BBC Micro:Bit As Handheld Synthesizer

December 17, 2022 by Bryan Cockfield 4 Comments

The BBC Micro:bit, while not quite as popular in our community as other microcontroller development boards, has a few quirks that can make it a much more interesting piece of hardware to build a project around than an Arduino. [Turi] took note of these unique features and decided that it was the perfect platform to build a synthesizer on.

The Micro:bit includes two important elements that make this project work: the LED matrix and a gyro sensor. [Turi] built a 5×5 button matrix for inputs and paired each to one of the diodes, which eliminates the problem of false inputs. The gyro sensor is used for detuning, which varies the pitch of any generated sound by a set amount according to the orientation of the device. It also includes a passive low-pass filter to make the sound more pleasant to the ear, especially for younger players of the machine. He’s released the source code on his GitHub page for anyone interested in recreating it.

While this was a one-off project for [Turi], he notes that using MicroPython to program it instead of C led to a lot of unnecessary complications, and the greater control allowed by C would enable some extra features with less hassle. Still, it’s a fun project that really showcases the unique features of this board, much like this tiny Sumo robot we covered over the summer.

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DIY Square Guitar Is Anything But

December 17, 2022 by Kristina Panos 3 Comments

One of the greatest things about this place is how y’all constantly feed off of each other. And while this isn’t exactly an example of that, it’s pretty darn close — we feature a square guitar build one day, and get a tip about another way different and perhaps more functional one the next.

[Craig Lindley] had no idea of his luthier powers until an email from StewMac inspired him to build his own guitar. Rather than strip a perfectly good axe or two for all the parts, he bought the hardware and a pre-made neck, and built the body himself. The Bo Diddley-inspired boxy body is an ice cream sandwich of sapele, inlaid with white ash around the perimeter which is quite the classy look. Speaking of looks, [Craig] worried that all-gold hardware would be too flashy, but we think it looks great.

Not hard-mode enough for you? Well, here’s a guitar made from scratch, (more or less). If you’d rather have more of a teaching guitar, behold this LED-laden axe.

Kids’ Jukebox Based On Arduino With RFID

December 16, 2022 by Bryan Cockfield 10 Comments

Consumer electronics aimed at young children tend to be quite janky and cheap-looking, and they often have to be to survive the extreme stress-testing normal use in this situation. You could buy a higher quality item intended for normal use, but this carries the risk of burning a hole in the pockets of the parents. To thread the needle on this dilemma for a child’s audiobook player, [Turi] built the Grimmboy for a relative of his.

Taking its name from the Brothers Grimm, the player is able of playing a number of children’s stories and fables in multiple languages, with each physically represented by a small cassette tape likeness with an RFID tag hidden in each one. A tape can be selected and placed in the player, and the Arduino at the center of it will recognize the tag and play the corresponding MP3 file stored locally on an SD card. There are simple controls and all the circuitry to support its lithium battery as well. All of the source code that [Turi] used to build this is available on the project’s GitHub page.

This was also featured at the Arudino blog as well, and we actually featured a similar project a while ago with a slightly different spin. Both are based on ideas from Tonuino, an open source project aimed at turning Arduinos into MP3 players. If you’re looking to build something with a few more features, though, take a look at this custom build based on the RP2040 microcontroller instead.

closeup of an electric ukulele conversion of a toy guitar, showing the four strings and the pickups mounted inside the sound hole

A Kid’s Toy Guitar Turned Into An Electric Ukulele

December 15, 2022 by Dave Walker 8 Comments

With the holiday season fast approaching, there’s a good chance that some well-meaning friend or relative might buy a toy musical instrument for your children, safe in the knowledge that they’ll never have to listen to the results! The sound from these cheap toy guitars is pretty terrible, partly because they’re just too small to tune to a pleasing guitar tuning, so [joekutz] decided to see if one could be turned into an electric ukulele instead.

