Pi Pico Lays Down The Groove

October 30, 2024 by Bryan Cockfield 7 Comments

From the 60s to perhaps the mid-00s, the path to musical stardom was essentially straight with very few forks. As a teenager you’d round up a drummer and a few guitar players and start jamming out of a garage, hoping to build to bigger and bigger venues. Few people made it for plenty of reasons, not least of which was because putting together a band like this is expensive. It wasn’t until capable electronic devices became mainstream and accepted in popular culture in the last decade or two that a few different paths for success finally opened up, and this groovebox shows just how much music can be created this way with a few straightforward electronic tools.

The groovebox is based on a Raspberry Pi Pico 2 and includes enough storage for 16 tracks with a sequencer for each track, along with a set of 16 scenes. Audio plays through PCM5102A DAC module, with a 160×128 TFT display and a touch-sensitive pad for user inputs. It’s not just a device for looping stored audio, though. There’s also a drum machine built in which can record and loop beats with varying sounds and pitches, as well as a sample slicer and a pattern generator and also as the ability to copy and paste clips.

There are a few limitations to using a device this small though. Because of memory size it outputs a 22 kHz mono signal, and its on-board storage is not particularly large either, but it does have an SD card slot for expansion. But it’s hard to beat the bang-for-the-buck qualities of a device like this, regardless, not to mention the portability. Especially when compared with the cost of multiple guitars, a drum set and a bunch of other analog equipment, it’s easy to see how musicians wielding these instruments have risen in popularity recently. This 12-button MIDI instrument could expand one’s digital musical capabilities even further.

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A Parts Bin MIDI Controller In 24 Hours

October 20, 2024 by Bryan Cockfield 9 Comments

Part of the reason MIDI has hung on as a standard in the musical world for so long is that it is incredibly versatile. Sure, standard instruments like pianos and drums can be interfaced with a computer fairly easily using this standard, but essentially anything can be converted to a MIDI instrument with the right wiring and a little bit of coding. [Jeremy] needed to build a MIDI controller in a single day, and with just a few off-the-shelf parts he was able to piece together a musical instrument from his parts bin.

The build is housed in an off-brand protective case from a favorite American discount tool store, but the more unique part of the project is the choice to use arcade buttons as the instrument’s inputs. [Jeremy] tied eight of these buttons to an Arduino Uno to provide a full octave’s worth of notes, and before you jump to the comments to explain that there are 12 notes in an octave, he also added a button to the side of the case to bend any note when pressed simultaneously. An emergency stop button serves as a master on/off switch and a MIDI dongle on the other side serves as the interface point to a computer.

After a slight bit of debugging, the interface is up and running within [Jeremy]’s required 24-hour window. He’s eventually planning to use it to control a custom MIDI-enabled drum kit, but for now it was fun to play around with it in some other ways. He’s also posted the project code on a GitHub page. And, if this looks a bit familiar, this was not [Jeremy]’s first MIDI project. He was also the creator of one of the smallest MIDI interfaces we’ve ever seen.

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Beat Backing Box For Bassists

December 23, 2022 by Bryan Cockfield 9 Comments

The soul of a rock band is its rhythm section, usually consisting of a drummer and bass player. If you don’t believe that, try listening to a band where these two can’t keep proper time. Bands can often get away with sloppy guitars and vocals (this is how punk became a genre), but without that foundation you’ll be hard pressed to score any gigs at all. Unfortunately drums are bulky and expensive, and good drummers hard to find, so if you’re an aspiring bassist looking to practice laying down a solid groove on your own check out this drum machine designed by [Duncan McIntyre].

The drum machine is designed to be as user-friendly as possible for someone who is actively playing another instrument, which means all tactile inputs and no touch screens. Several rows of buttons across the top select the drum sounds for the sequencer and each column corresponds to the various beats, allowing custom patterns to be selected and changed rapidly. There are several other controls for volume and tempo, and since it’s based on MIDI using the VS1053 chip and uses an STM32 microcontroller it’s easily configurable and can be quickly interfaced with other machines as well.

For anyone who wants to build their own, all of the circuit schematics and code are available on GitHub. If you have an aversion to digital equipment, though, take a look at this drum machine that produces its rhythms using circuits that are completely analog.

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Lego Plays Electronic Drums

October 22, 2022 by Danie Conradie 15 Comments

The ability to quickly try out an idea, and then expand and develop it, is what rapid prototyping is all about. Although we tend to think of 3D printing when rapid prototyping is mentioned, [Brick Technology] reminds us of the power of Lego, as he rapidly builds and improves an electromechanical drum machine.

