Mechanical Image Acquisition With A Nipkow Disc

June 28, 2017 by Jenny List 36 Comments

If you mis-spent your teenage years fishing broken televisions from dumpsters and either robbing them for parts or fixing them for the ability to watch The A Team upstairs rather than in the living room as I did, then it’s possible that you too will have developed a keen interest in analogue television technology. You’ll know your front porch from your blanking interval and your colour burst, you might say.

An illustration of a simple Nipkow disk. Hzeller (CC BY-SA 3.0).

There was one piece of television technology that evaded a 1980s dumpster-diver, no 625-line PAL set from the 1970s was ever going to come close to the fascination of the earliest TV sets. Because instead of a CRT and its associated electronics, they featured a spinning disk with a spiral pattern of holes. These mechanical TV systems were quickly superseded in the 1930s by all-electronic systems, so of the very few sets manufactured only a fraction have survived the intervening decades.

The spinning disk in a mechanical TV is referred to as a Nipkow disk, after its inventor, [Paul Gottlieb Nipkow]. [Nipkow] conceived and patented the idea of a spinning disk with a spiral of holes to dissect an image sequentially into a series of lines in the 1880s, but without the benefit of the electronic amplification that would come a few decades later was unable to produce a viable system to demonstrate it. It would be in the 1920s before [John Logie Baird] would develop the first working television system using [Nipkow]’s invention.

Continue reading “Mechanical Image Acquisition With A Nipkow Disc” →

A Goldmine Of Radio Shack Goodies Is Up For Auction

June 24, 2017 by Jenny List 49 Comments

Where did you buy the parts for your first electronic project? That’s a question likely to prompt a misty-eyed orgy of reminiscences from many Hackaday readers, if ever we have heard one. The chances are that if you are from North America or substantial parts of the English-speaking world, you bought them from a store that was part of the Radio Shack empire. These modestly sized stores in your local mall or shopping centre carried a unique mix of consumer electronics, CB radio, computers, and electronic components, and particularly in the days before the World Wide Web were one of very few places in which an experimenter could buy such parts over the counter.

Sadly for fans of retail electronic component shopping, the company behind the Radio Shack stores faltered in the face of its new online competition over later years of the last decade, finally reaching bankruptcy in 2015. Gone are all but a few independently owned stores, and the brand survives as an online electronics retailer.

The glory days of Radio Shack may be long gone, but its remaining parts are still capable of turning up a few surprises. As part of the company’s archives they had retained a huge trove of Radio Shack products and memorabilia, and these have been put up for sale in an online auction.

There is such a range if items for sale that if you are like us you will probably find yourself browsing the listings for quite a while. Some of it is the paraphernalia of a corporate head-office, such as framed artwork, corporate logos, or strangely, portraits of [George W. Bush], but the bulk of the collection will be of more interest. There are catalogues galore from much of the company’s history, items from many of its promotions over the years including its ventures into sporting sponsorship, and numerous examples of Radio Shack products. You will find most of the computers, including a significant number of TRS-80s and accessories, tube-based radios and equipment from the 1950s, as well as cardboard boxes stuffed with more recent Realistic-branded items. There are even a few retail technology dead ends to be found, such as a box of :CueCat barcode readers that they evidently couldn’t give away back in the dotcom boom.

If you are interested in any of the Radio Shack lots, you have until the 3rd of July to snap up your personal piece of retail electronic history. Meanwhile if you are interested in the events that led to this moment, you can read our coverage of the retail chain’s demise.

Thanks [Mark Scott] for the tip.

Nominal Lumber Sizes Land Home Depot And Menards In Hot Water

June 23, 2017 by Jenny List 181 Comments

Hard times indeed must have fallen upon the lawyers of the American mid-west, for news reaches us of a possible class-action lawsuit filed in Chicago that stretches the bounds of what people in more gainful employment might consider actionable. It seems our legal eagles have a concern over the insufficient dimensions of their wood, and this in turn has caused them to apply for a class action against Home Depot and Menards with respect to their use of so-called nominal sizing in the sale of lumber.

