Author: Jenny List

3312 Articles

The Last Few Analogue TV Stations In North America

January 29, 2021 by 40 Comments

Analogue TV is something that most of us consider to have been consigned to the history books about a decade ago depending on where in the world we are, as stations made the transition to much more power and frequency efficient digital multiplexes. However some of them still cling on for North American viewers, and [Antenna Man] took a trip to Upstate New York in search of some of them before their final switch-off date later this year.

What he reveals can be seen in the video below the break, an odd world of a few relatively low-power analogue TV stations still serving tiny audiences, as well as stations that only exist because their sound carrier can be picked up at the bottom of the FM dial. These stations transmit patterns or static photographs, with their income derived from the sound channel’s position as an FM radio station. While his journey is an entertaining glimpse into snowy-picture nostalgia it does also touch on some other aspects of the aftermath of analogue TV boradcasting. The so-called “FrankenFM” stations sound much quieter, we’re guessing because of the lower sound carrier deviation of the CCIR System M TV spec compared to regular FM radio. And we’re told that there are more stations remaining in Canada, so get out there if you still want to see an analogue picture before they’re gone forever. Where this is being written the switch to DVB was completed in 2013, and it’s still a source of regret that we didn’t stay up to see the final closedown.

Does your country still have an analogue TV service? Tell us in the comments.

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A Look At The Interesting RP2040 Peripheral, Those PIOs

January 29, 2021 by 41 Comments

The Raspberry Pi Pico is the latest product in the Raspberry Pi range, and it marks a departure from their previous small Linux-capable boards. The little microcontroller board will surely do well in the Pi Foundation’s core markets, but its RP2040 chip must have something special as a commercial component to avoid being simply another take on an ARM microcontroller that happens to be a bit more expensive and from an unproven manufacturer in the world of chips. Perhaps that special something comes in its on-board Programmable IO peripherals, or PIOs. [CNX Software] have taken an in-depth look at them, which makes for interesting reading.

The PIOs are a set of state machines that have their own simple assembly language to execute simple repetitive I/O tasks without requiring the attention of the main processor core. How they can be configured is up to the imagination of the programmer, but examples suggested are extra I2C or SPI buses, or video interfaces. We expect the hacker community to push them to extremes with unexpected applications, much as has happened with the ESP32’s I2S peripheral. The article introduces the assembly language, then gives us simple examples in assembler, C/C++, and Python. If you have a Raspberry Pi Pico then you’ll surely be wanting to have a play with the PIOs, and we look forward to seeing what you come up with.

You can read Hackaday’s review of the Pico here.

The Politics Of Supersonic Flight: The Concord(e)

January 25, 2021 by 29 Comments

Every nation has icons of national pride: a sports star, a space mission, or a piece of architecture. Usually they encapsulate a country’s spirit, so citizens can look up from their dreary lives and say “Now there‘s something I can take pride in!”  Concorde, the supersonic airliner beloved by the late 20th century elite for their Atlantic crossings, was a genuine bona-fide British engineering icon.

But this icon is unique as symbols of national pride go, because we share it with the French. For every British Airways Concorde that plied the Atlantic from London, there was another doing the same from Paris, and for every British designed or built Concorde component there was another with a French pedigree. This unexpected international collaboration gave us the world’s most successful supersonic airliner, and given the political manoeuverings that surrounded its gestation, the fact that it made it to the skies at all is something of a minor miracle. Continue reading “The Politics Of Supersonic Flight: The Concord(e)” →

No More Cows: Iconic 1990s Download Site Finally Shuttered By Tucows

January 24, 2021 by 28 Comments

In the early and mid 1990s there were a host of big players in the nascent public Internet that played their part in guiding the adventurous early Web users on their way. Many of them such as Netscape or Altavista have fallen by the wayside, while players such as Lycos and Yahoo are still in existence but shadows of their former selves. Some other companies broadened their businesses to become profitable and still exist quietly getting on with whatever they do. An example is Tucows, now a major domain name registrar, who have finally announced the closure of their software library that was such an essential destination in those times.

The company name was originally an acronym: “The Ultimate Collection Of Winsock Software”, started in 1993 by a library employee in Flint, Michigan. As its name suggests it was a collection of mostly shareware Windows software, and the “Winsock” refers to Windows Sockets, the API used by Windows versions of the day for accessing network resources. It seems odd to modern eyes, but connecting a 486 PC running Windows 3.1 to the Internet was something of a complex process without any of the built-in software we take for granted today. Meanwhile the fledgling Linux distributions were only for the extremely tech-savvy or adventurous, so the world of open-source software had yet to make a significant impact on consumer-level devices.

