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

March 19, 2024 by Kristina Panos 7 Comments

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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Ancient Instrument Goes Digital: The Digi-Gurdy

March 18, 2024 by Donald Papp 12 Comments

The hurdy-gurdy is a fascinating string instrument dating from sometime around the 10th century. There is an active community of modern enthusiasts, but one can’t simply walk into a music shop and buy one. That’s where [XenonJohn] and the Digi-Gurdy come in, bringing some nice features while maintaining all the important elements of the original.

The mechanical keys and crank of the Hurdy-Gurdy are preserved in this modern digital incarnation.

The hurdy-gurdy works by droning strings with a rotating wheel, and the player applies pressure to those strings via keys to play combinations of notes. Here’s a video demonstrating what it sounds like to play one, and one can see a conceptual resemblance to bagpipes, among other things.

The Digi-Gurdy is a modern electronic version that maintains the mechanical elements while sending MIDI signals over USB. It has options for line-out or headphone output. A thriving online community has shaped its development since its inception years ago.

We hope this leaves you wanting to know more because [XenonJohn] has loads of details to share. The main website at digigurdy.com is jam-packed with information about this instrument and its construction, and the project page on Hackaday.io has more nitty-gritty design details and source files for those who crave hardware specifics.

If [XenonJohn]’s name sounds familiar, it’s because we’ve admired his work on DIY self-balancing vehicles over the years. He also submitted an earlier version as an entry into the Hackaday Prize. His careful attention to detail shines through. Check out the two videos (embedded just below the page break): the first demonstrates the Digi-Gurdy, and the second shows off the construction and insides. You’d think a MIDI hurdy-gurdy would be unique, but, actually, we’ve seen more than one.

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The Most Famous Room In Rock-n-Roll You’ve Never Seen

March 17, 2024 by Jenny List 6 Comments

The study of audio technology has a lot of fascinating branches, and one or two of them even take the curious engineer not into electronics but into architecture. There’s the anechoic chamber with its complete lack of echo, but at the other end of the scale, there’s the echo chamber.

It’s normal in 2024 when searching for reverb to reach for a software plugin, but following the effect back through silicon, spring lines, and metal plates to the 1950s, we find an echo chamber as a real room with a speaker and a microphone placed in it. [Rick Beato] takes us into the echo chamber, starting with one of the few remaining originals and probably the one whose effect has been heard on the most highly-charting music, at the famous Abbey Road studio in London.

The video below the break is broadly in two parts, with the first concentrating on the Abbey Road chamber and the second showing how an empty room in a house can be used to make your own. It’s aimed at musicians rather than hardware hackers but we think it’s one of those moments of crossover that readers might find interesting. We were particularly curious about the tall ceramic tubes in the Abbey Road chamber, designed to further break up the sound waves for a greater depth of reverb.

The video shows how reverb can be achieved with just a room, but don’t worry if you’re space limited. A plate reverb needn’t break the bank. Or, grab a spring.

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Playing Audio On The Pi Pico With No DAC To Speak Of

March 12, 2024 by Lewin Day 24 Comments

Normally, if you want to play music or other audio on a microcontroller, you need to get yourself a DAC. Or at least, that’s the easiest way to go about it and the one most likely to get you good, intelligible audio. You don’t have to go that way, though, as [antirez] demonstrates.

[antirez] decided to do this with a Pi Pico, but it’s applicable to other microcontrollers too. It’s all done with a single pin and a PWM output. The PWM output is set to a very high frequency beyond human hearing. In this case, it was 100 KHz. Then, the duty cycle of the PWM is changed to essentially output various average voltage levels at the pin. Vary the output voltage as per your desired sound file by using each sample to vary the duty cycle of the PWM. Voila! You can output whatever sound you want on that pin! [antirez] steps through the basics of doing this, including processing simple WAV files into a raw format that can be dumped into MicroPython code.

There’s no sound sample on the project page, and we’d have to assume it sounds pretty crunchy when hooked up to a speaker. And yet, it could prove a useful technique if you’re designing your own audio greeting cards or something, so keep that in mind!

