Data Science The Stanford Way

November 12, 2023 by Al Williams 27 Comments

Data science is a relatively new term for a relatively old discipline. Essentially, it is data analysis, particularly for large data sets. It involves techniques as wide-ranging as statistics, computer science, and information theory. What to know more? Stanford has a “Data Science Handbook” that you can read online.

Topics range from how to design a study and create an analytic plan to how to do data visualization, summarization, and analysis. The document covers quite a bit but is very concise.

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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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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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Roll Your Own Python Debugger

November 11, 2023 by Al Williams 10 Comments

Debugging might be the one thing that separates “modern” programming from “classic” programming. If you are on an old enough computer — or maybe one that has limited tools like some microcontrollers — debugging is largely an intellectual exercise. Try a program, observe its behavior, and then try again. You can liberally sprinkle print statements around if you have an output device or turn on LEDs or digital outputs if you don’t. But with a debugger, you can get a bird’s-eye view of your program’s data and execution flow.

For some languages, writing a debugger can be hard — you usually use at least some system facility to get started. But as [mostlynerdness] shows, Python’s interpreter wants to help you create your own debugger, and you can follow along to see how it’s done. This is accessible because Python has a built-in debugging core that you can use and extend. Well, regular Python, that is. MicroPython has some low-level support, and while we’ve seen attempts to add more, we haven’t tried it.

Of course, you may never need to build your own debugger — most of the IDEs have already done this for you, and some of the code is, in fact, lifted from an open code base and simplified. However, understanding how the debugging plumbing works may give you a leg up if you need to create custom logic to trap an error that would be difficult to find with a generic debugger. Plus, it is just darn interesting.

Like many Python things, there are some version sensitivities. The post is in four parts, with the last two dealing with newer API changes.

We can’t promise that Python can debug your hardware, though. We always thought the C preprocessor was subject to abuse, but it turns out that Python has the same problem.

Wind Tunnel Uses The Last Straw

November 10, 2023 by Al Williams 14 Comments

If you watch the movies, there isn’t much to a wind tunnel. Just a fan and a tunnel, right? The truth is there’s a lot more to it than that, and [ejs13] shows you how you can make a small tunnel with some basic supplies. One of the requirements for a useful tunnel is to have laminar flow — that is, flow in uniform layers with little, if any, mixing. This tunnel achieves laminar flow using an array of soda straws to direct the flow. In fact, there are 150 straws in total. You can see a short clip of the wind tunnel in action below.

The rest of the parts are easy, too. A computer fan provides wind, and there’s a little bit of wood and acrylic. You’ll notice in the video that you can easily see the airflow. That’s thanks to a light source, some water, and a bit of dry ice.

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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.