2024 Home Sweet Home Automation: A Piano-Controlled Smart Home

There’s a scene in Willy Wonka and the Chocolate Factory where a little flap in the wall flips down to reveal a small organ embedded there. Gene Wilder plays a bit of Rachmaninoff on the organ, and the giant door to the chocolate room slowly creaks open.

Once [Nathan Orick] got this into his head, he couldn’t get it out, and had to give it a go in his own home. Regrettably there’s no chocolate rooms in the house, so he’s using various chords and melodies to do things like control the lights and the TV, as you’ll see in the video after the break. Although this one may have started as a joke of a home automation scheme, [Nathan] thinks it turned out pretty solid, and so do we.

He already had the piano and a Raspberry Pi Zero lying around, so getting this up and running was mostly about connections and code. Speaking of connections, [Nathan] was hard-pressed to find a micro-USB to USB-B cord, so he ended up splicing one together. Simple enough. The harder part was getting Linux to recognize the keyboard, but all it took was touching all the pins with a multimeter, evidently. What’s a project without a little magic?

And not only did it show up, Linux went to the trouble of registering it as a MIDI device all on its own. Once [Nathan] obtained the port number, he had data printing to the console every time he played a note. Then it was mostly a matter of writing code to interact with MIDI data and track the notes as they’re played, and put it all together with Home Assistant. Be sure to check out the brief demo after the break.

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Less Rock, More Roll: A MIDI Barrel Piano

Strolling around a park, pedestrian zone, or tourist area in any bigger city is rarely complete without encountering the sound of a barrel organ — the perfect instrument if arm stamina and steady rotation speed are your kind of musical skills. Its less-encountered cousin, and predecessor of self-playing pianos, is the barrel piano, which follows the same playing principle: a hand-operated crank rotates a barrel, and either pins located on that barrel, or punched paper rolls encode the strings it should pluck in order to play its programmed song. [gabbapeople] thought optocouplers would be the perfect alternative here, and built a MIDI barrel piano with them.

Keeping the classic, hand-operated wheel-cranking, a 3D-printed gear mechanism rolls a paper sheet over a plexiglas fixture, but instead of having holes punched into it, [gabbapeople]’s piano has simple markings printed on them. Those markings are read by a set of Octoliner modules mounted next to each other, connected to an Arduino. The Octoliner itself has eight pairs of IR LEDs and phototransistors arranged in a row, and is normally used to build line-following robots, so reading note markings is certainly a clever alternative use for it.

Each LED/transistor pair represents a dedicated note, and to prevent false positives from neighboring lines, [gabbapeople] 3D printed little collars to isolate each of the pairs. Once the signals are read by the Arduino, they’re turned into MIDI messages to send via USB to a computer running any type of software synthesizer. And if your hands do get tired, you can also crank it with a power drill, as shown in the video after the break, along with a few playback demonstrations.

It’s always fun to see a modern twist added to old-school instruments, especially the ones that aren’t your typical MIDI controllers, like a harp, a full-scale church organ, or of course the magnificently named hurdy-gurdy. And for more of [gabbapeople]’s work, check out his split-flip weather display.

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Pulling Music Out Of Thin Air With A Raspberry Pi

Pianos are great instruments, but being rather heavy and requiring a fair amount of space they are certainly not known for their convenience. Sure, there are more portable varieties available, but they rarely resemble the elegance and classiness of a grand piano. One option is of course to build a downscaled version yourself — and since you’re already customizing the instrument, why stop at the way you play it. [2fishy] didn’t stop there either and ended up with a wooden, space friendly, light controlled piano housing a Raspberry Pi.

Inspired by the concept of a laser harp, [2fishy] followed the same principle but chose a simpler and safer alternative by using LEDs instead. For each playable tone, a LED is mounted opposite a light dependent resistor, creating an array of switches that is then connected to the Raspberry Pi’s GPIO pins. A Python script is handling the rest, polling the GPIO states and — with a little help from pygame, triggering MIDI playback whenever the light stream is interrupted.

There are enough LED/LDR pairs to play one full octave and have some additional control inputs for menu and octave shifting. This concept will naturally require some adjustments to your playing — you can get an idea of it in the demonstration video after the break. And if this design is still not the right size for you, or if you prefer to play in total darkness, this similar MIDI instrument using ultrasonic distance sensors could be of interest.

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Wireless MIDI Floor Piano!

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[Jianan Li] just finished documenting one of his most recent projects, a wireless MIDI floor piano that he and a small group made for Duke University’s Hackathon!

He was inspired to do this project after reading our recent coverage on a DIY Pressure Plate. Having only 24 hours to compete in the Hackathon, they had to choose something that was fairly easy to build out of cheap materials, and quick to assemble. This was just the ticket.

The piano features 25 of the aluminum foil pressure plates, whose state are read by the Arduino Mega. This is then transmitted by an XBee radio to an Arduino Uno, which acts as the receiver for the laptop that processes the signals. They even added a remote control using an ATtiny85 to allow for octave and instrument changes — it also uses an XBee to communicate back to the Uno. For a 24 hour build, the quality is quite impressive, and it doesn’t sound half bad either — Take a listen after the break!

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