spectrum

57 Articles

Oh, Holey Light

September 30, 2020 by 18 Comments

We consider ourselves well-versed when it comes to the technical literature plastered on hardware store parts. Acronyms don’t frighten us, and our Google-fu is strong enough to overcome most mysteries. One bit of dark magic we didn’t understand was the gobbledygook on LED lamps. Wattage is easy and color temperature made sense because it corresponds with warm and cool colors, but Color Rendering Index (CRI) sounds like deep magic. Of course, some folks understand these terms so thoroughly that they can teach the rest of us, like [Jon] and [Kevin], who are building a light controller that corrects inadequacies in cheap lamps by installing several lamps into one unit.

We learned a lot by reading their logs, which are like the Cliff Notes from a lighting engineer’s textbook, but we’ll leave it as an exercise for the students to read through. Their project uses precise light sensors to measure the “flavor” of light coming off cheap lamps so you can mix up a pleasing ratio. In some ways, they are copying the effects of incandescent bulbs, which emit light relatively evenly across the visible light spectrum, right into the infrared. Unfortunately, cheap LEDs have holes in their spectrum coverage, and a Warm White unit has different gaps compared with Daylight, but combining them just right gives a rich output, without breaking the bank.

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DIY Radio Telescopes Hack Chat

February 10, 2020 by 8 Comments

Join us on Wednesday, February 12 at noon Pacific for the DIY Radio Telescopes Hack Chat with James Aguirre!

For most of history, astronomers were privy to the goings-on in the universe only in a very narrow slice of the electromagnetic spectrum. We had no idea that a vibrant and wondrous picture was being painted up and down the wavelengths, a portrait in radio waves of everything from nearly the moment of creation to the movement of galaxies. And all it took to listen in was an antenna and a radio receiver.

Over the years, radio telescopes have gotten more and more sophisticated and sensitive, and consequently bigger and bigger. We’re even to the point where one radio telescope often won’t cut it, and astronomers build arrays of telescopes spread over miles and miles, some with antennas that move around on rails. In the search for signals, radio astronomy has become the very definition of “Big Science.”

But radio astronomy doesn’t have to be big to be useful. James Aguirre, an astronomer at the University of Pennsylvania, spends his days (and nights) studying the radio universe with those big instruments. But he’s also passionate about down-scaling things and teaching everyone that small radio telescopes can be built on the cheap. His Mini Radio Telescope project uses a cast-off satellite TV dish and a couple of hundred bucks worth of readily available gear to scan the skies for all sorts of interesting phenomena.

Dr. Aguirre will join us on the Hack Chat to discuss all things radio astronomy, and how you can get in on the radio action on the cheap. Chances are good your junk pile — or your neighbor’s roof — has everything you need, and you might be surprised how approachable and engaging DIY radio astronomy can be.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 12 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about. Continue reading “DIY Radio Telescopes Hack Chat” →

Another IoT Debacle: Charter Offers Home Insecurity

January 18, 2020 by 38 Comments

If you are a glass-half-empty person, you’ll view Charter’s announcement that they will shutter their home security and smart home service on February 5th as another reason not to buy into closed-source IoT devices. If you are a glass-half-full person though, you’ll see the cable company’s announcement as a sign that a lot of Zigbee hardware will soon flood the surplus market. Ars Technica reports that after investigation it appears that some of the devices may connect to a standard Zigbee hub after a factory reset, but many others will definitely not.

As you might expect, users were less than thrilled. Especially those that shelled out thousands of dollars on sensors and cameras. This sort of thing might be expected if a company goes out of business, but Charter just doesn’t want to be in the home security business anymore.

Continue reading “Another IoT Debacle: Charter Offers Home Insecurity” →

Stick Your Own Samples In The Cheetah SpecDrum

May 21, 2019 by 10 Comments

The Sinclair ZX Spectrum was a popular computer in the 8-bit era, and particularly so in its homeland of the United Kingdom. It was known more for its low cost than its capabilities, but it gained many add-ons over the years. One of those was the Cheetah SpecDrum, which turned the Spectrum into a rudimentary drum machine. [PianoMatt] wasn’t happy with the original drum samples, so he set about loading a custom kit into the SpecDrum.

The SpecDrum software initially came with extra sample tapes, so [PianoMatt] knew it was an achievable task to load in custom samples. Starting by loading the software in an emulator, the RAM was then exported as raw data and loaded up in Audacity. After some experimentation, it was determined the samples were stored in 8-bit format at a sample rate of approximately 20 kHz. With this figured out, it was then possible to load replacement samples directly into RAM through the emulator.

However, this wasn’t enough for [PianoMatt]. Further digging enabled him to reverse engineer the format of the replacement sample tapes. Armed with this knowledge, [PianoMatt] then generated his own tape, complete with proper headers and labels for each drum sound.

