark

August 14, 2022 by 9 Comments

[Matt Keeter], like many of us, has a lot of network-connected devices and an oscilloscope. He decided he wanted to look into what was on the network. While most of us might reach for Wireshark, he started at the PCB level. In particular, he had — or, rather, had someone — solder an active differential probe soldered into an Ethernet switch. The scope attached is a Textronix, but it didn’t have the analyzer to read network data. However, he was able to capture 190+ MB of data and wrote a simple parser to analyze the network data pulled from the switch.

The point of probing is between a network switch and the PHY that expands one encoded channel into four physical connections using QSGMII (quad serial gigabit media-independent interface). As the name implies, this jams four SGMII channels onto one pair.

As is common in networking schemes, the 8-bit byte is encoded into a 10-bit code group to ensure enough bit transitions to recover the synchronous clock. The decoding software has to examine the stream to find framing characters and then synchronize to the transmitted clock.

What follows is a nice tour of the protocol and the Python code to decode it. It seems complex, but the code is fairly short and also executes quickly. The output? Pcap files that you can process with Wireshark. Overall, a great piece of analysis. He also points out there are other tools already available to do this kind of decoding, but what fun is that?

Wireshark can do a lot of different kinds of analysis, even if you aren’t usually capturing from a scope. You can even decrypt SSL if you know the right keys.