Dial Up A Tune On The Jukephone

October 10, 2023 by Kristina Panos 9 Comments

What do you do when you find a nice corded phone with giant buttons out in the wild? You could pay $80/month for a landline, use a VOIP or Bluetooth solution instead, or do something a million times cooler and turn it into a jukebox.

Now when the receiver is lifted, [Turi] hears music instead of a dial tone or a voice on the other end. But playback isn’t limited to the handset — there’s a headphone jack around back.

To listen to a track, he can either dial one in directly, or call up a random track using one of the smaller buttons below. A handy directory organizes the tunes by the hundreds, putting children’s tracks between 1-99 and the intriguing category “hits” between 900-999.

The phone’s new guts are commanded by a Raspberry Pi Pico, which is a great choice for handling the key matrix plus the rest of the buttons. As you may have guessed, there’s an DF Player Mini mp3 player that reads the tracks from an SD card. Everything is powered by a rechargeable 18650 battery.

Jukephone is open source, and you’ll find more pictures on [Turi]’s blog post. Be sure to check out the very brief build and demo video after the break.

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Auto Xylophone Uses Homemade Solenoids

October 8, 2023 by Al Williams 26 Comments

Want to play the xylophone but don’t want to learn how? [Rachad]’s automatic xylophone might be just the ticket. It uses homemade solenoids to play tunes under computer control. Think of it as a player piano but with electromagnetic strikers instead of piano keys. You can hear the instrument in action in the video below.

Since the project required 24 solenoids, [Rachad] decided to build custom ones using coils of wire and nails. We were amused to see a common curling iron used as an alternate way to apply hot glue when building the coils. The other interesting part of the project was the software. He now uses a toolchain to convert MIDI files into a serial output read by the Arduino. Eventually, he wants to train an AI to read sheet music, but that’s down the road, apparently.

Honestly, we were a bit surprised that it sounded pretty good because we understand that the material used to strike the xylophone and the exact position of the strike makes a difference. We doubt any orchestra will be building one of these, but it doesn’t sound bad to us.

The last one of these we saw did have more conventional strikers if you want to compare. Honestly, we might have just bought the solenoids off the shelf but, then again, we don’t make our own relays either.

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Playing The Guitar Of DOOM

October 7, 2023 by Kristina Panos 7 Comments

Over the years, we’ve seen DOOM run on pretty much everything from an 8088 to a single keycap. We’ve also written up one or two controllers, but we don’t think we’ve ever seen anything like this — playing DOOM with an electric guitar.

The guitar in question is a Schecter Hellraiser Deluxe, which seems like a great choice to us. In order to get the notes to control the game, [DOS Storm] converted a handful of notes to MIDI using a VST plugin called Dodo MIDI 2 and the Reaper DAW. Then it was a matter of converting MIDI to keystrokes. This took two programs — loopMIDI to do take the MIDI data and route it elsewhere, and MIDIKey2Key to actually convert the MIDI to the keystrokes that control DOOM.

The result is that the notes that move Doomguy around are mostly in an A-major bar chord formation, with some controls up in the solo range of the fret board. Be sure to check out the demo video below and watch [DOS Storm] clear level one in a fairly impressive amount of time, considering their controller is a guitar.

That key cap isn’t even the most ridiculous thing we’ve seen DOOM running on. It’s probably a toss-up between that and the LEGO brick.

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Just What Is Tone, In A Microphone?

October 5, 2023 by Jenny List 23 Comments

As long-time Hackaday readers will know, there is much rubbish spouted in the world of audio about perceived tone and performance of different hi-fi components. Usually this comes from audiophiles with, we’d dare to suggest, more money than sense. But oddly there’s an arena in which the elusive tone has less of the rubbish about it and it in fact, quite important. [Jim Lill] is a musician, and like all musicians he knows that different combinations of microphones impart a different sound to the recording. But as it’s such a difficult property to quantify, he’s set out to learn all he can about where the tone comes from in a microphone.

