Researchers at Google have posed themselves an interesting problem to solve: mastering the piano. However, they’re not trying to teach themselves, but a pair of simulated anthropomorphic robotic hands instead. Enter RoboPianist.
The hope is that the RoboPianist platform can help benchmark “high-dimensional control, targeted at testing high spatial and temporal precision, coordination, and planning, all with an underactuated system frequently making-and-breaking contacts.”
If that all sounds like a bit much to follow, the basic gist is that playing the piano takes a ton of coordination and control. Doing it in a musical way requires both high speed and perfect timing, further upping the challenge. The team hopes that by developing control strategies that can master the piano, they will more broadly learn about techniques useful for two-handed, multi-fingered control. To that end, RoboPianist models a pair of robot hands with 22 actuators each, or 44 in total. Much like human hands, the robot hands are underactuated by design, meaning they have less actuators than their total degrees of freedom.
The PiezoPiano is a single PCB device with a ATmega4809 running the show. It has eight buttons and eight piezo transducers that give you just one octave’s range on the keyboard. Truth be told, that’s only in one scale; you’re not getting the whole twelve tones of flats and sharps included. And, when we say keyboard, we really mean “tactile buttons.” You get the drift. It’s all assembled in a cute enclosure mimicking the shape of a real grand piano.
Fundamentally, it’s a cute little musical desktoy that reminds us greatly of the Stylophone. Impressively, though, those eight buzzers mean it has eight-note polyphony. That’s nothing to sniff at compared to all the monophonic synths out there. It’s also available on Tindie if you’d like to buy a kit off the shelf. Video after the break.
A first attempt with an upright piano failed quickly. After just four minutes submerged in water, the wooden hammers would seize up as they swelled with moisture.
A grand piano was sourced for a second attempt. The strings were first detensioned to make things easier to work with, and the internal frame pried out from the surrounding piano body. To stop the water pouring out past the keys and strings, a simple solution was implemented: tilting the piano up so the water remained in the body below. A judicious application of various sealing agents was then used to seal the frame. Amazingly, the best information on sealing a piano came from enthusiasts building aquariums out of plywood boxes. Go figure.
The water has a muting effect on the piano’s sound as you might expect. The sound is particularly compelling when heard via underwater mics placed in the water-filled cavity. It almost sounds like a plucked instrument, and gives everything a strangely maritime feel. The sound waves can be seen on the surface of the water, too.
The experiment came to a tragic end when the piano was overfilled, dumping water over the keys and hammers. This caused every key to jam, killing the piano for good.
It’s a fun build, and a very silly one, if you can stand to watch a piano treated in this way. [Mattias] has form in the area of oddball instrument hacks, too, as we’ve previously featured his helium guitar. Video after the break.
Despite being a computer with some extra chips, synthesizers today are still quite expensive. They used to cost far more, but we tend to think of them as instruments instead of computers. And just because it is an instrument doesn’t mean someone like [Peter Sobot] can’t crack it open and patch the OS inside.
The synth in question is a Kurzweil K2500, released in 1996 with a Motorola 68000. Rather than directly start pulling out parts on the kitchen table, [Peter] began by doing some online research. The K2500 operating system is still available online, and a quick pass through Ghidra showed some proper instructions, meaning the file likely wasn’t encrypted.
He found the part of the code that reads in a new firmware file and checks the header and checksum. Certain functions were very high in memory, and a quick consultation of the service manual yielded an answer: it was the volatile RAM. With that tidbit, [Peter] was able to find the function that copied chunks of the new ROM file to RAM and start decoding the file correctly. [Peter] changed a few strings, made sure the checksums were correct, and he was ready to flash. The actual tweaks that [Peter] are made are left up to the reader, but the techniques to get a working decompiled build and a viable ROM image to flash apply to many projects. One benefit is now the K2000 simulates correctly in MAME due to his spelunking. He has his flashing script up on GitHub for the curious.
[Stanislaw Pusep] has gifted us with the Pianolizer project – an easy-to-use toolkit for music exploration and visualization, an audio spectrum analyzer helping you turn sounds into piano notes. You can run his toolkit on a variety of different devices, from Raspberry Pi and PCs, to any browser-equipped device including smartphones, and use its note output however your heart desires. To show off his toolkit in action, he set it up on a Raspberry Pi, with Python code taking the note data and sending color information to the LED strip, displaying the notes in real time as he plays them on a MIDI keyboard! He also created a browser version that you can use with a microphone input or an audio file of your choosing, so you only need to open a webpage to play with this toolkit’s capabilities.
[Stanislaw] also documented the principles behind the code, explaining how the note recognition does its magic in simple terms, yet giving many insights. We are used to Fast Fourier Transform (FFT) being our go-to approach for spectral analysis, aka, recognizing different frequencies in a stream of data. However, a general-purpose FFT algorithm is not as good for musical notes, since intervals between note frequencies become wider as frequency increases, and you need to do more work to distinguish the notes. In this toolkit, he used a Sliding Discrete Fourier Transform (SDFT) algorithm, and explains to us how he derived the parameters for it from musical note frequencies. In the end of the documentation, he also gives you a lot of useful references if you would like to explore this topic further!
The core ethos of “hacking” is usually interpreted as modifying something for a use that it wasn’t originally built for. Plenty of builds are modifications or improvements on existing technology, but sometimes that just isn’t enough. Sometimes we have to go all the way down and build something completely from scratch, and [Balthasar]’s recent piano-like musical instrument fits squarely into this category.
This electronic keyboard is completely designed and built from scratch, including the structure of the instrument and the keys themselves. [Balthasar] made each one by hand out of wood and then built an action mechanism for them to register presses. While they don’t detect velocity or pressure, the instrument is capable of defining the waveform and envelope for any note, is able to play multiple notes per key, and is able to change individual octaves. This is thanks to a custom 6×12 matrix connected to a STM32 microcontroller. Part of the reason [Balthasar] chose this microcontroller is that it can do some of the calculations needed to produce music in a single clock cycle, which is an impressive and under-reported feature for the platform.
With everything built and wired together, the keyboard is shockingly versatile. With the custom matrix it is easy to switch individual octaves on the piano to any range programmable, making the 61-key piano capable of sounding like a full 88-key piano. Any sound can be programmed in as well, further increasing its versatility, which is all the more impressive for being built from the ground up. While this build focuses more on the electronics of a keyboard, we have seen other builds which replicate the physical action of a traditional acoustic piano as well.
It’s a truth universally acknowledged that sometimes a little music can add much to a nice afternoon picnic. It’s also well-known that meat cooked over hot coals should be turned regularly to allow for even cooking. This barbecue grille project from [Handy Geng] delivers on both counts.
The project uses a full 88 motors, activated by pressing keys on an electronic piano. The technique used is simple; rather than interface with the keyboard electronically or over MIDI, instead, a microswitch is installed under each individual key.
Thus, when the piano keys are pressed, the corresponding motors are switched on. Each motor turns a skewer loaded with meat, sitting above a box of hot coals. Thus, playing the piano turns the meat, allowing it to be cooked on all sides without burning.
As a further bonus, the entire piano barbecue grille is also motorized, allowing [Handy Geng] to do laps around his workshop while playing the piano and cooking up lunch. It’s a great way to cook up some grilled kebabs while simultaneously entertaining one’s guests.
We’ve seen some other fun grill hacks too – even robotic ones! Video after the break.