Fabric(ated) Drum Machine

January 7, 2020 by Brian McEvoy 3 Comments

Some folks bring out an heirloom table runner when they have company, but what if you sewed your own and made it musical? We’d never put it away! [kAi CHENG] has an Instructable about how to recreate his melodic material, and there is a link to his website, which describes his design process, not just the finished product. We have a video below showing a jam session where he exercises a basic function set.

GarageBand is his DAW of choice, which receives translated MIDI from a Lilypad. If you don’t have a Lilypad, any Arduino based on the ATmega328P chip should work seamlessly. Testing shows that conductive threads in the soft circuit results in an occasional short circuit, but copper tape makes a good conductor at the intersections. Wide metallic strips make for tolerant landing pads beneath modular potentiometers fitted with inviting foam knobs. Each twist controls a loop in GarageBand, and there is a pressure-sensitive pad to change the soundset. Of course, since this is all over MIDI, you can customize to your heart’s content.

MIDI drums come in all shapes and sizes, from a familiar game controller to hand rakes.

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Drill Thrice, Solder Once

December 27, 2019 by Brian McEvoy 28 Comments

If you design printed circuit boards, then you will have also redesigned printed circuit boards. Nobody gets it right the first time, every time. Sometimes you can solder a scrap of 30gauge wire, flip a component 180°, or make a TO-92 transistor do that little pirouette thing where the legs go every-which-way. If you angered the PCB deities, you may have to access a component pad far from an edge. [Nathan Seidle], the founder of Sparkfun, finds himself in this situation, but all hope is not lost.

Our first thought is to desolder everything, then take a hot iron and tiny wires to each pad. Of course, this opens up a lot of potential for damage to the chip, cold joints, and radio interference. Accessing the pin in vivo has risks, but they are calculated. The idea is to locate the pin, then systematically drill from the backside and expose the copper. [Nate] also discovers that alcohol will make the PCB transparent so you can peer at the underside to confirm you have found your mark.

In a real, “fight fire with fire” idea, you can rework with flex PCBs or push your PCB Fu to the next level and use PCBs as your enclosure.

Bottle Organ Breakdown

December 14, 2019 by Brian McEvoy 8 Comments

A keen-eyed commenter pointed us to a homemade bottle organ that plays like a piano. The complexity gets turned up with foot-powered bellows and custom keys, but the magic of [Mike] and [Simon Haisell]’s garage-built instrument is not lost in the slightest. We also have the video below the break and there is a bottle organ performance by [Coyote Merlot].

The working concepts are explained well in the video, and that starts with the bellows. In the first few seconds of the video, we see an organist swaying as he plays, and it would be accurate to say the music moves him. The wobbling is to pedal a couple of levers that squeeze a pair of air sacs and slide under wheels that look like a hardware store purchase. The spring-return mechanism is a repurposed bungee cord and you know we dig that kind of resourcefulness. Each bellow valve is made with traditional leather flaps of the type that predate bungee cords and camera phones. These air pumps inflate a big reservoir in the back that provides continuous pressure to a manifold where each of the thirty-six keys control a valve responsible for one bottle. The pair built every wooden part we mentioned with the explicit purpose of creating this organ.

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In Case You Cannot Make It To An Escape Room

November 27, 2019 by Brian McEvoy 17 Comments

Escape rooms are awesome for people who like to solve puzzles, see how things work, or enjoy a mystery. Everyone reading this falls into at least one of those categories. We enjoy puzzles and mysteries, but we have a fondness for seeing how things work. To this end, we direct your attention to [doktorinjh]’s “Bomb Disarming Puzzle in a Suitcase” Game, which is a mysterious puzzle box he built himself. I guess the mystery is mostly in the gameplay, which you can watch below because he shows us his build photos and describes the hardware inside.

At its heart is an Arduino Mega, a wise choice since our back-of-the-napkin estimation puts his I/O count over forty-five and the Mega can handle them all with a few pins to spare. Working inside the confines of a briefcase came with its own challenges, but we adore the way he used the hexagon theme in the top panel to allow for knob clearance. It was so subtle that we almost missed it.

The escape room theme is delightful, and we appreciate the mix of games, aesthetics, and techno-trickery in many forms.