The first modification on the list was to reduce the string count from six to four, by notching out new positions on the nut and drilling the corresponding fixings on the bridge. One advantage of these cheap instruments is that it’s less of a risk to take tools to the bodywork!
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Nanoaetherphone Is A Special MIDI Controller

December 14, 2022 by Lewin Day 11 Comments

MIDI controllers can be simple straightforward keyboards, or wild magical devices that seem to snatch notes from the very aether itself. As you might expect from the name, the Nanoaetherphone II is one of the latter.

The device is inspired by the Theremin, and was built to celebrate its 100th anniversary. The Nanoaetherphone II is all about using sensors to capture data from wireless hand-wavey interactions, and turn it into MIDI messages. To this end, it has an LDR sensor for detecting light levels, which determines volume levels. This is actuated by the user’s thumb, blocking the sensor or allowing ambient light to reach it. At the front of the handheld unit, there is also an ultrasonic range sensor. Depending on how close the sensor is to the user’s hand or other object determines the exact note sent by the device. As a MIDI controller, it is intended to be hooked up to an external synthesizer to actually generate sound.

The overall concept isn’t too complicated, and the design makes it easy to pickup and play. We imagine it could even be foolproofed by programming it only to play notes from a given scale or mode, allowing for easy soloing without too many of those ill-tempered blue notes. Jazz enthusiasts might prefer it to just spit out any and all notes, of course.

We love a good MIDI controller around these parts, and we’ve seen everything from knitted models to those made out of old phones. Video after the break.

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A walnut ukulele with an aluminum piece routing strings at it's base which is facing the camera. The neck of the instrument extends away from the viewer and is held at an angle by a hand with striped sheets in the background.

Travel Uke From A Fallen Tree

December 12, 2022 by Navarre Bartz 6 Comments

When faced with what to build from the trimmings of the walnut tree in her yard, [Amy Qian] decided to build a headless travel ukulele. [via MAKE:]

Headless instruments relocate the tuners to the body of the instrument, and [Qian] had to do a fair bit of trimming and whittling on the body to make the tuners fit just right and still be operable via four scoops cut into the sides. After some initial troubles with the amount of friction on the strings produced by the mandrel, she replaced it with a set of ball bearings and a holder she machined out of aluminum.

We love how [Qian]’s extensive build log goes through the entire process of making this diminutive instrument from trimming dead walnut branches to building a playable instrument. Little details like the maple strip in the neck and the cocobolo accents really take this far beyond the cigar box instruments that start many down the path of luthiery.

Looking for more musical hacks? How about this set of Commodore 64s turned into an accordion or this Baguette Theremin?

PDP-8 Plays Period Popcorn Piece

December 11, 2022 by Chris Lott 18 Comments

[Kyle Owen], collector of antique tech, decided to try his hand at music arrangement — for the PDP-8 computer, that is (listen to the video below the break). He’s using a program submitted by Richard Wilson to the Digital Equipment Corporation Users Society (DECUS) in 1976, appropriately named MUSIC. It runs on OS/8 and is written in the PDP-8 assembly language PAL8. Using the syntax of MUSIC, [Kyle] arranged Gershon Kingsley’s famous Moog synthesizer hit “Popcorn” (the Hot Butter version from 1972).

You might notice the lack of a disk or tape drive in his setup. That’s because [Kyle] is using an RK05 disk emulator he wrote back in 2014. It’s running on a Raspberry Pi and connects over serial, which he says is slower than an RK05 but faster than a tape drive. He has connected up a Cordovox amplifier cabinet for this demonstration, but the original means of listening to the MUSIC output was an AM radio held near the computer (hear the second video below the break). This worked by executing the PDP-8 CAF instruction at a desired frequency, say 440 Hz.

Thus, when this instruction is executed, logic all over the computer goes “zap”, clearing out various registers. Now, if a radio is held close to the computer, it will pick up some of this energy, and at 440 times a second, will deliver a pulse to the speaker. The result is that you will hear a tone from the radio — as a matter of fact, you will hear an A.

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