Sixteen Channel Retro Rotary Fader

April 1, 2021 by Chris Lott 3 Comments

Musician and electronic musical machine builder [Sam Battle] has recreated the unusual Crystal Palace Audio Fader over at Look Mum No Computer. The Crystal Palace was a rotary fader developed by engineer Dave Young at the BBC Radiophonic Workshop back in the late 1960s. Doctor Who fans might recognize it from the “The Krotons” series theme music. It’s a wild mechanical mixer, which fades between sixteen different inputs to produce its output by using a variable speed rotating pickup.

After Young built the prototype, three of these were made and put into cases cut out of scrap plexiglass) from a dumpster — hence they became known as Crystal Palaces after the 1851 glass and iron structure of the same name.

[Sam] decides to build this using some inductors and an old tape head. After proving out the concept on a breadboard, he mounts sixteen inductors on a 3D-printed circular frame. The rotating pickup transfers the signal via slip-rings at the top. An array of input jacks and level pots are mounted on the enclosure’s face plate, which contains a vector board full of op amps that drive the coils. Strictly speaking, the original fader used capacitive coupling, not inductive, but that doesn’t detract at all from this project. And as he states upfront, he intentionally didn’t dig too deep into the original, so as to put his own spin on the design.

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Econet – Britain’s Early Educational Network

April 16, 2020 by Al Williams 22 Comments

If you compare the early PC market for the US and the UK, you’ll notice one big difference. While many US schools had Apple computers, there were significant numbers of other computers in schools, as well. In the UK, pretty much every school that had a computer had an Acorn BBC Micro. [RetroBytes] takes us down memory lane, explaining how and why the schools went with Econet — an early network virtually unknown outside of the UK. You can see the video, which includes an interview with one of the Acorn engineers involved in Econet.

Nowadays, you don’t have to convince people of the value of a network, but back then it wasn’t a no brainer. The driver for most schools to adopt networking was to share a very expensive hard disk drive among computers. The network used RS-422, a common enough choice in Apple computers, spacecraft, and industrial control applications.

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DJI Fights Back Over Sensationalist Drone Reporting

July 7, 2019 by Jenny List 69 Comments

Over the past few years the number of reported near misses between multirotors, or drones as they are popularly referred to, and aircraft has been on the rise. While evidence to back up these reports has been absent time and again.

We’ve looked at incident reports, airport closures, and media reporting. The latest chapter comes in the form of a BBC documentary, “Britain’s Next Air Disaster? Drones” whose angle proved too sensational and one-sided for the drone manufacturing giant DJI. They have penned an acerbic open letter to the broadcaster (PDF link to the letter itself) that says that they will be launching an official complaint over the programme’s content. The letter begins with the following stinging critique:

As the world’s leader in civilian drones and aerial imaging technology, we feel it is our duty on behalf of the millions of responsible drone users around the globe, to express our deep disappointment at the BBC’s negative portrayal of drone technology and one-sided reporting based on hearsay.

It then goes on to attack the tone adopted by the presenter in more detail : “overwhelmingly negative, with the presenter frequently using the words ‘catastrophic’ and ‘terrifying’.“, before attacking the validity of a series of featured impact tests and highlighting the questionable basis for air proximity incident reports. They round the document off with a run through the safety features that they and other manufacturers are incorporating into their products.

DJI have pulled no punches in their condemnation of the standard of reporting on drone incidents in this document, and it is a welcome and rare sight in an arena in which the voices of people who know something of multirotors have been rather lonely and ignored. The BBC in turn have responded by saying “its investigation had shown positive uses of drones and that its programmes were fair“.

Over the past few years we have reported on this issue we have continually made the plea for a higher quality of reporting on drone stories. While Britain has been the center of reporting that skews negatively on the hobby, the topic is relevant wherever in the world there are nervous airspace regulators with an eye to any perceived menace. These incidents have pushed the industry to develop additional safety standards, as DJI mentions in their letter: “the drone industry itself has implemented various features to mitigate the risks described”. Let’s hope this first glimmer of a fight-back from an industry heavyweight (with more clout than the multirotor community) will bear the fruit of increased awareness from media, officials, and the general public.

If you’d like to see the BBC documentary in question it will be available for the next few weeks to people who see the Internet through a British IP address.

Thanks [Stuart] for the tip!

EF50: The Tube That Changed Everything

February 12, 2019 by Al Williams 32 Comments

From today’s perspective, vacuum tubes are pretty low tech. But for a while they were the pinnacle of high tech, and heavy research followed the promise shown by early vacuum tubes in transmission and computing. Indeed, as time progressed, tubes became very sophisticated and difficult to manufacture. After all, they were as ubiquitous as ICs are today, so it is hardly surprising that they got a lot of R&D.

Prior to 1938, for example, tubes were built as if they were light bulbs. As the demands on them grew more sophisticated, the traditional light bulb design wasn’t sufficient. For one, the wire leads’ parasitic inductance and capacitance would limit the use of the tube in high-frequency applications. Even the time it took electrons to get from one part of the tube to another was a bottleneck.

