Arduino Orchestra Plays The Planets Suite

We’ve seen a great many Arduino synthesizer projects over the years. We love to see a single Arduino bleeping out some monophonic notes. From there, many hackers catch the bug and the sky is truly the limit. [Kevin] is one such hacker who now has an Arduino orchestra capable of playing all seven movements of Gustav Holst’s Planets Suite.

The performers are not human beings with expensive instruments, but simple microcontrollers running code hewn by [Kevin’s] own fingertips. The full orchestra consists of 11 Arduino Nanos, 6 Arduino Unos, 1 Arduino Pro Mini, 1 Adafruit Feather 32u4, and finally, a Raspberry Pi.

Different synths handle different parts of the performance. There are General MIDI synths on harp and bass, an FM synth handling wind and horn sections, and a bunch of relays and servos serving as the percussive section. The whole orchestra comes together to do a remarkable, yet lo-fi, rendition of the whole orchestral work.

While it’s unlikely to win any classical music awards, it’s a charming recreation of a classical piece and it’s all the more interesting coming from so many disparate parts working together. It’s an entirely different experience than simply listening to a MIDI track playing on a set of headphones.

We’d love to see some kind of hacker convention run a contest for the best hardware orchestra. It could become a kind of demoscene contest all its own. In the meantime, scope one of [Kevin’s] earlier projects on the way to this one – 12 Arduinos singing Star Wars tracks all together. Video after the break.

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How To Get Into Computer Game Development In 1982

If you are a follower of retrocomputing, perhaps you caught the interactive Black Mirror episode Bandersnatch when it came out on Netflix. Its portrayal of a young British bedroom coder finding his way into the home computer games industry of the early 1980s was of course fictional and dramatised, but for those interested in a real-life parallel without the protagonist succumbing to an obsession with supernatural book there’s a recent epic Twitter thread charting an industry veteran’s path into the business.

An acceptance letter like this from Artic Software would have been the wildest dream of any early-80s bedroom coder.
An acceptance letter like this from Artic Software would have been the wildest dream of any early-80s bedroom coder.

[Shahid Kamal Ahmad] now has an impressive portfolio spanning his his nearly four decades at the forefront of gaming, but his story starts in 1982 as a diabetic British Pakistani teenager from a not-privileged background in London writing in BASIC on his Atari 400. His BASIC games are good, but not good enough to gain acceptance from a publisher, so he sells his prized BMX bicycle to buy books on Atari 6502 assembler, a coffee percolator, and for curiosity’s sake, [Rodnay Zaks’] Programming the Z80. An obsessive three-month learning of 6502 programming and the Atari’s architecture ensues, and his game Storm in a Teacup sells to Artic Software.  He’s a professional game developer.

We follow him through a couple more projects until he arrives at Software Projects in Liverpool to try to sell his game Faces of Haarne, which he secures publishing for but also lands the opportunity of a lifetime. Jet Set Willy is the smash hit of the year on the ZX Spectrum, and they urgently need a Commodore 64 port. Can he do it in four weeks, with a bonus if he manages three? The subsequent descent into high-pressure assembly coding and learning the quirks between two completely different 8-bit architectures is an epic in itself, but he manages it in just a shade over the three weeks and they pay him the bonus anyway. His career in the computer game industry is cemented.

Through this tale the reminders of 1980s Britain are everywhere, far from bring a retro paradise it was a place hollowed out by industrial decline, with very little for those at the bottom of society to be optimistic about. His descriptions of casual racism are hard-hitting, but the group of computer-addicted friends at school is probably something that all teenagers of the era whose interests lay in that direction can relate to. The real hero of the story is probably his mother, who somehow found the resources for that Atari 400 and who provided him with much-needed support and encouragement.

This thread captures a unique and never-to-be repeated era in which a teenager could master an emerging technology and make a living in it without an expensive education. Like Bil Herd’s description of his career at Commodore in the same period, it’s well worth a read.

FPGA Retrocomputer: Return To Moncky

Part of the reason that retrocomputers are still so popular despite their obsolescence is that it’s possible to understand the entire inner workings of a computer like this, from the transistors all the way up to the software. Comparatively, it will likely be a long time (if ever) before anyone is building a modern computer from discrete components. To illustrate this point, plenty of 8-bit computers are available to either restore from original 80s hardware or to build from kits. And if you’d like to get even deeper into the weeds you can design your own computer including the instruction set completely from the ground up using an FPGA.

This project, called the Moncky project, is a step above the usual 8-bit computer builds as it is actually a 16-bit computer. It is built around an Arty Spartan-7 FPGA dev board running around 20 MHz and has access to 2 x 128 kB dual-port RAM for memory. To access the outside world there is a VGA output, PS/2 capability, SPI, and uses an SD card as a hard drive. This project really shines in the software, though, as the project creator [Kris Demuynck] builds everything from scratch in order to illustrate how everything works for educational purposes, and is currently working on implementing a C compiler to make programming the computer easier.