This Piano Does Not Exist

March 12, 2024 by Jenny List 9 Comments

A couple of decades ago one of *the* smartphone accessories to have was a Bluetooth keyboard which projected the keymap onto a table surface where letters could be typed in a virtual space. If we’re honest, we remember them as not being very good. But that hasn’t stopped the idea from resurfacing from time to time.

We’re reminded of it by [Mayuresh1611]’s paper piano, in which a virtual piano keyboard is watched over by a webcam to detect the player’s fingers such that the correct note from a range of MP3 files is delivered.

The README is frustratingly light on details other than setup, but a dive into the requirements reveals OpenCV as expected, and TensorFlow. It seems there’s a training step before a would-be virtual virtuoso can tinkle on the non-existent ivories, but the demo shows that there’s something playable in there. We like the idea, and wonder whether it could also be applied to other instruments such as percussion. A table as a drum kit would surely be just as much fun.

This certainly isn’t the first touch piano we’ve featured, but we think it may be the only one using OpenCV. A previous one used more conventional capacitive sensors.

Ferrules And 3D Prints Revive Classic Microphone

March 8, 2024 by Dan Maloney 3 Comments

Contrary to what our readers may think, we Hackaday writers aren’t exactly hacking layabouts. True, we spend a great deal of time combing through a vast corpus of material to bring you the best from all quadrants of the hacking galaxy, but we do manage to find a few minutes here and there to dip into the shop for a quick hack or two.

Our own [Jenny List] proves that with this quick and easy vintage microphone revival. The mic in question is a Shure Unidyne III, a cardioid pattern dynamic microphone that has been made in the millions since the 1950s. She’s got a couple of these old classics that have been sidelined thanks to their obsolete Amphenol MC3M connectors. The connectors look a little like the now-standard XLR balanced connector, but the pin spacing and pattern are just a touch different.

Luckily, the female sockets in the connector are just the right size to accept one of the crimp-on ferrules [Jenny] had on hand with a snug grip. These were crimped to a length of Cat 5 cable (don’t judge) to complete the wiring, but that left things looking a bit ratty. Some quick OpenSCAD work and a little PLA resulted in a two-piece shell that provides strain relief and protection for the field-expedient connections. It’s not [Roger Daltry] secure, mind you, but as you can see in the video below the break it’s not bad — nothing a few dozen yards of gaffer’s tape couldn’t fix. Come to it, looks like The Who were using the same microphones. Small world.

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Raspinamp: It Really Replicates Questionable Activities Involving Llamas

March 7, 2024 by Bryan Cockfield 23 Comments

In the late 90s as MP3s and various file sharing platforms became more common, most of us were looking for better players than the default media players that came with our operating systems, if they were included at all. To avoid tragedies like Windows Media Center, plenty of us switched to Winamp instead, a much more customizable piece of software that helped pave the way for the digital music revolution of that era. Although there are new, official versions of Winamp currently available, nothing really tops the nostalgia of the original few releases of the software which this project faithfully replicates in handheld form.

The handheld music player uses a standard Raspberry Pi (in this case, a 3B) and a 3.5″ TFT touchscreen display, all enclosed in a clear plastic case. With all of the Pi configuration out of the way, including getting the touchscreen working properly, the software can be set up. It uses QMMP as a media player with a Winamp skin since QMMP works well on Linux systems with limited resources. After getting it installed there’s still some configuration to do to get the Pi to start it at boot and also to fit the player perfectly into the confines of the screen without any of the desktop showing around the edges.

Although it doesn’t use the original Winamp software directly, as that would involve a number of compatibility layers and/or legacy hardware at this point, we still think it’s a faithful recreation of how the original looked and felt on our Windows 98 machines. With a battery and a sizable SD card, this could have been the portable MP3 player many of us never knew we wanted until the iPod came out in the early 00s, and would certainly still work today for those of us not chained to a streaming service. A Raspberry Pi is not the only platform that can replicate the Winamp experience, though. This player does a similar job with the PyPortal instead.

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