Retrotechtacular: Nellie The School Computer

When did computers arrive in schools? That should be an easy question to answer, probably in the years around 1980. Maybe your school had the Commodore Pet, the Apple II, or if you are British, the Acorn BBC Micro in that period, all 8-bit microcomputers running a BASIC interpreter. That’s certainly the case for the majority of schools, but not all of them. In early 1969 the BBC’s Tomorrow’s World visited a school with a computer, and in both technology and culture it was a world away from those schools a decade later that would have received those BBC Micros.

The school in question was The Forrest Grammar School, Winnersh, about 35 miles west of London, and the computer in question was a by-then-obsolete National Elliott 405 mainframe that had been donated four years earlier by the British arm of the food giant Nestlé. The school referred to it as “Nellie” — a concatenation of the two brand names. It seems to have been the preserve of the older pupils, but the film below still shows the concepts of its operation being taught at all levels. We get a brief look at some of their software too — no operating systems here, everything’s machine code on paper tape — as a teacher plays a reaction timer game and the computer wins at noughts and crosses (tic-tac-toe). One of them has even written a high-level language interpreter on which younger children solve maths problems. Of course, a 1950s mainframe with hundreds or thousands of tubes was never a particularly reliable machine, and we see them enacting their failure routine, before finally replacing a faulty delay line.

This is a fascinating watch on so many levels, not least because of its squeaky-clean portrayal of adolescent boys. This is what teenagers were supposed to be like, but by the late 1960s they must in reality have been anything but that away from the cameras. It’s a contrast with fifteen or twenty years later, the computer is seen as an extremely important learning opportunity in sharp opposition to how 8-bit computers in the 1980s came to be seen as a corrupting influence that would rot young minds.

Of course, these youngsters are not entirely representative of British youth in 1969, because as a grammar school the Forrest was part of the top tier of the selective education system prevalent at the time. There would certainly have been no computers of any sort in the local Secondary Modern school, and probably the BBC’s portrayal of the pupils would have been completely different had there been. In 1974 the Government abolished the grammar school system to create new one-size-fits-all comprehensive schools, one of which the Forrest school duly became. Following the vagaries of educational policy it is now an Academy, and there is probably not a room within it that does not contain a computer.

So what of Nellie? Because of the film there are plenty of online references to it in 1969, but we could only find one relating to its fate. It was finally broken up in 1971, with the only surviving component being a delay line. More than one Elliott machine survives in museum collections though, and your best chance in the UK of seeing one is probably at the National Museum Of Computing, in Bletchley.

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Hackaday Podcast 011: Weird Keyboards, Salvaging LCD Screens, And Mike Interviews Ivan Of Espressif In Shanghai

With our intrepid Editor in Chief Mike Szczys off being kind of a big deal in China, Managing Editor Elliot Williams is joined by Staff Writer Tom Nardi to talk about all the hacks that were fit to print over the past week. Join us as we talk about the wide world of custom mechanical keyboards, reviving a woefully antiquated display technology, building your own RC transmitter out of stuff you have laying around the lab, and the unexpected parallels between Pepto Bismol and rocket fuel. We’ll also look at what it takes to build a robust embedded system, and see if we can’t figure out a way to draw schematics worth looking at. Plus, hang around until the end of the episode to hear Mike interview the man instrumental in getting the ESP8266 to play nice with Arduino, and now running firmware for the ESP32.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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Robot Telephone Operator Handles Social Media For You

Social media has become pervasive in modern life. It can be impossible to get so much as an invite to a party without offering up your personal data at the altar of the various tech companies. [David] wanted to avoid the pressures of seeing countless photos of people climbing mountains and eating tacos, but also didn’t want to ostracize himself by avoiding social media altogether. Naturally, automation was the answer.

[David] aptly named his robot Telephone Operator, and that’s precisely what it does. Stepper motors and a servo allow the robot’s capacitive appendage to interact with the touch screen on [David]’s iPhone. A camera is fitted, and combined with OpenCV, the robot is capable of a great many important tasks.

Liking Instagram posts? Done. Reposting inane tweets? Easy. Asking your pal Mike what’s up? Yep, Telephone Operator has it covered. Given the low quality of human interaction on such platforms, it’s entirely possible [David] has the Turing Test beat without even trying. The robot even has that lazy continuous Sunday morning scroll down pat. It’s spooky stuff.

Of course, if you’re too in love with social media to trust an automaton, you might instead prefer to wear your likes on your sleeve. Video after the break.

[Thanks to dechemist for the tip!]

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Faster Computers Lead To Slower Experiences?

Ever get that funny feeling that things aren’t quite what they used to be? Not in the way that a new washing machine has more plastic parts than one 40 years its senior. More like “my laptop can churn through hundreds of gigaflops, but when I scroll it doesn’t feel great.” That perception of smoothness might be based on a couple factors, including system latency. A couple years ago [danluu] had that feeling too and measured the latency of “devices I’ve run into in the past few months” (based on this list, he lives a more interesting life than we do). It turns out his hunch was objectively correct. What he wrote was a wonderful deep dive into how and why a wide variety of devices work and the hardware and software contributors to latency.