All of the project files, as well as all of the code, are available on the project’s GitHub page if you’d like to follow along or build on this homebrew 16-bit computer. It’s actually the third iteration of this computer, with the Moncky-1 and Moncky-2 being used to develop the more basic building blocks for this computer. While it’s not the first 16-bit computer we’ve seen implemented on an FPGA, it is one of the few that builds its own RISC instruction set and associated software rather than cloning a known existing processor. We’ve also seen some interesting x86 implementations on an FPGA as well.

Thanks to [koen-ieee] for the tip!

Elderly Remote Keeps Things Simple

If you are lucky, you’ve never experienced the heartbreak of watching a loved one lose their ability to do simple tasks. However, as hackers, we have the ability to customize solutions to make everyday tasks more accessible. That’s what [omerrv] did by creating a very specific function remote control. The idea is to provide an easy-to-use interface for the most common remote functions.

This is one of those projects where the technology puzzle is now pretty easy to solve: IR remotes are well-understood and there are plenty of libraries for recording and playing back signals. The real work is to understand the user’s challenges and come up with a workable compromise between something useful and something too complex for the user to deal with.

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Reinforced Concrete: Versatile At Any Size?

In our community we’re no strangers to making things, and there are plenty among us who devote their efforts to modelmaking. It’s uncommon, though, for a scale model of something to be made using the exact same techniques as whatever it’s copying. Instead a model might be made from card, foam, glassfibre, or resin. [tiny WORLD] takes an opposite tack, building scale model civil engineering projects just as they would have been for real. (Video, embedded below.)

Here, a scale model of the Hoover Dam bypass bridge is made as the original, from reinforced concrete. In place of rebar is a wire grid in place of wooden shuttering is what looks like foam board, the concrete is a much smoother mortar, but otherwise it’s the real thing. We see the various bridge parts being cast in situ, with the result being as strong as you’d expect from the original.

We can see that this is a great technique for modelling concrete buildings and structures, but it’s also a material that we think might have other applications at this scale. How would the rigidity, strength, and mass of small-scale reinforced cement compare to 20-20 extrusion, 3D-printed plastic, or wood, for example? Regardless, it’s interesting to watch, as you can see from the video below the break.

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A Raspberry Pi-based COVID Green Pass validator verifies a QR code on a phone.

COVID Green Pass Validator With Raspberry Pi

It seems like every nation is dealing with the plague a little differently. In June, the EU instated a COVID Green Pass which comes in the form of a paper or digital QR code. It was designed to grease the wheels of travel throughout Europe and allow access to nursing homes. As of early August, the Green Pass is now required of those 12 and older in Italy to gain access to bars and restaurants, museums, theaters, etc. — anywhere people gather in sizeable groups. The Green Pass shows that you’ve either been vaccinated, have had COVID and recovered, or you have tested negative, and there are different half-lives for each condition: nine months for vaccinated, six for recovered, and just forty-eight hours for a negative test.

[Luca Dentella] has built a Green Pass validator using a Raspberry Pi and a Raspi camera. Actual validation must be done through the official app, so this project is merely for educational purposes. Here’s how it works: the user data including their status and the date/time of pass issuance are encoded into a JSON file, then into CBOR, then it is digitally signed for authenticity. After that, the information is zipped up into a base-45 string, which gets represented as a QR code on your phone. Fortunately, [Luca] found the Minister of Health’s GitHub, which does the hard work of re-inflating the JSON object.

[Luca]’s Pi camera reads in the QR and does complete validation using two apps — a camera client written in Python that finds QRs and sends them to the validation server, written in Node.js. The validation server does formal verification including verifying the signature and the business rules (e.g. has it been more than 48 hours since Karen tested negative?) Fail any of these and the red LED lights up; pass them all and you get the green light. Demo video is after the break.

Are you Canadian? Then check this out, eh?

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The Simplest FT8 Transceiver You’ll Ever Build

Probably the most interesting facets of amateur radio in 2021 lie in the realm of digital modes. Using the limitless possibilities of software defined radios has freed digital radio communication from the limits of what could be done with analogue electronics alone, and as a result this is a rare field in which radio amateurs can still be ahead of the technological curve. On of these newer digital modes is FT8 created by the prolific [Joe Taylor K1JT].

And it’s for this  mode that [Charles Hill] has created an easy-to-build transceiver. Its brains are aTeensy 3.6, while the receive side is a Si4735 receiver chip and the transmitter is a Si5351 programmable clock chip driving a Mini-Circuits GVA84 power amplifier with an appropriate filter. The interface is via a touchscreen display. It relies on existing work that applies a patch on-the-fly to the Si4735 receiver chip for SSB reception, and another project for the FT8 software.

The charm of this transceiver is that it can be assembled almost in its entirety from modules. Some radio amateurs might complain that homebrew radios should only use the most basic of components assembled from first principles, but the obvious answer to that should be that anything which makes radio construction easier is to be welcomed. If the 100 mW output power seems a bit low it’s worth remembering that FT8 is a weak signal mode, and given the right propagation conditions the world should be able to hear it despite the meagre output.

We’ve featured quite a few radios using the Si47XX series, which can be made into very tidy receivers indeed.