Hearing live music is certainly enjoyable, but if the musician is using a drum machine, things can eventually get static. To add a bit more spontaneity into this class of robo-musician, Matt Bradshaw has created DrumKid — a handheld, battery-powered unit that uses random numbers to determine the rhythm and sound of a beat.

The device goes through a drum sequence, with a series of LEDs to indicate its progression, but also inserts randomly generated drum hits to the original beat. It features a variety of controllable parameters to alter how it sounds when played live via four knobs and six buttons.

The DrumKid was developed on an Arduino Uno and breadboard, then transferred to a PCB for the final version that will be for sale later this year. More info on the build is available in Bradshaw’s project write-up, while code and design files are on GitHub if you’d like to make your own!

When you need a distraction, or perhaps even now, you may turn to tapping on your desk. While a good way to keep your hands active, or pass a few uninteresting seconds, if you want to get serious with your finger drumming, then the “Arduino USB Drum” by creator colonelwatch may be just the thing.

The 3D-printable device hooks onto the edge of the table, and reads taps on its pads with a pair of strain gauges. Signals are amplified and passed along to an Arduino Uno—including tap intensity—which sends MIDI data to a computer via serial. 

Code and other build info are available on GitHub, and you can see a video of it in action here.

Drum machines may seem like one of the many rites of passage for hardware makers, they’re a concept you can implement simply or take into the extreme making it as complex as you want. [Matt’s] DrumKid is one of them, and its long development history is wonderfully documented in the project logs.

[Matt’s] original intention was to use the automatic drummer as part of his band, wanting “the expressiveness of a good drummer but without the robotic tendencies of a simple drum machine”. For that, he created the first iteration of the DrumKid, a web-based project using the Web Audio API. The interface consisted of bars showing levels for different settings which could be intuitively tweaked, changing the probability of a drum sound being played. This gave the “drummer” its unpredictability, setting itself apart from any regular old drum machine.

Fast forward a few years, and [Matt] now wants to recreate his DrumKid as a proper piece of musical gear, porting the concept into a standalone hardware drum machine you can plug into your mixer. He decided to go with the Arduino framework for his project rather than the Teensy platform in order to make it cheaper to build. The controls are simplified down to a few buttons and potentiometers, and the whole thing runs off of three AAA batteries. Also, targeting the project for hardware like this allowed for new features to be added, such as a bit-crush filter.

We already saw the first prototype here on Hackaday when it was featured in a Hackaday Prize mentor session, and it’s nice to see how the project evolved since. After a number of revisions, the new prototype takes design cues from Teenage Engineering’s “Pocket Operator” drum machine, using the main PCB as its own faceplate rather than a 3D printed case in a familiar way we’ve seen before. Unfortunately, the latest board is non-functional due to a routing mistake, but you can see the previous working prototypes in his project logs.

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There are a wide variety of ways to create electronic music. For a capable machine that fits in the palm of your hand and is loud enough to use outdoors, however, it’s hard to imagine a battery-powered device cooler than Bitty from Curious Sound Objects. 

The pocket-sized drum machine and synthesizer, currently on Kickstarter, was prototyped using an Arduino Nano and will be fully Arduino-compatible when released. This means that in addition to changing the sound and interface around with readily-available sound packs—which include Theremin Bitty, Techno Bitty, Basement Bitty, Trap Bitty, Lofi Bitty, and Beach Bitty—it can be programmed with the Arduino IDE. The device can even run sound software written for other Arduino boards.

Bitty features four sample trigger buttons, a pair of knobs, and a speaker. Designed for entry-level EDM enthusiasts and studio musicians alike, you can play the drums and melodies manually, as well as trigger patterns to produce dance music or hip hop beats. These can be chosen via the left knob, while the right knob handles pitch, note selection, and arpeggiation.

Check it out in action below!

The heart of the Atari 2600 wasn’t the 6502 (or the 6507 for the pedants), it was the TIA chip. This is the chip responsible for drawing graphics on the display, racing the beam, and extremely limited support for sound generation. We haven’t seen many attempts of using the Atari 2600 for chiptunes, but that doesn’t mean it can’t be done. [John Sutley]’s Syndrum, a take on an Atari 2600 drum machine is nearly a work of art. It’s a custom cartridge for the wood-paneled Atari, and an impressive input device that turns this classic console into a beat machine

Did the Atari 2600 ever come with a drum machine cartridge? Maybe. Probably not. [John] originally built this project to experiment with the TIA chip, but found it was less tonal than a kazoo. That struck ‘Atari synthesizer’ off the list and replaced it with an ‘Atari drum machine’. There are two key parts of the build here, the first being a repurposed Asteroids cartridge that had the PROM replaced with a ZIF socket. This allows [John] to easily burn new code to an EEPROM, stuff it in the socket, and run it on the Atari. All the code was developed with batari Basic, a BASIC-inspired language that spits out .bin files for the Atari.

But running code on the Atari is just one half of this build. To do a drum machine, you somehow need to tell the Atari when to play each sound. Given the lack of expansion capabilities for the Atari, [John] turned to the controller port. The Syndrum uses Arduino Nano to bridge the DE9 controller connector to a MIDI port. Yes, it’s real MIDI, on a machine that could probably never do MIDI natively (although we’d love to see someone try).

Need a video of this mind-blowing hack in action? Here you go:

Circuit bending doesn’t get a lot of respect around some parts of the Internet we frequent, but there is certainly an artistry to it. Case in point is the most incredible circuit bending we’ve ever seen. Yes, it’s soldering wires to seemingly random points on a PCB, but these bend points are digitally controlled, allowing a drum machine to transform between bent crunchiness and a classic 1980s drum machine with just a few presses of a touch screen controller.

All circuit bending must begin with an interesting piece of equipment and for this project, [Charles], the creator of this masterpiece of circuit bending, is using a Roland TR-626, a slightly more modern version of the TR-606, the percussive counterpart of the infamous TB-303. The circuit is bent in the classical fashion – tying signals on the PCB to ground, VCC, or other signals on the board. [Charles] then out does everyone else by connecting these wires to 384 analog switches controlled by an Arduino Mega. Also on the Arduino is a touch screen, and with a slick UI, this old drum machine can be bent digitally, no vast array of toggle switches required.

[Charles] has put up a few videos going over the construction, capabilities, and sound of this touch screen, circuit bent drum machine. It’s an amazing piece of work, and something that raises the bar for every circuit bending mod from this point on.

Thanks [oxygen_addiction] and [Kroaton] for sending this one in.

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Read the full article on MAKE