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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Drumming A Beat On A Hundred-Year-Old Typewriter

May 7, 2020 by Moritz v. Sivers 8 Comments

We have seen a fair share of unusual items being turned into musical instruments. Luckily, with a little bit of hacking it is possible to turn almost anything into a MIDI controller. [William Sun Petrus] just converted a 1920s typewriter into a drum machine and delivers a hell of a live performance on it.

The build is rather simple, all [William Sun Petrus] needed was an Arduino Mega and lots of wires to convert a hundred-year-old Remington typewriter into a MIDI controller. Whenever a key is pressed the hammer hits a metal plate at the center of the typewriter and closes the contact between one of the Arduino’s IO pins and the 5 V rail like a regular push button. The Arduino code is based on the MIDI library sending commands to a PC which is running Hairless MIDI and Ableton. As sort of a gimmick, [William Sun Petrus] included an LCD screen which shows a line from Green Eggs and Ham by Dr. Seuss every time a key is pressed.

Interestingly, the latency due to the hammer’s travel time does not disturb [William Sun Petrus’] live play. To calm the skeptics in the comments he also released an unedited version of the video to prove that the performance is real and an instructional video on how to play his beat note by note.

Other unusual MIDI controllers include a bandoneon accordion or this English concertina.

Video after the break.

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Shapeshifter – An Open Source Drum Machine

October 13, 2019 by Lewin Day 2 Comments

With microcontrollers growing ever more powerful each new generation, things that were mere pipedreams before are now readily possible. The Shapeshifter drum machine is a perfect example.

Shapeshifter’s design is open-source, with everything available on Github for the curious musical tinkerers out there. The device is built around a PCB with only through-hole components, making assembly easy for even the least experienced enthusiasts out there. A Teensy 3.6 is then slotted into the socket on the board, providing 180MHz of grunt to run the show. It’s an excellent choice, as the Teensy platform has a huge range of libraries which make it simple to work with audio.

Being open-source, not only is it a cinch to make your own, but there’s plenty of room to remix the design to your personal tastes. There’s even a breadboarding area and the capability to add an expansion card for even more possibilities. Some users have even gone so far as to add displays and filter mods to really open things up.

We love a good drum machine at Hackaday, from the Amstrad-based to pocket-sized wonders. If you’ve got a build of your own, be sure to drop it in the tips line.