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Everything Makes Sound If You Try Hard Enough

October 11, 2019 by Brian McEvoy 8 Comments

Speaker cone materials can be a deep rabbit hole ranging from inexpensive paper to kevlar. We’ve all cut apart, or blown out, the cheapies to see their inner workings, but the exotic material list does not stop at audiophile-quality models. It can include mirrors, microwave ovens, and a European hacker’s forehead. Video also after the break. In addition to the speakers with expensive elements, there are sound-generating transducers with no cones. These are sometimes called surface speakers, and they vibrate something, anything, to make a sound. At their cores, they have many of the same parts, and making a surface speaker from a traditional speaker is not difficult.

The first step is to find a raw speaker, one with no crossover components, possibly from a garage sale or from a set your spouse insists are outdated, ugly, and better off as firewood. Power specifications should not change since we will be using the same solenoid, and that means your amplifier can follow the speakers back from the dead. The video provides step-by-step instructions, and the goal is to create a module with a moving shaft, but the range must be limited so it cannot be pushed back into the speaker or pulled away, both could destroy it. Once you have that, go around and make everything noisy. Don’t use this on pets or children, but spouses are fair game.

We would love to see a chip bender experiment with different speaker mediums to add an extra layer of complexity, but for the rest of us, bone conduction is already a real thing, and if you enjoy impractical speakers, you are not the only one with your head in the clouds.

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Entombed Secrets Partially Unearthed As Researchers Dissect Clever Maze-Generating Algorithm

September 30, 2019 by Brian McEvoy 23 Comments

If you look at enough of another developer’s code, you will eventually say, “What were you thinking, you gosh-darn lunatic?” Now, this exchange can precede the moment where you quit a company and check into a padded room, or it can be akin to calling someone a mad genius and offering them a beer. In the case of [Steven Sidley]’s 1982 game Entombed, [John Aycock] and [Tara Copplestone] found a mysterious table for generating pseudo-random mazes and wrote a whitepaper on how it all works (PDF). The table only generates solvable mazes, but if any bits are changed, the puzzles become inescapable.

The software archaeologists are currently in a labyrinth of their own, in which the exit is an explanation of the table, but the path is overgrown with decade-old vines. The programmer did not make the table himself, and its creator’s name is buried somewhere in the maze. Game cart storage was desperately limited so mazes had to be generated on-the-fly rather than crafted and stored. Entombed‘s ad-hoc method worked by assessing the previous row and generating the next based on particular criteria, with some PRNG in places to keep it fresh. To save more space, the screen was mirrored down the center which doubles the workload of the table. Someday this mysterious table’s origins may be explained but for now, it is a work of art in its own right.

Aside from a table pulled directly from the aether, this maze game leaned on pseudo-random numbers but there is room for improvement in that regard too.

Via BBC Future.

Pegleg: Raspberry Pi Implanted Below The Skin (Not Coming To A Store Near You)

August 29, 2019 by Brian McEvoy 88 Comments

Earlier this month, a group of biohackers installed two Rasberry Pis in their legs. While that sounds like the bleeding edge, those computers were already v2 of a project called PegLeg. I was fortunate enough to see both versions in the flesh, so to speak. The first version was scarily large — a mainboard donated by a wifi router roughly the size of an Altoids tin. It’s a reminder that the line between technology’s cutting edge and bleeding edge is moving ever onward and this one was firmly on the bleeding edge.

How does that line end up moving? Sometimes it’s just a matter of what intelligent people can accomplish in a long week. Back in May, during a three-day biohacker convention called Grindfest, someone said something along the lines of, “Wouldn’t it be cool if…” Anyone who has spent an hour in a maker space or hacker convention knows how those conversations go. Rather than ending with a laugh, things progressed at a fever pitch.

The router shed all non-vital components. USB ports: ground off. Plastic case: recycled. Battery: repurposed. Amazon’s fastest delivery brought a Qi wireless coil to power the implant from outside the body and the smallest USB stick with 64 GB on the silicon. The only recipient of PegLeg version 1.0 was [Lepht Anonym], who uses the pronoun ‘it’. [Lepht] has a well-earned reputation among biohackers who focus on technological implants who often use the term “grinder,” not to be confused with the dating app or power tool.

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