If you have ever bought commercial lumber you will no doubt understand where this is going. The sawmill takes a piece of green wood straight from the forest, and cuts it to a particular size. It is then seasoned, either left to dry out and mature in the open air or placed in a kiln to achieve the same effect at a more rapid pace. This renders it into the workable lumber you expect to use, but causes a shrinkage of the wood that since it depends on variables such as moisture can not be accurately quantified. Thus a piece of wood cut by the sawmill at 4 inches square could produce a piece of seasoned lumber somewhere near 3.5 inches square. It would thus be sold as having only a nominal size of 4 inches This has been the case as long as commercial lumber has been produced, we’d guess for something in the region of a couple of centuries, and is thus unlikely to be a surprise to anyone in the market for lumber.

So, back to the prospective lawsuit. Once the hoots of laughter from the entire lumber, building, and woodworking industries have died down, is their contention that a customer being sold a material of dimension 3.5 inches as 4 inches is being defrauded a valid one? We are not lawyers here at Hackaday, but we’d expect the long-established nature of nominal lumber sizing to present a tough obstacle to their claim, as well as the existence of other nominally sized products in the building industry such as rolled steel joists. Is it uncharitable of us to characterise the whole escapade as a frivolous fishing exercise with the sole purpose of securing cash payouts? Probably not, and we hope the judges in front of whom this is likely to land agree with us.

If you have any thoughts on this case, especially if you have a legal background, we’d love to hear from you in the comments.

Sawn lumber image: By Bureau of Land Management (Oregon_BLM_Forestry_10) [CC BY 2.0].

Intel Discontinues Joule, Galileo, And Edison Product Lines

June 19, 2017 by Jenny List 195 Comments

Sometimes the end of a product’s production run is surrounded by publicity, a mix of a party atmosphere celebrating its impact either good or bad, and perhaps a tinge of regret at its passing. Think of the last rear-engined Volkswagens rolling off their South American production lines for an example.

Then again, there are the products that die with a whimper, their passing marked only by a barely visible press release in an obscure corner of the Internet. Such as this week’s discontinuances from Intel, in a series of PDFs lodged on a document management server announcing the end of their Galileo (PDF), Joule (PDF), and Edison (PDF) lines. The documents in turn set out a timetable for each of the boards, for now they are still available but the last will have shipped by the end of 2017.

It’s important to remember that this does not mark the end of the semiconductor giant’s forray into the world of IoT development boards, there is no announcement of the demise of their Curie chip, as found in the Arduino 101. But it does mark an ignominious end to their efforts over the past few years in bringing the full power of their x86 platforms to this particular market, the Curie is an extremely limited device in comparison to those being discontinued.

Will the departure of these products affect our community, other than those who have already invested in them? It’s true to say that they haven’t made the impression Intel might have hoped, over the years only a sprinkling of projects featuring them have come our way compared to the flood featuring an Arduino or a Raspberry Pi. They do seem to have found a niche though where there is a necessity for raw computing power rather than a simple microcontroller, so perhaps some of the legion of similarly powerful ARM boards will plug that gap.

So where did Intel get it wrong, how did what were on the face of it such promising products fizzle out in such a disappointing manner? Was the software support not up to scratch, were they too difficult to code for, or were they simply not competitively priced in a world of dirt-cheap boards from China? As always, the comments are open.

Header image: Mwilde2 [CC BY-SA 4.0].

Mixed Mode Bench PSU Delivers High Performance

June 18, 2017 by Jenny List 11 Comments

If you have an electronics bench, it follows that you will need some form of bench power supply. While many make do with fixed-voltage supplies it’s safe to say that the most useful bench power supplies have variable voltage and a variable current limiter. These are available in a range of sizes and qualities, and can be had from the usual online suppliers starting with a surprisingly small outlay.

There is however a problem with inexpensive bench power supplies. They are invariably switch-mode designs, and their output will often be noisy. Expensive linear supplies provide a much more noise-free output, but do so at the expense of excessive heat loss when regulating a high voltage drop.

