A Classic Shortwave Radio Restored

November 12, 2023 by Al Williams 20 Comments

Before the Internet, if you wanted to hear news from around the world, you probably bought a shortwave receiver. In the golden age of world band radio, there was a great deal of high-quality programming on the shortwave bands and a large variety of consumer radios with shortwave bands. For example, the Sony CRF-160 that [M Caldeira] is restoring dates from the late 1960s or early 1970s and would have been a cool radio in its day. It retailed for about $250 in 1972, which sounds reasonable, but — don’t forget — in 1972 that would have been a 10% downpayment on a new car or enough to buy a Big Mac every day for a year with change left over.

As you can see in the video below, the radio seemed to work well right out of the gate, but the radio needed some rust removal and other sprucing up. However, it is an excellent teardown, with some tips about general restoration.

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Leaky SMD Electrolytics? Try These Brute Force Removal Methods

November 12, 2023 by Dan Maloney 25 Comments

When you say “recapping” it conjures up an image of a dusty old chassis with point-to-point wiring with a bunch of dried-out old capacitors or dodgy-looking electrolytics that need replacement. But time marches on, and we’re now at the point where recapping just might mean removing SMD electrolytics from a densely packed PCB. What do you do then?

[This Does Not Compute]’s answer to that question is to try a bunch of different techniques and see what works best, and the results may surprise you. Removal of SMD electrolytic caps can be challenging; the big aluminum can sucks a lot of heat away, the leads are usually pretty far apart and partially obscured by the plastic base, and they’re usually stuffed in with a lot of other components, most of which you don’t want to bother. [TDNC] previously used a hot-air rework station and liberally applied Kapton tape and aluminum foil to direct the heat, but that’s tedious and time-consuming. Plus, electrolytics sometimes swell up when heated, expelling their corrosive contents on the PCB in the process.

As brutish as it sounds, the solution might just be as simple as ripping caps off with pliers. This seems extreme, and with agree that the risk of tearing off the pads is pretty high. But then again, both methods seemed to work pretty well, and on multiple boards too. There’s a catch, though — the pliers method works best on caps that have already leaked enough of their electrolyte to weaken the solder joints. Twisting healthier caps off a PCB is likely to end in misery. That’s where brutal method number two comes in: hacking the can off the base with a pair of flush cutters. Once the bulk of the cap is gone, getting the leads off the pad is a simple desoldering job; just don’t forget to clean any released schmoo off the board — and your cutters!

To be fair, [This Does Not Compute] never seems to have really warmed up to destructive removal, so he invested in a pair of hot tweezers for the job, which works really well. But perhaps you’re not sure that you should just reflexively replace old electrolytics on sight. If so, you’re in pretty good company.

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Ham Radio Memes In The 1970s

November 11, 2023 by Al Williams 12 Comments

If you have a fondness for old and unusual ham gear, [Saveitforparts] has a great video (see below) about a Robot slow scan receiver he found at a junk store. Slow scan or SSTV is a way to send pictures via low-bandwidth audio, such as you often find on the ham bands. The idea is you take a picture, send some squeaks and blips over the air, and in about 8 or 10 seconds, a single frame of video shows up at the receiver. Hams aren’t the only ones who used it. The Apollo missions used an SSTV system in some cases, too.

I’ve been a ham radio operator for a very long time. When I first heard about SSTV, I thought it sounded cool that you could be talking to someone and then show them a picture of your station or your dog or your kids. But when I looked into it, the reality was far different. In the pre-internet days, SSTV-equipped hams hung out on a handful of watering hole frequencies and basically just sent memes and selfies to each other. Everyone would take turns, but there wasn’t really any conversation.

This actually still goes on, but the hardware isn’t a big deal anymore. The Robot in the video had to decode the signal from audio and store the image somehow. On old gear — some of it homebrew — it was simply persistent phosphor that would eventually fade, but, of course, eventually, images were stored in some form of digital memory. These days, you are likely to use a PC soundcard to both send and receive the necessary audio.

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Pimp The Potentiometer

November 11, 2023 by Al Williams 23 Comments

Sometimes, a hack isn’t really about the technology but about the logistics. If we asked you to light up an LED using an Arduino, there’s a good chance you’d know exactly how to do that. How about a bunch of LEDs? Simple. Now turn on LEDs proportional to an input voltage. A little harder, but nothing that you probably haven’t done a million times. Finally, arrange the LEDs in an attractive circle around a potentiometer. Wait, how are you going to do that? [Upir] shows us a ready-made ring light for just this purpose and you can see the beautiful thing in the video below.