Let’s be clear about what “latency” means in this context. [danluu] was checking the time between a user input and some response on screen. For desktop systems he measured a keystroke, for mobile devices scrolling a browser. If you’re here on Hackaday (or maybe at a Vintage Computer Festival) the cause of the apparent contradiction at the top of the charts might be obvious.

Q: Why are some older systems faster than devices built decades later? A: The older systems just didn’t do much! Instead of complex multi-tasking operating systems doing hundreds of things at once, the CPU’s entire attention was bent on whatever user process was running. There are obvious practical drawbacks here but it certainly reduces context switching!

In some sense this complexity that [danluu] describes is at the core of how we solve problems with programming. Writing code is all about abstraction. While it’s true that any program could be written directly in machine code and customized to an individual machine’s hardware configuration, it would be pretty inconvenient for both developer and user. So over time layers of sugar have been added on top to hide raw hardware behind nicer interfaces written in higher-level programming languages.

And instead of writing every program to target exact hardware configurations there is a kernel to handle the lowest layers, then layers adding hotplug systems, power management, pluggable module and driver infrastructure, and more. When considering solutions to a programming problem the approach is always recursive: you can solve the problem, or add a layer of abstraction and reframe it. Enough layers of the latter makes the former trivial. But it’s abstractions all the way down.

[danluu]’s observation is that we’re just now starting to curve back around and hit low latency again, but this time by brute force! Modern solutions to latency largely look like increasingly exotic display technologies and complex optimizations which reach from UI draw functions all the way down to the silicon, not removing software and system infrastructure. It turns out the benefits of software complexity in terms of user experience and ease of development are worth it most of the time.

For a very tangible illustration of latency as applied to touchscreen devices, check out the Microsoft Research video after the break (linked to in [danluu]’s piece).

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The Multichannel Field Recorder You Can Build Right Now

Field recorders, or backpackable audio recorders with a few XLR jacks and an SD card slot, are a niche device, and no matter what commercial field recorder you choose you’ll always compromise on what features you want versus what features you’ll get. [Ben Biles] didn’t feel like compromising so he built his own multichannel audio DSP field recorder. It has a four channel balanced master outputs, with two stereo headphone outputs, eight or more inputs, digital I/O, and enough routing for multitrack recording.

Mechanically, the design of the system is a 3D printed box studded on every side with various connectors and patch points. This is what you get when you want a lot of I/O, and yep, those are panel mount connectors so get ready to pony up on the price of your connectors. The analog front end is a backplane sort of thing on a piece of perfboard, containing an eight channel differential I/O.

Of course any audio recorder is awful to use unless there’s a great user interface, and for that you can’t get any better than a high-resolution touchscreen on a phone. This led [Ben] to use Bluetooth to connect to an app showing the gain, levels, a toggle for phantom power, and a checkbox for line or microphone. If that’s not enough there are also some MIDI knobs for volume, because MIDI is still great for user input. It’s everything you want in a portable recording rig, and yes, there is a soundcloud demo. You can also check out a demo video below.

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A Steady Hand Makes This Chip Work Again

What do you do when you’re working with some vintage ICs and one of the tiny legs pops off? That’s what happened to [Kotomi] when working with an old Super Nintendo. A single lead for the sound chip just snapped off, leaving [Kotomi] one pin short of a working system (the Google Translatrix). This is something that can be fixed, provided you have a steady hand and a rotary tool that’s spinning at thousands of RPM.

Fixing this problem relies on a little bit of knowledge of how integrated circuits are built. There’s a small square of silicon in there, but this tiny die is bonded to a metal leadframe, which looks like the ribcage of a robotic centipede. This leadframe is covered in epoxy, the pins are bent down, and you have an IC. Removing just a tiny bit of epoxy grants access to the leadframe which you can then solder to. Don’t breathe the repair, it’s not pretty, but it does work.

While this technique makes use of a Dremel to break into the chewy nougat center of a vintage chip, and in some ways this could be called decapsulation, it really isn’t. We’ve seen people drop acid to get to the center of a chip and a really hot torch will get to the middle of a ceramic chip, but this technique is just accessing the lead frame of the IC. All ICs have a stamped (or photoetched) metal frame to which the silicone die is bonded. Running a Dremel against some epoxy doesn’t access the silicon, but it does grant access to the signals coming off the chip.

Make Your Own Quantum Dots

Quantum dots certainly sound as if they should be something cool, but carry the hazardous baggage of being sometimes made from cadmium which can be dangerous. What are they? In essence, they are nanometer-scale particles, so small that when high energy light hits them, the photons will be absorbed and re-emitted at a lower energy state. You can easily make non-toxic quantum dots in your kitchen. Apart from the cool factor, they can be used as fluorescent dyes, inks, and possibly paints. [StrangelyAmusing] explains how in the video below.

You don’t need much in the way of equipment. A microwave oven, a Pyrex (borosilicate) container, and gloves. You’ll also need plastic pipettes and a blacklight — possibly the most exotic two items on the list. The ingredients are equally mundane: vinegar, baking soda, water, and sugar.

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