There were several attempts to speed tubes up, including RCA’s acorn tubes, lighthouse tubes, and Telefunken’s Stahlröhre designs. These generally tried to keep leads short and tubes small. The Philips company started attacking the problem in 1934 because they were anticipating demand for television receivers that would operate at higher frequencies.

Dr. Hans Jonker was the primary developer of the proposed solution and published his design in an internal technical note describing an all-glass tube that was easier to manufacture than other solutions. Now all they needed was an actual application. While they initially thought the killer app would be television, the E50 would end up helping the Allies win the war.

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The BBC Computer Literacy Project From The 1980s Is Yours To Browse

June 30, 2018 by Jenny List 12 Comments

In the early 1980s there was growing public awareness that the microcomputer revolution would have a significant effect on everybody’s lives, and there was a brief period in which anything remotely connected with a computer attracted an air of glamour and sophistication. Broadcasters wanted to get in on the act, and produced glowing documentaries on the new technology, enthusiastically crystal-ball-gazing as they did so.

In the UK, the public service BBC broadcaster produced a brace of series’ over the decade probing all corners of the subject as part of the same Computer Literacy Project that gave us Acorn’s BBC Micro, and we are lucky enough that they’ve put them all online so that we can watch them (again, in some cases, if a Hackaday scribe can get away with revealing her age).

You can see famous shows such as the moment when the presenters experienced a live on-air hack while demonstrating an early online service, but most of it is a fascinating contemporary look at the computers we now enthuse over as retro devices. Will the MSX sweep all before it, for example? (It didn’t).

They seem very dated now with their 8-bit micros (if not just for the word “micro”), synth music, and cheesy graphics. But what does come across is the air of optimism, this was the future, and it was packaged not as a threat, but as a good place to be. Take a look, but make sure you have plenty of time. You may spend a while in front of the screen.

We’ve mentioned int he past another spin-off from the Computer Literacy Project, the Domesday Project.

Thanks [Darren Grant] for the tip.

Rescuing K-9

June 13, 2018 by Jenny List 50 Comments

Fans of the long-running and ever-fantastic British TV show Dr. Who will no doubt hold a soft spot in their hearts for the Doctor’s little robot companion. No, not one of his many human sidekicks, we’re talking about K-9, the angular dog-like android that burst onto British screens back in 1977.

There were a number of original [K-9] props made by the BBC, and these were eventually sold by the corporation. One found its way to Abertay University, and it was there that [Gary Taylor], a computer science student found it. Sadly the years had not been kind to the robotic mutt, in particular water from a roof leak had damaged its internals beyond repair. With little more than the fibreglass shell to work with, he set out to rebuild K-9 and make the task the subject of his dissertation.

The original robo-dog was little more than a 1970s remote-controlled car, but its upgrades bring it firmly into the 21st century. At its heart is the inevitable Raspberry Pi 3, coupled with an Arduino mega 2560 that handles motor control and interfacing to an array of ultrasonic sensors. The Pi’s Bluetooth radio talks to an app on an Android phone, that serves as the K-9’s controller. All of which makes for an impressive upgrade, but we hope has disturbed as little of the original prop work as possible

Not everyone is lucky enough to find an original K-9, but for those destined for classic BBC prop disappointment there is always the possibility that you could build your own.

Hackaday Links: March 25, 2018

March 25, 2018 by Brian Benchoff 26 Comments

File this one under, ‘don’t do this yourself, but we’re glad they filmed it.’ [Denis Koryakin] flew a quadcopter to 10km, or about 33,000 feet. This was just an experiment to see if it was possible. A few items of note from the video: this thing was climbing at 14-15 m/s when it first took off. It was barely climbing at 2 m/s at 10km. Second: it was really, really cold. The ground temperature was -10 C, and temperatures at 8km reached -50 C. Density altitude is on this guy’s side, and I don’t know if this would be possible in warmer temperatures.

Hold on to your hats, there’s a gigantic space station that’s going to crash sometime in the next few weeks. Tiangong-1, an 8-ton space station launched in 2011, is going to reenter the atmosphere ‘sometime between March 30 and April 6’. Because of orbits and stuff, it’s more likely to reenter at the highest latitudes, and this space station has an inclination of 42.7 degrees. If your latitude is 42° N or 42° S, you should probably pull a Liza Minnelli on this situation and spend the next month in bed.

Hey, cool! The Tindie Badge is being used to teach orphans in Bosnia how to solder.

The BBC has decided to cancel Robot Wars. No, it’s not Battlebots — the house robots always seemed to be a bit overkill and added too much drama. No, it’s not Scrapheap Challenge or Junkyard Wars, but Robot Wars was legitimately fun, and cheap-to-produce reality TV. The engineering that went into these bots was amazing, and this is a loss for the entire engineering community. Here’s a change.org petition against its cancellation, but we all know how successful those change.org petitions can be.

FREE CHIPS!. Free motor drivers, actually, which is even more impressive. Aisler puts together BOMs for projects and such — think of it as an on-demand kitting service. They’re throwing in free Trinamic drivers with orders. Someone should build a motor driver breakout.