When An Engineering Education Doesn’t Teach You How To Really Make Anything

In the sweltering temperatures of an unusually hot European heatwave, I found myself having a chat with  a friend of mine from my university days. After discussing the health of his cat who had solved the problem of a fur coat on a hot day by flattening himself out on the concrete floor in the coolest place in the house, we moved on to tech matters. We’ve known each other for not far short of four decades, so this is familiar territory for us. The problems that come with taking a prototype to manufacturing, a process which even the most seasoned of engineers can slip up on.

The Difference Between Making, And Making For Manufacture

If you’ve ever taken a project and replicated it, you will know the progression. If you’re making five or ten widgets, you can debug and rework as needed, tweak things, and get things going. If you’re making more then this, the process consumes a greater proportion of your time, until a point at which manufacture becomes impractical. Maybe that’s around fifty boards, sometimes more or less. Continue reading “When An Engineering Education Doesn’t Teach You How To Really Make Anything”

Why The NES Put Out A Wobbly Picture

The NTSC television standard is a masterpiece of mid-century engineering, to pack a color image into the transmission bandwidth of a monochrome one, and to do so while maintaining backward compatibility with earlier monochrome TV sets. In terms of its timings and choice of sync and carrier frequencies it’s elegantly thought out for maximum quality on a 1950s round-CRT color TV set.

The trouble is, that while the standards are exacting, the receivers are quite forgiving, and will display adequately even with substantially off-spec video. [Nicole Express] is here with an in-depth examination of a time when that was pushed just a little bit too far, explaining why the Nintendo Entertainment System (NES) displayed wobbly color images.

We’re treated to a run-through of the NTSC standard itself, and a look at how some of the other consoles and home computers of that era either had similar problems, or managed to avoid them. The key lies in the exacting timing required to achieve perfect interlacing, and the NES’s use of a single crystal to provide all the clocks. The dot clock on adjacent frames was almost right, but not quite, leading to a side-to-side wobble that while barely perceptible, was exacerbated by some graphics. It’s a fascinating read.

We’ve looked at composite video in detail in the past.


NES image: JCD1981NL, CC BY 3.0.

The Coolest Hat At The Hacker Camp

People in hotter parts of the world may permit themselves a grin at this, but Europeans have recently been suffering under an unseasonal June heatwave. Most of us have been cowering inside with our air conditioners, but not [Making Stuff With Mike]. He’s adapting a safety helmet with a Noctua fan for only slightly uncool on-the-go cooling.

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Old Midi Instruments Don’t Like Modern Midi. What’s To Be Done?

In theory, MIDI is an electrical and protocol standard that allows any such equipped instrument or computer to talk to any other. But as the wonderfully named [Knob Monster] will tell you, when the computer is new, and the instrument is old, it ain’t that simple.

They specialise in using the Web MIDI interface to allow browser control of an instrument. This might typically be done with a USB to MIDI interface, but in this lies a problem. The 8-bit microprocessor on a 1983 synth has problems keeping up with the rapid-fire data that spews relentlessly from the supercomputer-grade machine controlling it, and bad things happen as a result.

Expensive MIDI interfaces have a buffer built in, but a better solution lies in the Web MIDI code itself. They detail how to use the Web MIDI API’s built-in packet scheduler to slow things down a little and let your Yamaha DX7 chill a bit.

Meanwhile, if you need a USB to MIDI interface, we’ve covered one in the past.

The Persistent Display We Never Got

We all know the e-ink persistent displays, as they’re cheap and plentiful enough to have become ubiquitous in applications such as supermarket price labels. But we don’t often see some of the other technologies that almost did the same thing. The BBC Archive has a report from 1986 showing one of them, a prototype display from STC.

E-ink relies on flipping the arrangement of black and white particles in its pixels, while this one has a fluid in which the molecules are aligned to let light through, or dispersed randomly, at which point they block light. Frustratingly, we aren’t told what the liquid is, but we are given what might be the reason that we’ve never seen one. The activation voltage is rather high at 200 volts. It’s still a fascinating glimpse of something we might have had, with some tasty early-PC-era portables along the way.

The BBC archive has served up quite a bit of retro goodness over time, and we’ve certainly featured one or two of them over time. A recent one was this demonstration of email via a flight to Amsterdam, from the same year as today’s display.

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Time Never Moves Slowly With This Clock

A clock is by its very nature a device for measuring time, and thus it moves forward at a constant rate. But how about in a theatrical setting, where time runs at the whim of the director? For the stage, a clock with more flexibility is required. To this endeavor [Playful Technology] has you covered, with a larger than life stage clock whose hands are independently controllable by DMX.

Behind the clock is a very unusual part, not the modified clock mechanism one might expect, but a dual stepper motor with a concentric shaft. This is driven by an Arduino with a stepper driver shield more familiar from the world of 3D printers, and an RS485 interface for DMX interfacing. The hands are built in OpenSCAD, and 3D printed to be an interference fit on the shafts. The DMX controller software has a handy rotating knob style interface, allowing easy hand manipulation.

You can see the results in the video below, complete with an exhaustive dissection of the Arduino code. Meanwhile DMX is itself a fascinating subject, and in the past we’ve taken a deep dive into RS485.

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The Organ That Forgot To Use Transistors

When we think of 1960s synthesizers it’s usual to imagine instruments with vast arrays of controls and patch cables for configuring their many filters, oscillators, and other parameters. They created the templates for much of what we know today as electronic music.

In all the rush to look at full-blown synths though, it’s easy to forget their more mundane cousin, the electric organ. These instruments graced many a ’60s suburban home or church hall, and [Emma Repairs] has an interesting one. It’s a Philips Philicordia, and it’s sent us here at Hackaday down one of those rabbit holes when we should really be writing.

The instrument is a relatively straightforward single voice electric organ on the outside, but under the hood it’s a different matter. In an age when the transistor was revolutionizing electronic music, the folks in Eindhoven designed this one using tubes. There are a set of conventional enough tubes performing the role of amplifiers and oscillators, but the real party piece of this unit is the array of neon tube dividers. A neon bulb can be used as a switching element, and in those days when affordable digital logic chips were several years away, it made sense to use them in digital circuits.

The inside of the Philicordia is a feast of vintage Philips parts that will be instantly familiar to anyone who’s worked on Western European electronics of this era. The exterior design of the instrument screams understated early-1960s cool, and after she’s introduced it you can hear her playing it in the video below. Further down that rabbit hole we found that one of these instruments provided the distinctive organ sound on Chris Montez’s 1962 hit Let’s Dance, so they weren’t all uncool.

Continue reading “The Organ That Forgot To Use Transistors”