Author: Jenny List

3250 Articles

It’s An Audio Distortion Analyzer, Just Not The One You Were Hoping For

December 19, 2023 by 7 Comments

An audio distortion analyzer is a specialist piece of analogue test equipment that usually costs a lot of money and can be hard to track down on the second hand market. Finding one is a moment of luck for the average engineer then, but [Thomas Scherrer OZ2CPU]’s discovery isn’t quite what he might have hoped for. Nonetheless, his Bang and Olufsen K3 Distortion meter DM1 from 1979 is still an interesting and high quality piece of test equipment, and the video below the break makes for a worthwhile watch.

Bang and Olufsen are best known for high-end design Hi-Fi units, thus it’s a surprise to find that in the past they also manufactured test equipment. This distortion meter isn’t a general purpose one, instead it’s designed to measure tape recorders in particular, and it uses an elegant technique. Instead of injecting a sine wave and removing it from what comes out in order to measure the products of the distortion, it records a 333 Hz sine wave onto a tape, then measures the strength of its 3rd harmonic at 1 kHz as an indication of distortion. It’s a working distortion meter made with clever analogue circuitry for a fraction of the cost of the more conventional models that HP would have sold you at the same time, even if it doesn’t give the same THD figure you might have been looking for.

If distortion interests you, it’s a subject we’ve looked at in the past.

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When Is An Engineer Not An Engineer? When He’s A Canadian Engineer

December 18, 2023 by 218 Comments

In medieval Europe, many professions were under the control of guilds. These had a monopoly over that profession in their particular city or state, backed up with all the legal power of the monarch. If you weren’t in the guild you couldn’t practice your craft. Except in a few ossified forms they are a thing of the past, but we have to wonder whether that particular message ever reached Western Canada.

An electoral candidate with an engineering degree who practices what any sane person would call engineering, has been ordered by a judge to cease calling himself an engineer. The heinous crime committed by the candidate, one [David Hilderman], is to not be a member of the guild Association of Professional Engineers and Geoscientists of B.C. We get it that maybe calling a garbage truck driver a waste collection engineer may be stretching it a little, but here in the 21st century we think the Canadian professional body should be ashamed of themselves over this case. Way to encourage people into the engineering profession!

Here at Hackaday, quite a few of us writers are engineers. Stepping outside our normal third person, I, [Jenny List], am among them. My electronic engineering degree may be a little moth-eaten, but I have practiced my craft over several decades without ever being a member of the British IEE. No offence meant to the IEE, but there is very little indeed they have to offer me. If the same is true in Canada to the extent that they have to rely on legal sanctions to protect their membership lists, then we think perhaps the problem is with them rather than Canadian engineers. You have to ask, just how is an engineering graduate who’s not a guild member supposed to describe themselves? Some of us need to know, in case we ever find ourselves on holiday in Canada!

Header: Joe Gratz, CC0.

Mickey Shall Be Free!

December 18, 2023 by 24 Comments

The end of the year brings with it festive cheer, and a look forward into the new year to come. For those with an interest in intellectual property and the public domain it brings another treat, because every January 1st a fresh crop of works enter the public domain.

We’ll take a look at the wider crop around the day, but this year the big story is that Mickey Mouse, whose first outing was in 1928’s Steamboat Willie, is to get his turn to be released from copyright. [Jennifer Jenkins] from Duke University’s Center for the Study of the Public Domain, is using Mickey’s impending release to take a look at the law surrounding such a well-protected work.

Mickey has perhaps the greatest symbolism of all intellectual property when it comes to copyright terms, having been the reason for the Disney Corporation’s successive successful attempts to have copyright terms extended. Now even their reach is about to come to an end, but beware if you’re about to use him in your work, for the Mickey entering the public domain is an early outing, without gloves or the colours and eyes of his later incarnations. Added to that, Disney have a range of trademarks surrounding him. The piece makes for an interesting read as it navigates this maze, and makes some worthwhile points about copyright and the public domain.

Last year, we welcomed Fritz Lang’s Metropolis to the public domain. Meanwhile if you’re reading this in 2023, we believe our use of a header image featuring the 1928 Mickey to be covered by the doctrine of fair use.

Remembering Ed Roberts, The Home Computer Pioneer You Should Have Heard Of But Probably Haven’t

December 17, 2023 by 8 Comments

We’re pretty familiar with such names as Steve Wozniak, Bill Gates, Jack Tramiel, Nolan Bushnell, and the other movers and shakers of the 1970s home computer world. But there’s one person who towered among them for a few years before cashing out and leaving the computer business to pursue the life he’d always wanted. [Gareth Edwards] for Every has a fascinating profile of Ed Roberts, the man who arguably started the home computer boom but is now an obscure figure.

