Blue Ribbon Microphone

Edmund_Lowe_fsa_8b06653If you’ve ever seen an old movie or TV show where there was a radio announcer, you’ve probably seen a ribbon microphone. The RCA 44 (see Edmund Lowe, on right) had exceptional sound quality and are still valued today in certain applications. The name ribbon microphone is because the sound pickup is literally a thin strip of aluminum or other conductive material.

Unlike other common microphones, ribbons pick up high frequencies much better due to the high resonant frequency of the metallic ribbon. This is not only better in general, but it means the ribbon mic has a flatter frequency response even at lower frequencies. Another unique feature is that the microphone is bidirectional, hearing sounds from the front or back equally well. It is possible to build them with other directional patterns, although you rarely see that in practice.

Invention

In the early 1920s, Walter Schottky and Erwin Gerlach developed the ribbon microphone (and, coincidentally, the first ribbon loudspeaker). Harry Olson at RCA developed a ribbon mic that used coils and permanent magnets which led to the RCA Photophone Type PB-31 in 1931. Because of their superior audio response, they were instant hits and Radio City Music Hall started using the PB-31 in 1932. A newer version appeared in 1933, the 44A, which reduced reverberation.

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These 20 Projects Won $1000 In The Hackaday Prize

Since March, hundreds of hardware hackers around the globe have been hard at work designing and planning their entry into this year’s Hackaday Prize. The second challenge is now under way, a brand new chance for you to enter your own project. For inspiration, here are the top twenty entries from the first part of the Hackaday Prize.

The first challenge, Design Your Concept had 555 entries which we’ve spent the past week poring over. Now it’s time to reward the best of that first round with $1000 and a chance at winning the Hackaday Prize – $150,000 and a residency at the Supplyframe Design Lab in Pasadena.

The winners of Design Your Concept, in no particular order, are:

These twenty projects continue on to compete in the last phase of the Hackaday Prize. Congrats! Now get to work: you have a lot to do before the Hackaday Prize finals in October.

If your project didn’t make the cut – or you haven’t started one yet – don’t worry. Until the end of May we’re running the second challenge for this year’s Hackaday Prize. Anything Goes in this round and we’re looking for the craziest, most ostentatious, and most nonconformist project out there. Want to put the Internet of Socks on the blockchain? This challenge is right up your alley.

Anything Goes is a brand new challenge to solve a problem with technology and Build Something That Matters. Until the end of May, we’re opening up the gates for hackers, designers, and engineers to build whatever they want.

If you don’t have a project up on Hackaday.io, you can start one right now and submit it to The Hackaday Prize. If you already have a project up, add it to the Anything Goes challenge using the dropdown menu on the left sidebar of your project page.

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UV Photographic Printer Lets You Use Strange Chemistries

There is a family of old photographic chemistries based on iron compounds which, like the blueprint, are exposed using UV light. Ironically, the digital camera revolution which has made everything else in our photographic lives much easier, has made it harder to experiment around with these alternative methods. [David Brown] is making a UV photographic printer to change that.

[David]’s application has a lot in common with PCB printers that use a UV-sensitive resist, only [David] needs greyscale, and it might also be nice if it could work with wet paper. This makes it a more challenging project than you might think, but we like the cut of [David]’s jib.

Like some of the other UV exposer projects, [David]’s uses a rotating mirror to scan across the to-be photograph’s surface. Unlike the other ones that we’ve seen, the exposer hangs from two linear rails. Other printers move the paper underneath a stationary scanning head, which seems a mechanically simpler arrangement. We’re excited to see how this goes.

There’s a lot of interest in UV PCB printers right now. We’ve seen one made from junked CD-ROM drives on one end of the spectrum to one made by retrofitting a delta robot on the other. And don’t disregard the work done by folks interested in UV-curing 3D printers, either.

Debunking the Drone Versus Plane Hysteria

The mass media are funny in the way they deal with new technology. First it’s all “Wow, that’s Cool!”, then it’s “Ooh, that’s scary”, and finally it’s “BURN THE WITCH!”. Then a year or so later it’s part of normal life and they treat it as such. We’ve seen the same pattern repeated time and time again over the years.

The mass media tech story cycle. Our apologies to Gartner. Curve image: Jeremykemp [ CC BY-SA 3.0 ], via Wikimedia Commons
The mass media tech story cycle. Our apologies to Gartner. Curve image: Jeremykemp [ CC BY-SA 3.0 ], via Wikimedia Commons
Seasoned readers may remember silly stories in the papers claiming that the Soviets could somehow use the technology in Western 8-bit home computers for nefarious purposes, since then a myriad breathless exclusives have predicted a youth meltdown which never materialised as the inevitable result of computer gaming, and more recently groundless panics have erupted over 3D printing of gun parts. There might be a British flavour to the examples in this piece because that’s where it is being written, but it’s a universal phenomenon wherever in the world technologically clueless journalists are required to fill column inches on technical stories.

