Misc Hacks

4173 Articles

Nixie Power Supply Shows Ins And Out Of Offshore Manufacturing

April 3, 2019 by 9 Comments

[Tony] built a high-efficiency power supply for Nixie tube projects. But that’s not what this post is about, really.

As you read through [Tony]’s extremely detailed post on Hackaday.io, you’ll be reading through an object lesson in electronic design that covers the entire process, from the initial concept – a really nice, reliable 170 V power supply for Nixie tubes – right through to getting the board manufactured and setting up a Tindie store to sell them.

[Tony] saw the need for a solid, well-made high-voltage supply, so it delved into data sheets and found a design that would work – as he points out, no need to reinvent the wheel. He built and tested a prototype, made a few tweaks, then took PCBWay up on their offer to stuff 10 boards for a mere $88. There were some gotchas to work around, but he got enough units to test before deciding to ramp up to production.

Things got interesting there; ordering full reels of parts like flyback transformers turned out to be really important and not that easy, and the ongoing trade war between China and the US resulted in unexpected cost increases. But FedEx snafus notwithstanding, the process of getting a 200-unit production run built and shipped seemed remarkably easy. [Tony] even details his pricing and marketing strategy for the boards, which are available on Tindie and eBay.

We learned a ton from this project, not least being how hard it is for the little guy to make a buck in this space. And still, [Tony]’s excellent documentation makes the process seem approachable enough to be attractive, if only we had a decent idea for a widget.

Mains Power Supply For ATtiny Project Is Probably A Bad Idea

April 2, 2019 by 45 Comments

When designing a mains power supply for a small load DC circuit, there are plenty of considerations. Small size, efficiency, and cost of materials all spring to mind. Potential lethality seems like it would be a bad thing to design in, but that didn’t stop [Great Scott!] from exploring capacitive drop power supplies. You know, for science.

The backstory here is that [Great Scott!] is working on a super-secret ATtiny project that needs to be powered off mains. Switching power supplies are practically de rigueur for such applications, but compared to the intended microcontroller circuit they are actually quite large, and they’ve just been so done before. So in order to learn a thing or two, [Scott!] designed a capacitive dropper supply, where the reactance of the cap acts like a dropping resistor to limit the current. His first try was just a capacitor in series with an LED; this didn’t end well for the LED.

To understand why, he reverse-engineered a few low-current mains devices and found that practical capacitive droppers need a few more components, chiefly a series resistance to prevent inrush current from getting out of hand, but also a bridge rectifier and a zener to clamp things down. Wiring up all that resulted in a working capacitive dropper supply, but a the cost of as much real estate as a small switcher, and with the extra bonus of being potentially lethal if the power supply is plugged in the wrong way. Side note: we thought German line cords were polarized to prevent this, but apparently not? (Ed Note: Nope!)

As always, even when [Great Scott!]’s projects don’t exactly work out, like a suboptimal 3D-printed BLDC or why not to bother building your own DC-AC inverter, we enjoy the learning that results.

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Sensor-Laden Pigeons Gather Data For Urban Weather Modeling

March 26, 2019 by 30 Comments

When it comes to gathering environmental data in real-world settings, urban environments have to be the most challenging. Every city has nooks and crannies that create their own microenvironments, and placing enough sensors to get a decent picture of what’s going on in all of them is a tough job. But if these sensor-laden pigeons have anything to say about it, the job might get a bit easier.

The idea for using pigeons as biotelemetry platforms comes to us from the School of Geography, Earth, and Environmental Sciences at the University of Birmingham in the UK. [Rick Thomas], lead investigator on the “CityFlocks” project, explains that meteorological models are hampered by a lack of data about the air in the urban canyons formed by tall buildings. Placing a lot of fixed sensors has a prohibitive cost, and using drones to do the job would probably cause regulatory problems, especially given recent events. But pigeons are perfect for the job once they’re outfitted with an “Avian-Meteorology Instrumentation Package (AvMIP)”. From the photographs we’re guessing the AvMIP is a pretty simple data logger with GPS and inputs for the usual sensors, all powered by a small LiPo pack. Luckily, the pigeons used are all domesticated racing birds that return to the nest, so no radio transmitter is needed, but if other urban avians such as peregrine falcons and seagulls are used then a future AvMIPS might leverage pervasive WiFi networks to upload data.

It’s not the first time we’ve seen mobile platforms used to fill in gaps in weather data, of course. And if this at all puts you in mind of that time pigeons were used to guide bombs, relax – no pigeons were harmed in the making of this research project.

