Bare Metal Gives This Pi Some Classic Synths

April 19, 2022 by Jenny List 18 Comments

We’re used to seeing the Raspberry Pi crop up in a wide range of the projects we show you here, but it’s fair to say that they usually feature some sort of operating system. There’s another way to use a Pi, more akin to using a microcontroller such as the Arduino: by programming it directly, so-called bare-metal programming. MiniDexed is an example, and it copies a classic Yamaha professional synthesiser of the 1980s, by emulating the equivalent of eight of the company’s famous DX7 synthesisers in one unit. It takes almost any Pi, and with the addition of an audio board, a rotary encoder, and an LCD display, makes a ready-to-go unit. Below the break is a video of it in operation.

It’s fair to say that we’re not experts in Raspberry Pi bare metal programming, but it’s worth a diversion into the world of 1980s synthesisers to explore the DX7. This instrument was a staple of popular music throughout the 1980s and was a major commercial success for Yamaha as an affordable FM synthesiser. This was a process patented at Stanford University in the 1970s and subsequently licensed by the company, unlike other synths of the day it generated sound entirely digitally. It’s difficult to overestimate the influence of the DX7 as its sound can be heard everywhere, and it’s not impossible that you own a Yamaha FM synth even today if you have in your possession a sound card.

Curious about the DX7? Master chip-reverse-engineer [Ken Shirriff] exposed its secrets late last year.

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Ray-Traced Doom Really Shines!

April 18, 2022 by Jonathan Bennett 13 Comments

We’re huge fans of taking retro games and adding new graphics features to them, so you had to know that when [Sultim Tsyrendashiev] released his ray-traced Doom engine, we would have to cover it. Now this does break with tradition — instead of running Doom on every conceivable platform, this version requires an AMD or Nvidia ray tracing capable card. On the other hand, the spirit of Doom is certainly alive, as ray-traced Doom has already been demonstrated on the Steam Deck. Check out the video below for a demo, and come back after the break for more info.

The most exciting part of this graphical feat may be the RayTracedGL1 library that “simplifies the process of porting applications with fixed-function pipeline to real-time path tracing.” Besides Doom, there’s also been demos made of Serious Sam and Half-Life 1. There’s even experimental Linux support! We managed to compile and test it on our system, running a 6700 XT and Fedora 35 with bleeding edge Mesa. There are a few visual glitches to work out, but it’s an outstanding project so far. The only complaint we have is that it’s based on prboom, not the still-maintained GZDoom, though with enough attention who knows where the project will go. If this leaves you hungry for more, check out more retro-upgrades, or Doom on more devices.

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Honey, Did You Feed The Lamp? Company Wants To Create Living Light Bulbs

April 18, 2022 by Al Williams 30 Comments

The BBC’s [Peter Yeung] had an interesting post about a small French town experimenting with using bioluminescent organisms to provide lighting. A firm called Glowee is spearheading the effort in Rambouillet and other towns throughout France, using a variety of biological techniques to harness nature’s light sources.

Glowing animals are reasonably common ranging from fireflies to railroad worms. In the case of the French street lighting, Glowee is using a marine bacterium known as aliivibrio fischeri. A salt-water tube contains nutrients and when air is flowing through the tube, the bacteria glow with a cool turquoise light. The bacteria enter an anaerobic state and stop glowing if you shut off the air.

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2022 Sci-Fi Contest: Schrödinger’s Trigger Is Trained On Electrons, Not Cats

April 18, 2022 by Kristina Panos 20 Comments

While it’s true that Hackaday scribes and their families are sadly unable to compete in our contests, Hackaday alum are more than welcome to throw their hat in the ring. [Legionlabs] even made a game of it — they used only parts from the scrap heap, and even played beat the clock to build a real, science-fictiony, working thing in eight hours or less.

Okay, cool, but what does it do? Well, put simply, a rising edge on the input drives one of two outputs, lighting one of two drool-worthy flanged LEDs. Which output will [alight] is unknowable until observed, thus the Schrodinger’s aspect. In practice, the output is determined by sampling. In this case, the sampling is of the time difference between three electron-tunneling events.

Stage one of Schrodinger’s Trigger is a pair of inputs — one variable 10-15 VDC input and 5 VDC input. Then comes the electron-tunneling event generator. [Legionlabs] is reverse-biasing a semiconductor junction (a 2N551 transistor). What does that mean? If we consider the junction as a diode and apply voltage in the wrong direction, what happens? At best, nothing; at worst, the smoke monster appears to admonish us.

But with a semiconductor acting as a diode, some electrons are bound to jump across the junction. This is known as tunneling, and is a useful phenomenon as it is purely random.

Stage three consists of amplifying the signal from these rebel electrons via hex inverters. Why not op-amps? The CD4069s were cheaper and within reach. Finally, the amplified signals are sampled with an ATtiny12, and some assembly logic figures out which LED to light.