He’s coming to this from the viewpoint of a musician rather than an engineer, but his methodology is not diminished by this. He’s putting each mic on test in front of the same speaker at the same position, and playing a standard piece of music and a tone sweep through each. He doesn’t have an audio analyser, reference speaker and microphone, or anechoic chamber, so he’s come up with a real-world standard instead. He’s comparing every mic he can find with a Shure SM57, the go-to general purpose standard in the world of microphones for as long as anyone can remember, being a 1960s development of their earlier Unidyne series. His reasoning is that while its response is not flat the sound of the SM57 is what most people are used to hearing from a microphone, so it makes sense to measure the others against its performance.

Along the way he tests a huge number of microphones including famous and expensive ones from exclusive studios and finally one he made himself by mounting a cartridge atop a soda can. You’ll have to watch the video below the break for his conclusions, we can promise it’s worth it.

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One-String, One-Trick Pony Plays “the Lick”

October 4, 2023 by Kristina Panos 14 Comments

Wouldn’t you love to be able to play a song on a stringed instrument even though you don’t have an iota of musical talent? That’s the idea behind Strumli, a single-string instrument built by [Factorem] that plays “the lick”. You know, the lick. Chances are, you’ve heard it somewhere before.

Essentially, it’s a pill-shaped bowl with a soundboard. A high-E guitar string is wound around bearings and tuned with a guitar tuner. The lengths of string between the bearings correspond to each note in the lick. Strum it in the right direction, and Bob’s your uncle.

So how the heck did [Factorem] come up with the proper string lengths needed to play the song? After a bit of fancy math involving the equation that represents the relationship between the measurable frequency of a vibrating string under tension and the tension itself, [Factorem] had the overall length of the string. Then it was a matter of finding the frequencies needed to play the lick, along with their corresponding lengths.

Since the string exerts about 80 pounds of tension across the 3D-printed soundboard, some serious internal bracing is required, which [Factorem] figured out in CAD program. All the files are available if you want to build your own. Be sure to check out the build/demo after the break.

Would you rather just build a little harp? Here’s the inspiration for Strumli — a single-string number with a full octave.

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Cyanodore 6 Is A Rad Commodore 64 Synthesizer

September 29, 2023 by Lewin Day 3 Comments

The Commodore 64 is celebrated to this day for its capable SID sound chip, which provided the soundtrack for some of the best video games of its era. Even today, it’s still in demand as a chiptune synth. [gavinlyons] decided to take a breadbox-style C64 and mod it to be a more dedicated synth platform, creating what he calls the Cyanodore 6.

The build starts by equipping the C64 with MIDI via a C-LAB interface cartridge. Software is loaded on to the C64 via a readily-available SD2ISEC converter, which lets the retro computer run off SD cards. The original SID was removed and replaced with an ARMSID emulator instead, giving the rig stereo output with some custom wiring. Four potentiometers were also added to control various synth parameters by wiring them into the C64’s two joystick ports. There are a variety of synth programs that can run on the C64, with [gavinlyons] noting CynthCart, STATION64, and MicroRhythm as popular choices. Other nifty mods include the keyboard illumination, tube preamp, and integrated 7″ LCD screen.

If you’re looking to start using your C64 as a performance instrument, this build is an excellent starting point. We’ve seen other neat builds in this area before, too. It’s got just about everything you’ll need on stage. Video after the break.

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The Reverse Oscilloscope

September 25, 2023 by Al Williams 17 Comments

Usually, an oscilloscope lets you visualize what a signal looks like. [Mitxela]’s reverse oscilloscope lets you set what you want an audio waveform to look like, and it will produce it. You can see the box in the video below.

According to [Mitxela] part of the difficulty in building something like this is making the controls manageable for mere mortals. We really like the slider approach, which seems pretty obvious, but some other controls are a bit more subtle. For example, the interpolation control can create a squarish wave or a smooth waveform, or anything in between.

This is sort of an artistic take on an arbitrary waveform generator but with a discrete-panel user interface. The device contains a Teensy, a Raspberry PI Pico, a 16-bit ADC, and an external DAC. The Pico is little more than an I/O controller, reading the user interface and transmitting it on a serial port.

The outside construction looks excellent (we assume the tape is temporary). The inside is a bit messier, but still nicely done. There are many photos of the construction and details of problems along the way with 12-bit ADCs and power supply experiments.

Of course, if you don’t need the user interface, you can go crazy with waveform generation. We did our own similar project, but you could draw your waveforms on the PC instead of sliders.

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