Musical Robot Lets You Play The Recorder Hands-Free

May 29, 2023 by Robin Kearey 6 Comments

Although many people might remember the recorder as just a simple instrument from their introductory music classes, it can nevertheless produce rich and varied melodies in the hands of a virtuoso like Frans Brüggen. [Luis Marx] also took music lessons as a child, but never progressed much beyond an elementary level. Instead, he preferred to spend his time honing his engineering skills, which eventually enabled him to get back into music.

Initially, he wanted to build a piano-playing exoskeleton, to marionette his fingers up and down the ivories, but had to bail on that one because of the insane complexity. So instead, he built himself a robot that helps him play the recorder. (Video, in German, embedded below, fast-forwarded to the recorder part.)

A recorder has eight finger holes, which can be covered or uncovered in various combinations to produce tones. [Luis] therefore used eight solenoids, mounted on a 3D-printed frame, to actuate the finger holes. The basic idea worked, but getting the solenoids to fully cover the holes each time turned out to be a challenge: even a slight misalignment would cause air to leak past the plug and produce a horrible off-key sound.

After a lot of trial and error, [Luis] found foam earplugs to be a pretty good material for emulating human fingertips. He also discovered that relying on the solenoids’ spring tension to keep the holes closed was not reliable; a better solution was to flip the solenoids around and use the much larger force from their powered stroke to create an air-tight seal.

The solenoids are driven by an Arduino Nano through a set of MOSFET modules, powered by a lithium battery. [Luis] wrote some Arduino sketches with famous melodies like Beethoven’s Für Elise, which sound quite decent on the robo-recorder: perhaps not on Frans Brüggen’s level, but pretty impressive for a self-declared “music noob” like [Luis].

Many robotic musicians play instruments like pianos or xylophones. Instruments from the flute family are harder to automate, but it has been done before. We’ve even seen a MIDI-powered harmonica.

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Replace Your Automatic Transmission With A Bunch Of Relays

January 5, 2023 by Dan Maloney 80 Comments

A “Check Engine” light on your dashboard could mean anything from a loose gas cap to a wallet-destroying repair in the offing. For [Dean Segovis], his CEL was indicating a fairly serious condition: a missing transmission. So naturally, he built this electronic transmission emulator to solve the problem.

Some explanation may be necessary here. [Dean]’s missing transmission was the result of neither theft nor accident. Rather, he replaced the failed automatic transmission on his 2003 Volkswagen EuroVan with a manual transmission. Trouble is, that left the car’s computer convinced that the many solenoids and sensors on the original transmission weren’t working, leaving him with a perfectly serviceable vehicle but an inspection-failing light on the dash.

To convince the transmission control module that a working automatic was still installed and clear the fourteen-odd diagnostic codes, [Dean] put together a block of eight common automotive relays. The relay coils approximate the resistance of the original transmission’s actuators, which convinces the TCU that everything is hunky dory. There were also a couple of speed sensors in the transmission, which he spoofed with some resistors, as well as the multi-function switch, which detects the shift lever position. All told, the emulator convinces the TCU that there’s an automatic transmission installed, which is enough for it to give the all-clear and turn off the Check Engine light on the dash.

We love hacks like this, and hats off to [Dean] for sharing it with the VW community. Apparently the issue with the EuroVan automatic transmissions is common enough that a cottage industry has developed to replace them with manuals. It’s not the only questionable aspect of VW engineering, of course, but this could help quite a few people out of a sticky situation.

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Love Is A Burning Flame, And So Is This Underwater Burning Ring Of Fire

July 29, 2022 by Ryan Flowers 22 Comments

When Johnny Cash wrote “Ring of Fire”, he was talking about love. But when an unnamed follower of [TheBackyardScientist] took it literally and suggested making actual rings of fire — underwater — they rose to the challenge as you can see in the video below the break.

Of course there are several ingredients to underwater fire rings. First you need water, and a pool clearly does the job in this video. Second, you need flammable rings of gas. [TheBackyardScientist] decided to build a machine to create the gas rings, and it’s quite interesting to see them go through several iterations before settling on a voice coil based poppet valve design. We must say that it works absolutely swimmingly.

Lastly there needs to be fire. And for fire, you need something flammable, and something shocking. Forty thousands volts light up a spark plug, even underwater. The fuel is provided by what appears to be compressed air and acetylene but we’re not 100% sure. We are sure that it goes bang! quite sufficiently, as demonstrated by its aptitude for blowing things up.

We appreciated the engineering that went into the project but also the rapid iterations of ideas, the overcoming of serious obstacles and the actual science that went into the project. Even if it is just randomly making literal burning rings of fire.

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A wooden xylophone with electronic contraptions for robotic playback

Robotic Xylophone Makes Music With MIDI Magic

January 27, 2022 by Chris Wilkinson 8 Comments

The MIDI format has long been used to create some banging electronic music, so it’s refreshing to see how [John P. Miller] applied the standard in his decidedly analog self-playing robotic xylophone.

Framed inside a fetching Red Oak enclosure, the 25-key instrument uses individual solenoids for each key, meaning that it has no problem striking multiple bars simultaneously. This extra fidelity really helps in reproducing the familiar melodies via the MIDI format. The tracks themselves can be loaded onto the device via SD card, and selected for playback with character LCD and rotary knob.

