Impressively Responsive Air Drums Built Using The Raspberry Pi Pico

January 2, 2024 by Lewin Day 6 Comments

Drum kits are excellent fun and a terrific way to learn a sense of rhythm. They’re also huge and unwieldy. In contrast, air drums can be altogether more compact, if lacking the same impact as the real thing. In any case, students [Ang], [Devin] and [Kaiyuan] decided to build a set of air drums themselves for their ECE 4760 microcontroller class at Cornell.

As per the current crop of ECE4760 projects, the build relies on the Raspberry Pi Pico microcontroller as the brains of the operation. The Pico is charged with reading the output of MPU6050 inertial measurement units mounted to a pair of drum sticks. The kick pedal itself simply uses a button instead.

Where the project gets really interesting, though, is in the sound synthesis. The build doesn’t simply play different pre-recorded samples for different drums. Instead, it uses the Karplus-Strong Drum Synthesis function combined with a wavetable to generate different sounds.

In the demo video, we get to hear the air drums in action, complete with a Stylophone playing melody. Unlike some toy versions that trigger seemingly at random with no rhythm, these air drums are remarkably responsive and sound great. They could be a great performance instrument if designed for the purpose.

We’ve seen similar builds before, too.

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Spooky Noise Box Plays War Drums

September 20, 2023 by Kristina Panos 6 Comments

What do you have cooked up to scare trick-or-treaters this Halloween? We humbly suggest adding in some type of noise box, especially one like this offering from [Paisley Computer] that uses reverb and other effects to achieve chilling, thrilling sounds.

As you can see, this instrument is essentially a bunch of doodads affixed to and through a cigar box. And as you’ll hear in the first video after the break, the various rubber bands make great drum sounds. The springs are nice, too, but our personal favorite has to be the head massager thing. Shhhing!

Inside the box you’ll find a guitar jack and some piezos glued to the underside of the top surface, but you’ll also find springs mounted across the inside that add to the resonance of the cigar box.

You can use either an interface and DAW or an effects pedal chain to really make things freaky, and [Paisley Computer] does a showdown between Focusrite interface versus various stomp pedals in the second video. In the third video, we learn how to make one of our own.

Do you like the idea of a spring reverb? How about a really big one that sounds sort of Satanic?

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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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Odd Inputs And Peculiar Peripherals: Miniature Steel Drums Become Rotary Mouse Controllers

June 29, 2022 by Robin Kearey 3 Comments

When [bornach] browsed through his office’s free-cycling box he found an old novelty toy that lets you play simple tunes on miniature steel drums. Such a thing is probably fun for about five minutes – if it’s working, which this one wasn’t. But instead of throwing it away, [bornach] spotted an opportunity in the capacitive touch pads on top of those little drums: they looked perfect to be modified into an unusual mouse cursor controller.

The operation started with [bornach] ripping out the original PCB and replacing it with an ESP32 D1 Mini. That board has a handy stack of touch-sensitive pins which could interface directly with the drums’ touch pads. He then programmed the ESP32 to interpret the signals as mouse movements and button presses, and send the results to a computer through a BlueTooth connection.

Operating the mouse drums is so straightforward that they almost appear made for this purpose: you slide your finger in circles along the touch pads to move the cursor in the X or Y direction, and touch the center pad to click. The left drum moves the cursor horizontally while the right one moves it vertically, but there’s also a mode to use the right drum as a scroll wheel.

The rotary X/Y controls are reminiscent of an Etch-a-Sketch; while probably too clumsy for everyday use, they might come in handy in some circumstances where you need to make single-pixel-accurate motions, if only to click those miniscule “close” buttons on some online ads.

Amazingly, this isn’t the first Etch-a-Sketch style mouse we’ve featured: this cute little wooden device works in a similar way.

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Arduino Drums Bring The Noise, No MIDI Required

June 2, 2020 by Tom Nardi 21 Comments

When looking through existing Arduino drum kit projects, [joekutz] noticed that most of them just used the microcontroller as an input for an existing MIDI device. That’s fine if you’re just looking to build your own hardware interface, but he wondered if it would be possible to forgo the MIDI device completely and actually generate the audio internally.

To be sure, this is a lot to ask of an 8-bit microcontroller, which is probably why nobody does it this way. But [joekutz] wasn’t giving up without a fight. One of the trickiest aspects was storing the samples: the 8-bit, 11.025 KHz mono WAV files ultimately had to be converted into C data arrays with a custom Python script.

Unfortunately, since the samples are essentially part of the drum’s source code, he says distributing the firmware is something of a problem. Though it sounds as though there might be a solution to this soon for those who want to play along at home.

But don’t get the impression that this project is just software. Check out the custom impact sensors lovingly crafted from popsicle sticks and metal cut from soda cans, which have been mated with sections cut out of old DVD-Rs. Actually getting the beats out of the Arduino required the addition of a R2R DAC circuit and a TDA2822 amplifier. In the video after the break, you can hear the results for yourself.

[joekutz] is no stranger to homebrew electronic instruments. When we last heard from him, he was turning a very pink keyboard into his own personal circuit bending playground.

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Homemade E-Drums Hit All The Right Notes

October 16, 2016 by Kristina Panos 8 Comments

In our eyes, there isn’t a much higher calling for Arduinos than using them to make musical instruments. [victorh88] has elevated them to rock star status with his homemade electronic drum kit.

The kit uses an Arduino Mega because of the number of inputs [victorh88] included. It’s not quite Neil Peart-level, but it does have a kick drum, a pair of rack toms, a floor tom, a snare, a crash, a ride, and a hi-hat. With the exception of the hi-hat, all the pieces in the kit use a piezo element to detect the hit and play the appropriate sample based on [Evan Kale]’s code, which was built to turn a Rock Band controller into a MIDI drum kit. The hi-hat uses an LDR embedded in a flip-flop to properly mimic the range of an actual acoustic hi-hat. This is a good idea that we have seen before.

[victorh88] made all the drums and pads out of MDF with four layers of pet screen sandwiched in between. In theory, this kit should be able to take anything he can throw at it, including YYZ. The crash and ride cymbals are MDF with a layer of EVA foam on top. This serves two purposes: it absorbs the shock from the sticks and mutes the sound of wood against wood. After that, it was just a matter of attaching everything to a standard e-drum frame using the existing interfaces. Watch [victorh88] beat a tattoo after the break.

If you hate Arduinos but are still reading for some reason, here’s a kit made with a Pi.

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RaspiDrums Uses Expensive Sensors

September 4, 2015 by Bryan Cockfield 3 Comments

Piezoelectric sensors are great for monitoring mechanical impacts with a microcontroller. Whether you’re monitoring knocks on a door or watching a heartbeat, they are a cheap way to get the job done. They do have their downsides, though, so when [Jeremy] wanted to build an electronic drum set, he decided to use more expensive accelerometers to measure the percussive impacts instead.

Even though piezo sensors are cheap, they require a lot of work to get them working properly. The ADXL377 3-axis accelerometer that [Jeremy] found requires much less work, plus provides more reliable data due to a 1kHz low-pass filter at the output. In his setup, a Raspberry Pi handles all of the heavy lifting. An ADC on each drum sends data about each impact of the drum, and the Raspberry Pi outputs sound via the native Alsa driver and a USB sound card.

This project goes a long way to show how much simpler a project like this is once you find the right hardware for the job. [Jeremy]’s new electronic drums are very well documented as well if you are curious about using accelerometers on your newest project rather than piezo sensors. And, if you’re into drums be sure to see how you can have drums anywhere, or how you can build your own logic drums.

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