It’s a tidy effort to bring a more modern sound to a now positively ancient piece of hardware. We’d love to hear a track with drums courtesy of the SpecDrum, so we’ll keep an ear out on Soundcloud. Mucking around with old sound hardware is a popular pastime in these parts – we’ve even seen people go so far as to build bespoke Sega chiptune players from scratch. 

How 5G Is Likely To Put Weather Forecasting At Risk

April 16, 2019 by 90 Comments

If the great Samuel Clemens were alive today, he might modify the famous meteorological quip often attributed to him to read, “Everyone complains about weather forecasts, but I can’t for the life of me see why!” In his day, weather forecasting was as much guesswork as anything else, reading the clouds and the winds to see what was likely to happen in the next few hours, and being wrong as often as right. Telegraphy and better instrumentation made forecasting more scientific and improved accuracy steadily over the decades, to the point where we now enjoy 10-day forecasts that are at least good for planning purposes and three-day outlooks that are right about 90% of the time.

What made this increase in accuracy possible is supercomputers running sophisticated weather modeling software. But models are only as good as the raw data that they use as input, and increasingly that data comes from on high. A constellation of satellites with extremely sensitive sensors watches the planet, detecting changes in winds and water vapor in near real-time. But if the people tasked with running these systems are to be believed, the quality of that data faces a mortal threat from an unlikely foe: the rollout of 5G cellular networks.

Continue reading “How 5G Is Likely To Put Weather Forecasting At Risk” →

Creating 8-bit Games With The Multi Platform Arcade Game Designer

March 29, 2019 by 8 Comments

Creating a game from scratch can be hard work. There are concepts to be designed, coding to be done, and art to be created to make it all happen. However, it doesn’t always have to be quite so difficult. There are a variety of development tools that allow budding game designers to get started with a point-and-click approach. [Jonathan Cauldwell] has come up with just such a tool that lets you do just that, for a variety of 8-bit platforms.

[Jonathan]’s project is called the Multi Platform Arcade Game Designer, so named for its ability to create games for several 8-bit systems of yesteryear. Currently, the Spectrum, Amstrad CPC, and Acorn Atom are all supported, with plans to add more down the track.

Creating a game is a simple affair, which [Jonathan] explores in a video tutorial series. Sprite and background editors are built into the software. Scripts can be automatically generated to create a wide variety of basic game types, from scrolling shoot-em-ups to classic platformers. There’s also functionality that allows advanced users to add further functionality by supplying some of their own code.

If point-and-click isn’t for you, you can always forge your ZX Spectrum games the classic way, with assembly and BASIC. Video after the break.

Continue reading “Creating 8-bit Games With The Multi Platform Arcade Game Designer” →

The Primordial Sinclair ZX Spectrum Emerges From The Cupboard

March 4, 2019 by 12 Comments

The Centre for Computing History in Cambridge, UK, receive many donations from which they can enrich their collection and museum displays. Many are interesting but mundane, but the subject of their latest video is far from that. The wire-wrapped prototype board they reveal with a flourish from beneath a folded antistatic mat is no ordinary computer, because it is the prototype Sinclair ZX Spectrum.

It came to the museum from Nine Tiles, a local consultancy firm that had been contracted by Sinclair Research in the early 1980s to produce the BASIC ROM that would run on the replacement for their popular ZX81 home microcomputer. The write-up and the video we’ve placed below the break give some detail on the history of the ROM project, the pressures from Sinclair’s legendary cost-cutting, and the decision to ship with an unfinished ROM version meaning that later peripherals had to carry shadow ROMs with updated routines.

The board itself is a standard wire-wrap protoboard with all the major Spectrum components there in some form.  This is a 16k model, there is no expansion connector, and the layout is back-to-front to that of the final machine. The ULA chip is a pre-production item in a ceramic package, and the keyboard is attached through a D connector. Decent quality key switches make a stark contrast to the rubber keys and membrane that Spectrum owners would later mash to pieces playing Daley Thompson’s Decathlon.

This machine is a remarkable artifact, and we should all be indebted to Nine Tiles for ensuring that it is preserved for those with an interest in computing to study and enjoy. It may not look like much, but that protoboard had a hand in launching a huge number of people’s careers in technology, and we suspect that some of those people will be Hackaday readers. We’ll certainly be dropping in to see it next time we’re in Cambridge.

If you haven’t been to the Centre for Computing History yet, we suggest you take a look at our review from a couple of years ago. And if prototype home computers are your thing, this certainly isn’t the first to grace these pages.

Continue reading “The Primordial Sinclair ZX Spectrum Emerges From The Cupboard” →