The software transposes the full MIDI music spectrum of a particular track into a 25-note version compatible with the xylophone. Considering that a piano typically has 88 keys, some musical concessions are needed to produce a recognizable playback, but overall it’s an enjoyable musical experience.

Perhaps most remarkable about this project is the documentation. If you want to build your own, everything you need to know is available online, and the no-solder approach makes this project very accessible. Most of the write-up happened some years ago, and we’re really interested to see what improvements have been made since.

The robotic xylophone is reminiscent of these automatic tubular bells from some time ago. These musical hacks can be particularly inspiring, and we can’t wait to see more.

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Get Down To Some African Tunes With This HomeBrew Synth

December 5, 2021 by Dave Rowntree 9 Comments

~~South African~~ [Afrorack] claims to have built the first home-built modular synthesiser in Africa. Whilst we can’t be sure of this (and to be frank, it doesn’t actually matter) what we can be sure of is that the latest additions to this rig sound pretty rad. (video, embedded below) There really isn’t much doubt that the African nations are the kings of rhythm, and that living in the less well-to-do areas you need to have a certain resourcefulness to use the materials around you. It’s not like you can just pop down to the local electronics store for a missing part, even if you had the funds for it.

The modular synth looks pretty nice, rough and ready like a real homebrew, and the use of an oil can as a bass drum and rice in a plastic skiff as an instrument might look crude, but sound pretty good. All three additions to the rig are simple spring-loaded solenoid affairs, but since off the shelf stuff is an expensive luxury, hand wound coils were in order. With a bobbin formed with a metal rod and two suitably trimmed fanta bottle lids, a wire spool holder sitting on what looks like a cake stand, a drill powered coil winder was constructed. We did smirk a little when in an early shot, wire was guided by hand, which was rapidly followed by an adjustment to guiding with a rag. Darn friction burns! We’re watching this with interest to see what the next additions will be, but for now, just sit back and nerd out to some sick African techno tunes!

Want to see a mess-o-wires turn into something meaningful? Got some Game Boys lying around needing something to do? How about a chiptune synth?

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A man using a homemade vacuum apparatus to climb a wall

Scale Buildings With The Power Of Suction

November 28, 2021 by Chris Wilkinson 30 Comments

Walls can’t hold [Elijah Cirioli]. The would-be superhero has been busy scaling the sides of buildings using his self-contained vacuum climbers. (Video embedded after the break.)

After being inspired by the winning project of an Air Force design challenge, our plain-clothed crusader got to work on a pair of prototype vacuum climbers. The wooden prototypes were an unexpected success, so work soon began on the models featured in the video after the break. The main improvements in this second version included using ¼ inch acrylic instead of plywood, as well as an improved gasket for a better seal against the imperfect exterior of many building walls.

While the system would still ultimately struggle with brick walls (and other imperfect surfaces), it performs more than adequately when ascending smoother concrete walls. And while the acrylic was a far better choice than the plywood, one of the acrylic panels still developed a fracture. Even so, the results speak for themselves, and we have to applaud the inventor’s seemingly unconditional trust in his equipment.

We haven’t seen a follow-up from [Elijah Cirioli] recently, so here’s hoping that he’s busy working on version three, and that he’s not stuck up a wall somewhere. In the meantime, check out how someone accomplished similar wall-climbing feats using salvaged microwave transformers.

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Fake motivational plant squirts you in the wherever.

Focus Flower Motivates By Squirting Water In Your Face

November 4, 2021 by Kristina Panos 4 Comments

When you need to get some tasks done and are short on attention, it’s hard to beat a timer. But whenever you do, it feels pretty darn good. The problem is that when you don’t finish in time, what’s the punishment? There are no consequences baked into the Pomodoro Technique other than good ol’ guilt. Wouldn’t it be better if there was a bit of negative reinforcement involved?

[Hardware Unknown]’s Focus Flower never needs watering, at least not in the normal horticultural way. You will have to fill a reservoir, because this flower provides liquid motivation. No, it’s not a spirit spritzer, though we suppose you could turn it into an avant-garde vodka fountain when the novelty of water wears off, making this Pomodoro with a twist into more of a Bloody Mary. It’s a natural next step, especially if you were already into the hot sauce idea.

Operation Focus Flower is simple: just push the easy button to start the task timer, and the Arduino Nano attached will begin a countdown. Push the button again when you’re done, but if you don’t do it before the countdown is over, the plant squirts you with a steady, skin-blasting stream of water from a solenoid-driven flosser tip. An air compressor nearby is required, which blows the minimalist vibe a bit, but you could always stow that part underneath your desk.

The Focus Flower sure looks to be effective at the whole negative reinforcement thing. And it doesn’t leave you totally clueless — there’s a ring of LEDs around the base that show how much time is left. Whenever you do successfully hit the button in time, it will say ‘that was easy’ in one of 12 languages, hence all the flags. Do not miss the totally free infomercial below.

Maybe you want a more friendly way to manage your time — we understand. Meet the Pomodachi productivity pet.

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