The latest piece of technology to feel the heat in this way is the multirotor. Popularly referred to as the drone, you will probably be most familiar with them as model-sized aircraft usually with four rotors. We have been fed a continuous stream of stories involving tales of near-misses between commercial aircraft and drones, and there is a subtext in the air that Something Must Be Done.

The catalyst for this piece is the recent story of a collision with a British Airways plane 1700ft over West London approaching London Heathrow. The ever-hyperbolic Daily Mail sets the tabloid tone for the story as a drone strike, while the BBC’s coverage is more measured and holds a handy list of links to near-miss reports from other recent incidents. This incident is notable in particular because a Government minister announced that it is now believed to have been caused by a plastic bag, and since there is already appropriate legislation there was little need for more. A rare piece of sense on a drone story from a politician. The multirotor community is awash with plastic bag jokes but this important twist did not seem to receive the same level of media attention as the original collision.

Are multirotors unfairly being given bad press? It certainly seems that way as the common thread among all the stories is a complete and utter lack of proof. But before we rush to their defence it’s worth taking a look at the recent stories and examining their credibility. After all if there really are a set of irresponsible owners flying into commercial aircraft then they should rightly be bought to book and it would do us no favours to defend them. So let’s examine each of those incident reports from that BBC story.

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Contender For World’s Most Unsettling Drone?

We’re not sure what FESTO is advertising with their odd flying beach ball. Amongst inspirational music it gently places its translucent appendage over a water bottle and then engulfs it with an unsettling plastic sound. With a high pitched whine it hovers away with its prey and deposits it in the hand of a thirsty business man, perhaps as a misguided nurturing instinct.

Despite discovering a new uncanny valley, the robot is pretty cool. It appears to a be a hybrid airship/helicopter on a small-scale. The balloon either zeros out the weight of the robot or provides slightly more lift. It’s up to the propellers to provide the rest.

We like the carbon fiber truss around the drone. It’s a really slick build with barely an untamed wire. This seems like a much safer design than a quadcopter for indoor flying. If its end effector wasn’t so creepy it would be even cooler. Video after the break.

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Software Update Destroys $286 Million Japanese Satellite

The Japanese X-ray telescope Hitomi has been declared lost after it disintegrated in orbit, torn apart when spinning out of control. The cause is still under investigation but early analysis points to bad data in a software package pushed shortly after an instrument probe was extended from the rear of the satellite. JAXA, the Japanese space agency, lost $286 million, three years of planned observations, and a possible additional 10 years of science research.

Hitomi, also known as ASTRO-H, successfully launched on February 17, 2016 but on March 26th catastrophe struck, leaving only pieces floating in space. JAXA, desperately worked to recover the satellite not knowing the extent of the failure. On April 28th they discontinued their efforts and are now working to determine the reasons for the failure, although a few weeks ago they did provide an analysis of the failure sequence at a press conference.

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Upgrading A 20 Year Old PDA

Before we had our iDevices and Androids, even before Blackberry, we had PDAs. The most famous of these mid-90s computing appliances are the Apple Newton and the Palm products, but the world of 90s PDAs was significantly more diverse than these two devices. Palm had a competitor in Handspring who released a cheaper and better version of a Palm OS device with the Visor. HP made hardware at one point, and you could run Windows – including Excel and Word – on a handheld device in 1998.

A company name Psion made PDAs with a clamshell design and a keyboard back then, too. Disregarding the operating system, these little clamshell PDAs could arguably be called the forerunners of yesterday’s netbooks and today’s Surface tablets. [RasmusB] is turning his Psion 5 PDA into something modern by replacing all the important bits while still keeping the clean design of this 20-year-old PDA.

The goal of this project is to completely replace the electronics of the Psion 5, while keeping all of the mechanics. That means the keyboard will stay the same, the device will run off of two AA batteries, and all the switches and ports will work. This effort began by making the Psion keyboard Arduino compatible by reverse engineering the keyboard matrix with a pencil and paper, and turning the keyboard into a USB keyboard.

Efforts to turn this Psion into a modern device are ongoing, but at least the outline of the main board is now in KiCad, with a microcontroller to decode the keyboard, switches for the lid and other buttons, and the correct space for the CompactFlash card and battery contacts. The next step is selecting a microprocessor and designing a circuit, but [Rasmus] is off to a great start to make this ancient PDA a modern computing device.

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