Even if you’ve never heard of Ed Roberts, you’ve likely heard of the product his company brought to market. The MITS Altair 8800 was the first computer to be sold as a home computer rather than for business or scientific use, and though its toggle switch interface now seems extremely quaint, its influence on every microcomputer that followed has been immense.

As followers of the retrocomputing scene, we know about the Altair, but perhaps more interesting is the story of MITS. Formed by a group of US Air Force veterans to produce rocket telemetry equipment, it pivoted to calculators, and as that market imploded in the early 1970s, the computer was a big gamble to save it from bankruptcy. It’s one that paid off, and as someone used to seeing technological cycles of boom and bust, Ed cashed out at the peak of the first wave. He followed his long-held ambition of becoming a doctor, and when, in 2010, he was near the end of his life, the hospital caring for him was shocked to find itself being visited by Bill Gates. It’s an article about a fascinating individual well worth reading.

The Altair, meanwhile, is a project that appears quite often here at Hackaday. Here’s a recreation of one as original as possible. The Mark 8 came out a little earlier but without complete kits or assembled units, so it didn’t get the traction — or the imitators — that the Altair did.

The Laptop Every British Kid Would Have Wanted For Christmas 1983

December 17, 2023 by 12 Comments

How can we convey to a world in which a 64-bit laptop can be a near-throwaway item, just how amazing a miniature laptop version of the 1980s Sinclair ZX Spectrum could have been? perhaps we don’t need to, because here in 2023 there’s a real one for all middle-aged geeks who had the original to drool over.

8-bit home computers were super-exciting for the kids of the day, but they were in no way portable and relied on a TV, frequently the family model in the living room. It’s safe to say that a portable version of one of those home computers, not in an Osborne-style luggable case but in a clamshell palmtop, would have been mind-blowing, so four decades later we’re fascinated by [Airrr17]’s portable Sinclair ZX Spectrum.

At its heart is a dev board using one of the STM32F4 series microcontrollers, and running the Spectrum as an emulator. Alongside that is an LCD, and perhaps what is physically the best part of this, a Spectrum keyboard complete with BASIC keyword decals, made with large-button tactile switches that have we think, printed paper on top. Add in a small lithium-polymer cell and associated electronics in a cute little palmtop case, and it’s about as good a portable Sinclair as we could have imagined. All the details can be found in a GitHub repository, and as if that weren’t enough there’s an assembly video we’ve placed below the break.

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Take The Minimal Pain Out Of ESP32 Programming

December 15, 2023 by 29 Comments

Perhaps without many of us realising it, our single board computers perform the task of making programming their processor or SoC a lot easier. They take care of setting the right lines or commands to put the chip in programming mode, they deal with timings, such that we simply fire our code from our dev environment without having to expend much thought. It’s not as though it’s difficult to program most microcontrollers, but there is usually a procedure to set the chip in programming mode. Tired of pressing buttons to achieve this with the ESP32, [DoganM95] took the time to create an all-in-one USB ESP32 programming board.

It’s a straightforward enough CH340C design that also has a USBC-PD chip on-board allowing powering of an attached ESP32 from PD sources. It’s all the stuff you’d find incorporated on a little dev board, without the ESP32, so while it’s nothing earth-shattering it’s also a neat and useful little addition to your arsenal. Unsurprisingly it’s not the first time someone’s created a similar board for a commercially available ESP32 module.

It’s A Microphone And A Spring Reverb All In One

December 15, 2023 by 8 Comments

We’re so used to reverb effects being simply another software plugin that it’s easy to forget the electromechanical roots of the effect. Decades ago, a reverb would have been a metal spring fed at one end with a speaker and attached at the other to a microphone. You may not see them often in the 2020s, which is probably why [Ham-made] has produced one. It’s not the type with a speaker providing the sound, though. Instead, this is a microphone in its own right with a built-in spring line.

Perhaps it’s not the best microphone possible, with a somewhat heavy diaphragm and 3D printed body. But the hand-wound spring transmits the sound down to a piezo disk which serves as the electrical element, and the whole thing screws together into quite the usable unit. There are a selection of sample MP3 files that provide an interesting set of effect-laden sounds, so if you fancy building one yourself, you can judge the results.

We think this may be the first reverb microphone we’ve seen, but we’re certainly no stranger to reverb projects. More common by far, though, are plate reverbs, in which the physical element in the system is a metal plate rather than a spring. We like it when the sound source is a Commodore 64.