It’s nice to see an entry that leans more toward the science side of things while winning aesthetically. We dig the nice ABS enclosure, and are totally envious of [Legionlabs]’ access to flanged LEDs and those glass table top mounting point discs in the corners.

The Epic Journey Of Repairing An HP 9830A Desktop Computer From The 1970s

April 18, 2022 by Robin Kearey 10 Comments

We love our retrocomputers here at Hackaday, and we’re always delighted to see someone rescue an historic artefact from the landfill. Sometimes, all it takes is replacing a broken power switch or leaky capacitor; other times you need to bring out the oscilloscope and dig deeper into internal circuitry. But the huge amount of work [Jerry Walker] put into bringing an HP 9830A back on its feet is something you don’t see very often.

If you’re not familiar with the HP 9830A, it’s a desktop computer from the early 1970s, fully built from discrete logic gates. The machine on [Jerry]’s desk turned out to be completely dead, with not even the fan spinning up. This was caused by a dodgy power switch, but replacing that switch was just the beginning: there were several bad components inside the power supply as well as a huge amount of moist dirt on the back of the motherboard. After a thorough cleaning and the replacement of several failed components, all four power rails were running within spec again.

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PicoCat, printed in yellow filament, looking at you with its ultrasonic sensor eyes

Build Your Own Cat – Some Assembly Required

April 18, 2022 by Arya Voronova 4 Comments

Robotic pets are sci-fi material, and [Kevin McAleer] from [Kev’s Robots] is moving us all ever so closer towards a brighter, happier, more robotic future. One of his latest robot builds, PicoCat, is a robot cat with servo-driven paws. It follows in the footsteps of the OpenCat project made by Dr. Rongzhong Li back in 2016, and we’re always happy seeing someone pick up where another hacker left off. [Kevin] took heavy inspiration from the OpenCat design – rebuilding it with hardware more friendly and accessible for makers today.

Projects like these, involving data processing and calculations to get the servos moving just right, stand to benefit from the computing power of recently released RP2040 MCU. As such, the Pimoroni Servo 2040 board is a crucial component of this build, being both the brains of the project and also a PIO-boosted driver for the eleven servos helping this robot come alive. This cat’s eyes are an ultrasonic sensor, and you can add a whole lot more sensors for any robotic intention of yours. Don’t expect this kitty to jump one meter high or scratch your favourite couch to death just yet, but there’s already a lot of potential, especially coupled with a small speaker.

Does this robotic cat interest you, whether it’d be due to your sci-fi propensity or a cat hair allergy? You’re in luck, because [Kevin] is keeping things firmly in the “open-source everything” realm. MicroPython code is stored in a GitHub repo, STLs are in a .zip linked on the page, and there’s plenty of renders to never leave you confused on what goes where. With all these resources, you can source the servos and the boards, fire up your 3D printer and sit down to assemble your own PicoCat. But not just that, [Kevin] also recorded three whole streams with insights, giving us over four hours of how-it-came-to-be video material for us to learn from. First, two streams of him designing the PicoCat in Fusion360, and then, him talking about the way he creates unit tests in MicroPython to improve his robots’ reliability and significantly reduce the amount of bugs cropping up.

This is not the last we will hear from [Kevin]’s robot-filled workshop, and previously, we’ve covered his Cray-1-shaped Pi Zero cluster system and a Raspberry Pi theremin, both as open and reproducible as this kitty! As you assemble yourself a PicoCat, or perhaps a Stanford Pupper or any of the other lovely quadru-pets we’ve previously featured, you might wonder how to properly move the servos, and we’ve covered a project that teaches you specifically that.

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Ask Hackaday: Would A Scooter Get You Back To The Office?

April 18, 2022 by Kristina Panos 73 Comments

So we’re two plus years into the pandemic at this point. Are you still working from home in the most comfortable clothes ever sewn? We figure that of the lot of you who said goodbye to that drab, tiled carpet in 2020, most have probably heard rumblings about returning to the office. And probably a good portion have at least been forced into a hybrid schedule.

Lots of companies would love to see their employees once again milling about all those ~~glass and steel observation tanks~~ office buildings they pay so much for. And while some are likely just forcing employees to come back, others are offering incentives, such as Google. The tech giant recently partnered with electric scooter manufacturer Unagi to provide a “Ride Scoot” program designed to lure many of Google’s US-based employees back to those brightly-colored code playgrounds they call offices with a fun mode of private transportation. The plan is to offer a full reimbursement of the monthly subscription fee for Unagi’s Model One folding scooter, which retails for $990.

The subscription is normally $49 a month plus a one-time $50 sign-up fee, but this amount will be slightly discounted (and waived) for eligible Google employees. There is one caveat to the system: an employee must use the scooter for a minimum of nine commutes to the office per month, although Google says they’re gonna be a bro about it and use the honor system.

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