We made the LED things sound slightly easier than it is. The ring light has 31 LEDs but only 12 pins, so there is some multiplexing going on. The modules come in pairs for about $20, so not a throwaway part, but they will really dress up anything that needs a knob of any kind.

Naturally, it doesn’t matter what you use to drive the LEDs. You could track a pot or a rotary encoder. Or you could show microphone levels or something else. After all, it is just a bunch of LEDs. For that matter, they’d probably make a good pair of robot eyes. Let us know what you want to use them for in the comments.

If your significant other is a little geeky, you might want a different kind of ring light. We couldn’t help but wish the LEDs on the ring were addressable. That would open up a world of interesting possibilities while reducing the pin count, too.

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Hands On With Boondock Echo

November 10, 2023 by Dan Maloney 23 Comments

Perhaps no words fill me with more dread than, “I hear there’s something going around.” In my experience, you hear this when some nasty bug has worked its way into the community and people start getting whatever it is. I’m always on my guard when I hear about something like this, especially when it’s something really unpleasant like norovirus. Forewarned is forearmed, after all.

Since I work from home and rarely get out, one of the principal ways I keep apprised of what’s going on with public health in my community is by listening to my scanner radio. I have the local fire rescue frequencies programmed in, and if “there’s something going around,” I usually find out about it there first; after a half-dozen or so calls for people complaining of nausea and vomiting, you get the idea it’s best to hunker down for a while.

I manage to stay reasonably well-informed in this way, but it’s not like I can listen to my scanner every minute of the day. That’s why I was really excited when my friend Mark Hughes started a project he called Boondock Echo, which aims to change the two-way radio communications user experience by enabling internet-backed recording and playback. It sounded like the perfect system for me — something that would let my scanner work for me, instead of the other way around. And so when Mark asked me to participate in the beta test, I jumped at the chance.

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Hackaday Podcast 243: Supercon, Super Printing, And Super Gyros

November 10, 2023 by Al Williams No comments

With solder fumes from Supercon still in the air, Hackaday’s Elliot Williams and Al Williams met to compare notes about the conference talks, badge hacking, and more. Tom Nardi dropped by, too.

Did you miss Supercon? It isn’t quite the whole experience, but most of the talks are on our YouTube channel, with more coming in the weeks ahead. Check out the live tab for most of the ones up now. You can even watch the badge hacking celebration. We’ll be writing up more in the following weeks.

Al nailed What’s That Sound, as did many others, except Elliot. [Jacx] gets a T-shirt, and you get a chance to play again next week.

The hacks this week range from a pair of posts pertaining to poop — multi-color 3D printer poop, that is. We wondered if you could print rainbow filament instead of a purge tower. The Raspberry Pi 5 draws a lot of excess power when in standby. Turns out, thanks to the Internet, the easy fix for that is already in. Other hacks range from EMI test gear to portable antennas with excursions into AI, biomedical sensors, and retrocomputing.

In the Can’t Miss category, we discussed Maya Posch’s post, which could just as easily be titled: Everything You Ever Wanted to Know about CAT Cable (But Were Afraid to Ask). Last, but not least, you’ll hear about Lewin Day’s round up of exotic gyroscope technology, including some very cool laser pictures.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download for listening or for a very long ringtone.

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Fastest Semiconductor May Also Be Most Expensive

November 9, 2023 by Al Williams 26 Comments

Scientists have found what they think may be the fastest known semiconductor. Sounds great, right? But it happens to made from one of the rarest elements: rhenium. That rare element combines with selenium and chlorine to form a “superatom.” Unlike conventional semiconductor material, the superatom causes phonons to bind together and resist scattering. This should allow materials that can process signals in femtoseconds,

Rhenium was the last stable element to be found in 1925. It is primarily used in combination with nickel in parts of jet engines, although it is also known as a catalyst for certain reactions. It is very rare and has a high melting point, exceeded only by tungsten and carbon. When it was discovered, scientists extracted a single gram of the material by processing 660 kg of molybdenite. Because of its rarity, it is expensive, costing anywhere from $2,800 to $10,600 per kilogram.

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