One solution is a mixed-mode design, in which a switch-mode supply does the hard work of reducing the voltage most of the way, and a linear regulator drops the last couple of volts to provide a noise-free output. [Andrei] shows us his design for just such a mixed-mode supply, and it’s one you can have a go at building yourself.

His primary supply is an off-the-shelf switcher that turns mains AC into 24 V DC. This then feeds an LTC1624 buck converter that brings the voltage down to about 1.2 V above the final output voltage, this is in turn fed to a parallel pair of LT3081 linear regulators that deliver the final noise-free output. There is an INA260 for voltage and current measurement, and an Arduino with LCD display as a user interface. His prototype has been nicely constructed using a four-layer PCB, though he suggests it could be made on stripboard with the appropriate SMD adaptors. The cardboard chassis he’s used looks slightly alarming though.

We’ve covered numerous bench power supplies here over the years here at Hackaday. If it is an author’s favourite you are seeking though, take a look at the 723.

SHA 2017 Talk Schedule Revealed

June 16, 2017 by Jenny List 5 Comments

It’s always an exciting moment when an event schedule is released, and since events in our community don’t come much larger than this August’s SHA Camp in the Netherlands, you can imagine that the announcement of their schedule of lectures of talks is something of an event in itself. The event runs over five days, and you can browse the schedule itself to make your picks.

The SHA team have made their own picks, but with so many stages and speakers they are only a tiny selection. Running a Hackaday eye over the schedule, here are the ones that caught our eye.

[Kliment] has a workshop, Surface Mount Electronics Assembly for Terrified Beginners, in which you assemble a 20€ surface-mount power supply kit. [Editor’s Note: We’ve seen this one live — you can do it!]

[dennisdebel]’s lecture, from glass fiber to fiber glass noodles caught our eye. Using mung bean vermicelli, or ‘glass noodles’, for data transmission, is not something you hear about every day.

If you are a regular at European hardware hacker camps, you may have encountered the chiptune extravaganza performances of [Gasman], otherwise known as [Matt Westcott]. Hie lecture, Zero to chiptune in one hour, will create, from scratch, a chiptune cover version of a pop song chosen by the audience, all on a Sinclair ZX Spectrum.

The Hackeboy handheld game console is a project from a small Hamburg-based indie game label.[Axel Theilmann] describes the process of building the handheld console they always dreamed of.

One of the final lectures of the event comes from [Niek Blankers], and will describe in detail the SHA2017 badge. How it was designed, and showcasing what some of the attendees will by then have managed to do with it.

Finally, if you want to see a Hackaday scribe talking about fun and games with little plastic bags of parts, you could do worse than seeking out From Project To Kit, all you will need to know about turning your personal electronic projects into a kit business.

Watch this space for more from SHA Camp as we get it. Meanwhile you can take a look at our coverage of the SHA2017 badge launch.

Our Gunpowder And Tea Came From China, Why Didn’t We Copy Their Wheelbarrows?

June 13, 2017 by Jenny List 75 Comments

My dad's low-loader barrow. You would not believe how useful it is. — My dad’s low-loader barrow. You would not believe how useful it is.

Everyone must have a few things that are emotive of their childhood, perhaps a sight, a sound, or a smell. For me, growing up as I did on a small British organic farm in the 1970s, my emotive things are the smell of rain hitting parched earth, or of the slightly sulphurous diesel exhaust from a clapped-out Fordson Major tractor. And wheelbarrows, strangely. My dad, you see, is both a blacksmith by trade and an inveterate experimenter in the field of handcarts and barrows. A small self-sufficient farm generates a huge range of different loads that need carrying around, and he fashioned a variety of inventive contraptions for the purpose. Of most use are his oversized builder’s barrows with a full-size van wheel at the front and able to cross the bumpiest of ground, but other highlights included the low-loading barrow for shifting the heaviest one-piece loads, or the two-wheeler for very long objects.

As you might expect then, I have an eye for a barrow, as I’ve pushed a few in my time. So when I read about how traditional Chinese barrows are constructed, they caught my attention and I had to ask: why don’t we do it that way?

Continue reading “Our Gunpowder And Tea Came From China, Why Didn’t We Copy Their Wheelbarrows?” →