A Nostalgic Look At A Kid’s Shortwave Receiver

July 18, 2024 by 10 Comments

[Mikrowave1] had a Unelco shortwave receiver as a kid. This was a typical simple radio for the 1960s using germanium and silicon transistors. It also had plug-in coils you had to insert into sockets depending on the frequency band you wanted to receive.

While simple AM radios were all the rage, they didn’t have to operate at higher frequencies. [Mikrowave1] shows some of the design tricks used to allow the radio to operate in the upper part of the spectrum. Otherwise, the radio is the usual superhet design using lower frequency germanium PNP transistors in the IF stage. You get a look inside the radio and a peek at a similar schematic along with notes on where the radio is different.

But how does it work? For an old single-conversion receiver, it works well enough. Of course, when the radio was new, there were many more interesting stations on shortwave. Today, he had to settle for some ham radio stations and CHU, the Canadian time and frequency station.

There were six pairs of coils built on top of tube sockets. The coil was actually more than a coil. There were other components in the case that adjusted other radio parameters based on the frequency.

[Mikrowave1] has been on a toy kick lately, and we’ve enjoyed it. This radio looks simple compared to the Radio Shack one that every kid wanted in the 1970s. Well. Every hacker kid, at least.

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Smart Ball Technology Has Reached Football, But The Euros Show Us It’s Not Necessarily For The Better

July 16, 2024 by 56 Comments
Adidas brought smart balls to Euro 2024, for better or worse. Credit: Adidas

The good old fashioned game of football used to be a simple affair. Two teams of eleven, plus a few subs, who were all wrangled by a referee and a couple of helpful linesmen. Long ago, these disparate groups lived together in harmony. Then, everything changed when VAR attacked.

Suddenly, technology was being used to adjudicate all kinds of decisions, and fans were cheering or in uproar depending on how the hammer fell. That’s only become more prevalent in recent times, with smart balls the latest controversial addition to the world game. With their starring role in the Euro 2024 championship more than evident, let’s take a look at what’s going on with this new generation of intelligent footballs.

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Iron Man Arc Reactor Clock Is A Stylish Piece

July 12, 2024 by 4 Comments

Iron Man was the film that kicked off the Marvel craze, and is widely regarded to be better than a lot of the movies that followed. If you’re a big fan of the OG, you’re probably already drowning in Iron Man helmets and arc reactor doo-dads, but here’s one more for you. After all, you probably don’t have an arc reactor clock yet.

The build comes to us from [jerome95]. It starts with an off-the-shelf ring of addressable LEDs, which serves as the basic defining dimension for the project. The ring gets a 3D printed support structure and some non-functional copper coils to complete the basic “arc reactor” look. Inside the center sits a small 7-segment display which displays the time under the command of an ESP32. It uses a network time server so it’s always on the dot.  Meanwhile, if you’re not a fan of the 7-segment version, you can always try the OLED variant of the build instead.

It’s not a complicated build; that could have been easily achieved, though. The builder could have displayed the time by making the LEDs flash different colors, instead of using a 7-segment display. However, that would have made a far more confounding clock. As it is, this design would make an excellent gift for any Marvel fan. Particularly those that acknowledge the supremacy of the film that started it all.

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A 1940s Car Radio Receives Some Love

June 13, 2024 by 9 Comments

The entertainment systems in modern vehicles is akin to a small in-dash computer, and handles all manner of digital content. It probably also incorporates a radio, but increasingly that’s treated as something of an afterthought. There was a time though when any radio in a car was a big deal, and if you own a car from that era it’s possible that you’ve had to coax an aged radio into life. [The Radio Mechanic] is working on a radio from a 1946 Packard, which provides a feast for anyone with a penchant for 1940s electronics.

The unit, manufactured by Philco, is an all-in-one, with a bulky speaker in the chassis alongside the tubes and other components. It would have sat behind the dash in the original car, so some external cosmetic damage is not critical. Less easy to pass off is the cone rubbing on the magnet, probably due to water damage over the last eight decades. Particularly interesting are the controls, as we’re rather enamored with the multicolored filter attached to the tone control. A laser cutter makes short work of recreating the original felt gasket here.

The video below is the first of a series on this radio, so we don’t see it working. Ahead will be a lot more cleaning up and testing of components, and we’d expect a lot of those paper capacitors to need replacement. We can almost smell that warm phenolic smell.

If tube radio work is your thing, we’ve been there before.

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The Pi Pico, An SDR Receiver Front End

June 5, 2024 by 22 Comments

Making a software defined radio (SDR) receiver is a relatively straightforward process, given the right radio front end electronics and analogue-to-digital converters. Two separate data streams are generated using clocks at a 90 degree phase shift, and these are passed to the software signal processing for demodulation. But what happens if you lack a pair of radio front ends and a suitable clock generator? Along comes [Mordae] with an SDR using only the hardware on a Raspberry Pi Pico. The result is a fascinating piece of lateral thinking, extracting something from the hardware that it was never designed to do.

The onboard RP2040 ADC is of course far too slow for the task, so instead an input is used, with a negative feedback arrangement from another GPIO to form a crude 1-bit ADC. A PIO peripheral is then used to perform the quadrature mixing, resulting in the requisite pair of data streams. At this point these are sent over USB to GNU Radio for demodulating, mainly for convenience rather than necessarily because the microcontroller lacks the power.

The result is a working SDR front end, demonstrated pulling in an FM broadcast station. The Pico has to be overclocked to reach that frequency and it’s more than a little noisy, but we’re extremely impressed with how much has been done with so little. Oddly it isn’t the first Pico SDR we’ve seen, but the previous one was a much more conventional and lower-frequency affair for the European Long Wave band.

Tell Time And Predict The Heavens With This Astronomical Timepiece

May 31, 2024 by 2 Comments

Looking for a new project, or just want to admire some serious mechanical intricacy? Check out [illusionmanager]’s Astronomical Clock which not only tells time, but shows the the positions of the planets in our solar system, the times of sunrise and sunset, the phases of the moon, and more — including solar and lunar eclipses.

One might assume that the inside of the Astronomical Clock is stuffed with a considerable number of custom gears, but this is not so. The clock’s workings rely on a series of tabs on movable rings that interact with each other to allow careful positioning of each element. After all, intricate results don’t necessarily require complex gearing. The astrolabe, for example, did its work with only a few moving parts.

The Astronomical Clock’s mechanical elements are driven by a single stepper motor, and the only gear is the one that interfaces the motor shaft to the rest of the device. An ESP32-C3 microcontroller takes care of everything else, and every day it updates the position of each element as well as displaying the correct time on the large dial on the base.

The video below shows the clock in operation. Curious its inner workings? You can see the entire construction process from beginning to end, too.

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This WiFi Filament Sensor Is Unnecessary, But Awesome

May 19, 2024 by 3 Comments

As desktop 3D printers have inched towards something resembling the mainstream, manufacturers have upped their game across the board. Even the quality of filament that you can get today is far better than what was on the market in the olden days, back when a printer made out of laser-cut birch wasn’t an uncommon sight at the local makerspace. Now, even the cheap rolls are wound fairly well and are of a consistent diameter. For most folks, you just need to pick a well-reviewed brand, buy a roll, and get printing.

But as with everything else, there are exceptions. Some people are producing their own filaments, or want to make sure their extrusion rate is perfectly calibrated. For those that need the capability, the WInFiDEL from [Sasa Karanovic] can detect filament diameter in real-time while keeping the cost and complexity as low as possible. Even better, with both the hardware and software released as open source, it makes an excellent starting point for further development and customization.

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