The passing of a Windows shareware library would not normally be a story of interest, but it is the part that Tucows played in providing a reliable software source on the early Web  that makes it worthy of note. It’s something of a shock to discover that it had survived into the 2020s, it’s been so long since it was relevant, but if you sat bathed in the glow of a CRT monitor as you waited interminably for your CuteFTP download over your 28.8k modem to finish then you probably have a space for Tucows somewhere in your heart. If you fancy a trip down memory lane, the Internet Archive have a very period-ugly-looking version of the site from 1996.

You may no longer have a 486 on your desk, but if you want to you can still build one.

What Makes A Good Antenna?

January 24, 2021 by 13 Comments

It sometimes seems as though antennas and RF design are portrayed as something of a Black Art, the exclusive preserve of an initiated group of RF mystics and beyond the reach of mere mortals. In fact though they have their difficult moments it’s possible to gain an understanding of the topic, and making that start is the subject of a video from [Andreas Spiess]. Entitled “How To Build A Good Antenna”, it uses the design and set-up of a simple quarter-wave groundplane antenna as a handle to introduce the viewer to the key topics.

What makes this video a good one is its focus on the practical rather than the theoretical. We get advice on connectors and antenna materials, and we’re introduced to the maths through online calculators rather than extensive formulae. Of course the full calculations are there to be learned by those with an interest, but for many constructors they can be somewhat daunting. We’re shown a NanoVNA as a useful tool in the antenna builder’s arsenal, one which gives a revolutionary window on performance compared to the trial-and-error of previous times. Even the ground plane gets the treatment, with its effect on impedance and gain explored and the emergence of its angle as a crucial factor in performance. We think this approach does an effective job of breaking the mystique surrounding antennas, and we hope it will encourage viewers to experiment further.

If your appetite has been whetted, how about taking a look at a Nano VNA in action?

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Your NES Classic Mini Controller, On Your Desktop Computer

January 24, 2021 by 7 Comments

The NES Classic Mini was one of the earlier releases in what became a wider trend for tiny versions of classic retro consoles to be released. Everybody wanted one but numbers were limited, so only the lucky few gained this chance to relive their childhood through the medium of Donkey Kong or Mario Brothers on real Nintendo hardware. Evidently [Albert Gonzalez] was one of them, because he’s produced a USB adapter for the Mini controller to allow it to be used as a PC peripheral.

On the small protoboard is the Nintendo connector at one end, an ATtiny85 microcontroller, and a micro-USB connector at the other. The I2C interface from the controller is mapped to USB on the ATtiny through the magic of the V-USB library, appearing to the latter as a generic gamepad. It’s thought that the same interface is likely to also work with the later SNES Classic Mini controller. For the curious all the code and other resources can be found in a GitHub repository, so should you have been lucky enough to lay your hands on a NES Classic Mini then you too can join the PC fun.

The mini consoles were popular, but didn’t excite our community as much as could be expected. Our colleague Lewin Day tool a look at the phenomenon last summer.

An Alternator Powered Electric Bicycle Gives Rotor Magnetic Field Insight

January 24, 2021 by 63 Comments

For anyone involved in the construction of small electric vehicles it has become a matter of great interest that a cheap high-power electric motor can be made from a humble car alternator. It’s a conversion made possible by the advent of affordable three-phase motor controllers, and it’s well showcased by [austiwawa]’s electric bicycle build video (embedded below).

The bike itself is a straightforward conversion in which the motor powers the rear wheel via an extra sprocket. He tried a centrifugal clutch with limited success, but removed it for the final version. Where the interest lies in this build is in his examination of Hall effect sensor placement.

Most alternator conversions work without sensors, though for better control it’s worth adding these magnetic sensors to allow the controller to more directly sense the rotation. He initially placed them at the top of the stator coils and found them to be ineffectual, with the big discovery coming when he looked at the rotor. The electromagnet in the rotor on a car alternator has triangular poles with the field concentrated in the centre of the stator, thus a move of the sensors to half way down the stator solved the problem. Something to note, for anyone converting an alternator.

Should you wish to give it a try, a year ago we published a primer on turning car parts into motors.

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