Secret Knock Unlocks Door

May 25, 2020 by 12 Comments

Watch any movie about the years of prohibition, and you’ll probably see character gain admittance to a speakeasy by using a secret knock on the door. In the old movies, a little sliding door would open so the doorman could check you out and let you in. With [IsmailSan’s] electronic lock, the secret knock automatically unlocks the door. You can see a video of how it works, below.

(Ed Note: Grrr…GitHub repo got pulled between writing and publication. Go check out the in-links in the bottom paragraph if you’re interested in knock-detectors.)

The device uses a piezoelectric speaker to detect the knocking. A speaker is a transducer and like many transducers, it will work — to some extent — in either direction. A servo motor manages the deadbolt. An Arduino runs the whole thing.

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FPGA Raises Component Video From A Sinclair ZX Spectrum

May 25, 2020 by 39 Comments

An abiding memory of the early-80s heyday of 8-bit computing for many is operating their computer from the carpet in front of the family TV. While the kids in the computer adverts had parents who bought them a portable colour telly on which to play Jet Set Willy, the average kid had used up all the Christmas present money on the computer itself. The cable would have been an RF connection to the TV antenna socket, and the picture quality? At the time we thought it was amazing because we didn’t know any different, but with the benefit of nearly 40 years’ hindsight, it was awful.

For ZX Spectrum owners in 2020 a standard modification is to bring out a composite video signal, but [c0pperdragon] has gone a step or two beyond that with a component video interface. And this isn’t a mod in which the signals are lifted from the Spectrum’s colour encoder circuitry, instead it uses an FPGA hooked directly to the ULA chip to generate the component video itself.

The Altera chip sits on a little PCB designed to occupy the footprint of the original Astec modulator, and sports a neat bundle of wires hooked up to the various Spectrum signals it needs. There are a couple of jumpers to select the output type and resolution, it supports YPbPr or RGsB outputs and both 288p and 576p. If you think perhaps it looks a little familiar, that’s because it’s the sister project of an earlier board for the Commodore 64. So if you have a Spectrum and are annoyed by UHF and PAL, perhaps it’s worth a look.

2020 Hackaday Prize Hack Chat With Majenta Strongheart

May 25, 2020 by 3 Comments

Join us on Wednesday, May 27 at noon Pacific for the 2020 Hackaday Prize Hack Chat with Majenta Strongheart!

It hardly seems possible, but the Hackaday Prize, the world’s greatest hardware design contest, is once more at hand. But the world of 2020 is vastly different than it was last year, and the challenges we all suddenly face have become both more numerous and more acute as a result. We’ve seen hackers rise to the challenges presented by the events of the last few months in unexpected ways, coming up with imaginative solutions and pressing the limits of what’s possible. What this community can do when it is faced with a real challenge is inspiring.

Now it’s time to take that momentum and apply it to some of the other problems the world is facing. For the 2020 Hackaday Prize, we’re asking you to throw your creativity at challenges in conservation, disaster response, assistive technology, and renewable resources. We’ve teamed up with leading non-profits in those areas, each of which has specific challenges they need you to address.

With $200,000 in prize money at stake, we’re sure you’re going to want to step up to the challenge. To help get you started, Majenta Strongheart, Head of Design and Partnerships at Supplyframe, will drop by the Hack Chat with all the details on the 2020 Hackaday Prize. Come prepared to pick her brain on what needs doing and how best to tackle the problems that the Prize is trying to address. And find out about all the extras, like the “Dream Team” microgrants, the wild card prize, and the community picks.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, May 27 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Hacking The Road: Roundabouts

May 25, 2020 by 111 Comments

If you are from the US, you might be surprised at how prevalent roundabouts are in most of the world. Outside of Carmel, Indiana which has 125 roundabouts, these are pretty unusual in the United States though have been gaining in popularity over the past decade. It turns out, that while a modern roundabout is safer and more efficient than other intersection types, roundabouts got a bad rap early on and so the typical US driver still has a lot of anxiety when approaching one.

Prior to 1966, traffic circles were a spotty thing. In some cases, they were just big circular junctions. In others, the right-of-way rules were difficult to figure out or there were traffic lights and stop signs that did not lead to a better or safer driving experience.

Enter Frank Blackmore. In the UK, he introduced the “Priority Rule” which — simply — mandates that traffic entering a circle must give way to traffic already in the circle. Blackmore worked out that this method increases traffic flow by 10%. Although this kind of roundabout became law in the UK in 1966, the US was slow to adopt, primarily due to negative public opinion. In 2016, there were about 4,800 modern roundabouts in the U.S while France and the UK have roughly 55,000 combined.