Thanks to [Itay Ramot] for the tip [via Gizmodo].

Magnetic Bearings Might Keep This Motor Spinning For Millennia

March 25, 2019 by 43 Comments

We see our share of pitches for perpetual motion machines in the Hackaday tips line, and we generally ignore them and move along. And while this magnetic levitation motor does not break the laws of thermodynamics, it can be considered a perpetual motion machine, at least for certain values of perpetuity.

The motor that [lasersaber] presents in the video below is unconventional, to say the least. It’s not a motor that can do any useful work, spinning at a stately pace beneath its bell-jar enclosure as it does. The design is an extension of [lasersaber]’s “EZ-Spin” motor, which we’ve featured before, and has the same basic layout – a ring of coils wired in series forms the stator, while a disc bearing permanent magnets forms the rotor. The coils, scavenged from those dancing flowerpot solar ornaments, are briefly energized by the rotor passing over a reed switch, giving the rotor a little boost.

The difference here is that rather than low-friction sapphire bearings, this motor uses zero-friction magnetic levitation using pyrolyzed graphite discs. The diamagnetic material hovers above a rare-earth ring magnet, supporting a slender vertical shaft that holds the rotor and another magnetic bearing at the top. It’s fussy to adjust, but once it’s stable, the only friction in the system should be the drag caused by air in the bell jar. [lasersaber]’s current measurements of the motor running at slow speed are hard to believe – 150 nanoamps – leading to an equally jaw-dropping calculated run-time on a single AA battery of 89 millennia.

[lasersaber] is the first to admit that he’s not confident with his measurements, but it seems clear that his motor will likely outlive any chemical battery used to power it. Whatever the numbers are, we like the styling of the thing, and the magnetic bearings are cool too.

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Imitating Art In Life With A Reverse-Engineered Tattoo

March 23, 2019 by 6 Comments

In general, tattoo artists are not electrical engineers. That’s fine; the world needs both professions. But when you need a circuit designed, you’re better off turning to an EE rather than a tattoo artist. And you certainly don’t want an EE doing your new ink. Disaster lies that way.

Surprisingly, [Missa]’s tattoo of a heart-shaped circuit turned out at least to be plausible design, even if it’s not clear what it’s supposed to do. So her friend [Jeremy Elson] took up the challenge to create a circuit that looked like the tattoo while actually doing something useful. He had to work around the results of tattoo artistic license, like sending traces off to the board’s edge and stranding surface-mount components without any traces. The artist had rendered an 8-pin DIP device, albeit somewhat proportionally challenged, so [Jeremy] went with an ATtiny85, threw on a couple of SMD resistors and a cap, and placed two LEDs for the necessary blinkenlights. Most of the SMDs are fed from traces on the back of the board that resurface through vias, and a small coin cell hidden on the back powers it. One LED blinks “Happy Birthday [Missa]” in Morse, while the other blinks prime numbers from 2 to 23 – we’ll assume this means it was [Missa]’s 23rd birthday.

There’s a surprising amount of crossover between the worlds of electronics and tattooing. We’ve featured functional temporary tattoo circuits, prison-expedient tattoo guns, and even a CNC tattoo machine.

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The Multichannel Field Recorder You Can Build Right Now

March 22, 2019 by 8 Comments

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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Introducing The Shitty Add-On V1.69bis Standard

March 20, 2019 by 45 Comments

The last few years have seen a rise of artistic PCBs. Whether these are one-off projects with a little graphic on the silkscreen or the art of manufacturing and supply chains, these fancy PCBs are here to stay. Nowhere is this more apparent than the loose confederation of Badgelife enthusiasts, a hardware collective dedicated to making expressive and impressive electronic baubles for various hacker conferences. Here, hundreds of different hardware badges are created every year. It’s electronic art, supported by a community.

Some of these badges aren’t technically badges, but rather small, blinky add-ons meant to connect to a main badge, and these add-ons are all backed by a community-derived standard. The Shitty Add-On Standard is how you put smaller PCBs onto bigger PCBs. It is supported by tens of thousands of badges, and all of the people who are spending their free time designing electronic conference badges are using this standard.

It’s been more than a year since the Shitty Add-On standard was created, and in that time the people behind the work have seen the shortcomings of the first edition of the standard. Mechanically, it’s not really that strong, and it would be neat if there were a few more pins to drive RGB LEDs. This has led to the creation of the latest revision of the Shitty Add-On Standard, V.1.69bis. Now, for the first time, this standard is ready for the world to see.

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