Using Lego Technic pieces, he starts with a simple music box-style drum with moveable pins that pluck on spring-loaded levers, which in turn hit piezoelectric discs. The electronics side is simple, with the discs wired to a Roland sound module from an existing electronic drum kit. With the ability to instantly adjust, add and remove pieces, he quickly finds and fixes the problem of getting eleven hammer mechanisms together and working smoothly.

To get around the limited pin space on the drum and increase the length and variation potential of the rhythms, [Brick Technology] moved to a belt design that can accommodate significantly more pins. He also added an electric motor and various gearbox ratios for consistent and adjustable tempo. Together with his water vortex ball machine, he makes us think our workshops probably need a few hundred Lego Technic pieces.

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How The Roland 808 Cowbell Worked

May 12, 2022 by Jenny List 9 Comments

Every generation has an instrument which defines its sound, and for those whose formative musical years lie in the 1980s, a very strong contender to the crown is the Roland TR-808 percussion synthesizer. Its sounds can be recognized across a slew of hits from that era and every decade since, and though the original instrument wasn’t a commercial success it remains accessible through sample packs, emulations, and clones. The 808 was an all-analogue device that didn’t use samples, thus [Mark Longstaff-Tyrrell] has been able to reproduce its distinctive cowbell sound with reference to some of the original circuitry.

It shouldn’t come as too much of a surprise to find that the circuit is refreshingly simple. The trigger pulse is converted into an envelope which controls a pair of oscillators. The mixed output passes through a bandpass filter to create the distinctive sound on the output which you can hear in the video below the break. The circuit is recreated on a breadboard with the only concession to modernity being a microcontroller taking the place of the Schmitt trigger oscillators in the original.

Altogether it provides a fascinating insight into the synthesis behind a classic sound, and gives us an increased appreciation for the design skills of those Roland engineers who created it. We’ve looked at the 808 before a few times, including an explanation of the famous faulty transistors which contributed to its sound.

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Antique Beat Box Showcases 1950’s Engineering Prowess

March 3, 2022 by Ryan Flowers 35 Comments

Before you could just put a drum machine app on your phone, or fire up Garage Band, there were breakthroughs like the Roland 808 drum machine. But that’s not where it all started. In 1959 a company called Wurlitzer (known for things like juke boxes, pianos, and giant pipe organs) produced a new device that had musicians worried it would put drummers out of a job: The 1959 Wurlitzer Sideman. And in the video below the break, we have the joy of watching [LOOK MUM NO COMPUTER] open up, explain, and play one of these marvelous machines.

Can you spot the early circuit sculpture?

It’s noteworthy that in 1959, almost none of the advancements we take for granted had made it out of the laboratory. Transistors? Nope. Integrated Circuits? Definitely not. What does that leave us with? Vacuum tubes (Valves for those across the pond), resistors, capacitors, relays, and… motors? Yep. Motors.

The unit is artfully constructed, and we mean that quite literally- the build was clearly done with care and it is easy to see an early example of circuit sculpture around the 3 minute mark. Electromechanical mechanisms take on tasks that we’d probably use a 555 for these days, but for any of you working on mechanical projects, take note: Wurlitzer really knew what they were doing, and there are some excellent examples of mechanical and electrical engineering throughout this primordial beat box.

If you move to the beat of interesting drum machines, you might enjoy this Teensy based Open Source drum machine that you can build. No tubes required!

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Electronic Drum Toy Built From Scratch

January 11, 2022 by Lewin Day 9 Comments

Drum kits used to be key to any serious band, however, these days, much of our music is created on computer or using a drum machine instead. [spanceac] has built a simple example of the latter, using a microcontroller to build a basic sample-based drum toy.

The brains of the operation is the STM32F100VET6B, which comes complete with a 12-bit DAC for outputting sound. It’s also got a healthy 512 KB of flash, enabling it to store the drum samples onboard without the need for extra parts. Samples are stored at a sample rate of 22,050 Hz in 16-bit resolution – decent quality for a tiny little build, even if the DAC chops that back down to 12-bits later.

[spanceac] was sure to code proper mixing into the drum machine, so that triggering a second sample doesn’t stop the first one playing. With a kick, snare, two toms, and crash and ride samples onboard, there’s plenty to get a solid beat going on the kit. It’s all built up on a small PCB with tactile buttons to activate each sound.

The demo video shows the kit performing ably; it’s not clear if there’s an issue with latency on the samples or that’s just from the difficulty of [spanceac] playing one-handed. If the former, likely some code tweaks or simply trimming silence at the start of samples would be all that was needed. Overall, it’s a neat little groovebox, and the kind of thing that’s great fun to use when jamming with other musicians. Video after the break.

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