Imitating Art In Life With A Reverse-Engineered Tattoo

March 23, 2019 by Dan Maloney 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 Brian Benchoff 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 Brian Benchoff 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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3D-Printed Rotary Dial Keypad Is Wonderfully Useless

March 13, 2019 by Dan Maloney 10 Comments

Right up front, let us stipulate that we are not making fun of this project. Even its maker admits that it has no practical purpose. But this 3D-printed Commodore-style rotary dial keypad fails to be practical on so many levels that it’s worth celebrating.

And indeed, celebrating deprecated technology appears to be what [Jan Derogee] had in mind with this build. Rotary dials were not long ago the only way to place a call, and the last time we checked, pulse dialing was still supported by some telephone central office switchgear. Which brings us to the first failure: with millions of rotary dial phones available, why build one from scratch? [Jan] chalks it up to respect for the old tech, but in any case, the 3D-printed dial is a pretty good replica of the real thing. Granted, no real dial used a servo motor to return the dial to the resting state, but the 3D-printed springs [Jan] tried all returned the dial instantly, instead of the stately spin back that resulted in 10 pulses per second. And why this has been done up VIC-20 style and used as a keypad for Commodore computers? Beats us. It had to be used for something. That the software for the C-64 generates DTMF tones corresponding to the number dialed only adds to the wonderful weirdness of this. Check out the video below.

We’ll hand it to [Jan], he has a unique way of looking at the world, especially when it comes to clocks. We really enjoyed his persistence of phosphorescence clock, and his screw-driven linear clock turns the standard timekeeping UI on its head.

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The Bakery That Runs On Emacs

March 6, 2019 by Rich Hawkes 23 Comments

When it comes to managing ingredients and baking at a professional bakery, we know that most people would turn to an SQL database and emacs. Really, what else do you need? Okay, so maybe there are a few who would think that emacs couldn’t help you with this, so, here’s how [Piers] uses emacs and PostgresSQL to manage the day to day needs at his bakery.

[Piers] had tried a spreadsheet to keep track of things, but didn’t really like it when he had to create a new recipe: “lots of tedious copying, pasting and repetition of formulae” is how he put it. As a ex-professional programmer, [Piers] was familiar with emacs and so set up a daily worksheet in emacs using org-mode. Each morning he runs org-capture to create the template for the day’s work. Some code in the org file (run with org-babel) can run a query on the database. He’s created some code to set up each day’s journal entry and to run the complicated database queries that he needs.

There is a list of things that [Piers] is working on next, including ingredient order management and accounting, but it works for him. And to stop any potential flame wars that might break out, it’s good to mention that the system does just that: It works for him. There are other possibilities. Take a look at Al’s Editor Wars article, or Elliot’s rebuttal, or, ignore the wars and read this article on baking with steam.

Door Springs And Neopixels Demonstrate Quantum Computing Principles

March 6, 2019 by Dan Maloney 7 Comments

They may be out of style now, and something of a choking hazard for toddlers, but there’s no denying that spring doorstops make a great sound when they’re “plucked” by a foot as you walk by. Sure, maybe not on a 2:00 AM bathroom break when the rest of the house is sleeping, but certainly when used as sensors in this interactive light show.

The idea behind [Robin Baumgarten]’s “Quantum Garden” is clear from the first video below: engaging people through touch, sound, and light. Each of the 228 springs, surrounded by a Neopixel ring, is connected to one of the 12 inputs on an MPR121 capacitive touch sensor. The touch sensors and an accelerometer in the base detect which spring is sproinging and send that information to a pair of Teensies. A PC then runs the simulations that determine how the lights will react. The display is actually capable of some pretty complex responses, including full-on games. But the most interesting modes demonstrate principles of quantum computing, specifically stimulated Raman adiabatic passage (STIRAP), which describes transfers between quantum states. While the kids in the first video were a great stress test, the second video shows the display under less stimulation and gives a better idea of how it works.

We like this because it uses a simple mechanism of springs to demonstrate difficult quantum concepts in an engaging way. If you need more background on quantum computing, [Al Williams] has been covering the field for a while. Need the basics? Check out [Will Sweatman]’s primer.

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Reverse Engineering Keeps Keck Telescopes On Track

February 26, 2019 by Dan Maloney 13 Comments

Perched atop a dormant volcano far above the roiling tropical air of the Big Island of Hawai’i sit two of the largest optical telescopes in the world. Each 10-meter main mirror is but a single part of a magnificent machine weighing in at some 400 tons that needs to be positioned with incredible precision. Keeping Keck 1 and Keck 2 in peak operating condition is the job of a team of engineers and scientists, so when the servo amplifiers running the twelve motors that move each scope started to show their age, [Andrew] bit the bullet and rebuilt the obsolete boards from scratch.

The Keck telescopes were built over three decades ago, and many of the parts, including the problematic servo amps, are no longer made. Accumulated wear and tear from constant use and repeated repairs had taken their toll on the boards, from overheated components to lifted solder pads. With only some barely legible schematics of the original amplifiers to go by, [Andrew] reverse engineered new amps. Some substitutions for obsolete components were needed, the PCB design was updated to support SMD parts, and higher-quality components were specified, but the end result is essentially new amplifiers that are plug-in replacements for the original units. This should keep the telescopes on track for decades to come.

Not to sound jealous, but it seems like [Andrew] has a great gig. He’s shared a couple of his Keck adventures before, like the time a failed LED blinded the telescope. He’s also had a few more down-to-earth hacks, like fixing a dodgy LCD monitor and making spooky blinkeneyes for Halloween.