So what are the virtues of the modern rounabout, and where did it come from? Let’s take a look.

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Lasercut Puzzlebox Is Safe-Cracking Fun

May 25, 2020 by 3 Comments

If you head out into the real world and start twiddling knobs on random safes, you might find yourself being hauled away by uniformed police. A safer pastime might be playing with your own puzzlebox at home, which is precisely what [thediylife] has done with this build.

The design implements a basic safe-cracking game, in which players try to guess the combination to the safe in a series of rounds. Input is via a rotary encoder, hooked up to the Arduino Uno inside. This project really wins because the finish looks so amazing. The safe is constructed out of 3mm MDF, which is lasercut to shape — an easy one to whip up in the average makerspace. The interface is fleshed out with a small OLED screen and some LEDs, while a servo acts as the lock which holds the door shut. When you see the underside of the face plate with components hot glued into holes you’ll really pale at how clean the business side ended up.

It’s a simple build, and one that would make a great party game with a prize hidden inside. We’ve seen other puzzle-box builds before, too — like the GPS-based reverse geocache build. Video after the break.

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A DIY Electronics Lab You Can Show Off With Pride

May 25, 2020 by 27 Comments

It’s hardly a secret that getting into a serious electronics habit can be detrimental to your bank account. A professional grade lab is simply unobtainable for many a tinkerer, and even mid-range hardware can set you back considerably. Which is why many folks just starting out will attempt to salvage or build as much of their equipment as possible. It might not always be pretty, but it’ll get the job done.

But this project by [Chrismettal] could end up completely reinventing the home electronic workspace. Using 3D printed frames, low-cost components, and a sprinkling of custom PCBs, this modular electronics workbench has all the bells and whistles an aspiring hardware hacker could need. As an added bonus, it looks like something that came off the International Space Station.

Inside the resistor substitution module.

This is one of those projects that simply can’t be done justice in a few paragraphs. If you’ve ever wanted to put together a dedicated electronics workbench but were put off by the cost of individual components, read though the fantastic documentation [Chrismettal] has prepared for the EleLab_v2. Is it all top-of-the-line hardware? No, of course not. But it’s more than suitable for the kind of work people in this community usually find themselves involved in on a weekend.

So what’s included? Naturally [Chrismettal] has created a power supply module, in both variable and fixed flavors. But there’s also a module for a resistor substitution, a component tester, and even a digital storage oscilloscope. You can mix and match the modules suit your needs, and if you want to create entirely new ones, the FreeCAD sources are available to get you started.

We’ve seen low-cost power supply modules before, and naturally we’re no strangers to cheap DSO kits. But this project wraps those devices and gadgets up into a form factor that anyone would be happy to have on their bench. We’re exceptionally interested in seeing new modules developed for the EleLab_v2, and doubt this is the last time you’ll see this impressive project grace these pages.

[Thanks to BrunoC for the tip.]

Ironclad Tips For Copper-Clad Prototyping

May 24, 2020 by 25 Comments

The idea of trying to prototype with SMD parts on the fly sounds like insanity, right? But then we watched [Leo Fernekes] walk calmly and carefully through his process (video, embedded below). Suddenly, SMD prototyping jumped onto our list of things to try soon.

[Leo] speaks from a lot of experience and tight client timelines, so this video is a fourteen-minute masterclass in using copper-clad board as a Manhattan-style scratch pad. He starts by making a renewable tool for scraping away copper by grinding down and shaping an old X-Acto blade into a kind of sharpened Swiss Army knife bottle opener shape. That alone is mind-blowing, but [Leo] keeps on going.

In these prototypes, he uses the through-hole version of whatever microcontroller is in the design. For everything else, he uses the exact SMT part that will end up on the PCB that someone else is busy designing in the meantime.

After laying the board out on paper, [Leo] carves out the islands of conductivity, beep-checks them for shorts, shines the whole thing with steel wool, and goes to town.

The tips and tricks keep coming as he makes jumps and joins ground planes with bare copper wire insulated with heat-proof Teflon tubing, and lays out the benefits of building up a stash of connectors and shelling out the money for a good crimp tool.

And why do you need a good crimp tool? Because when they’re done properly, crimped connections are stronger and more reliable than solder. There’s a lot more to them than you might think.

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