Logic Noise: Filters And Drums

March 25, 2015 by 17 Comments

Filters and Drums

Logic Noise is an exploration of building raw synthesizers with CMOS logic chips. This session, we continue to abuse the 4069UB as an amplifier. We’ll turn the simple unity-gain buffer of last session into a single-pole active lowpass filter with a single part. (Spoiler: it’s a capacitor.)

While totally useful, this simple filter is a bit boring and difficult to make dynamic. So we’ll look into an entirely different filter, the Twin-T notch filter, that turns out to be sharp enough to build a sine-wave oscillator on, and tweakable enough that we’ll make a damped-oscillator drum sound out of it.

Here’s a quick demo of where we’re heading. Read on to see how we get there.

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Drums Anywhere!

January 16, 2015 by 16 Comments

The students over at Cornell’s School of Electrical and Computer Engineering have been hard at it again with their senior projects. This time, it’s the very tiny and portable drumset dubbed Drums Anywhere by its creators [Shiva Rajagopal] and [Richard Quan]. Since there are other highly portable instruments like roll-up pianos, they suppose there should be a portable drum kit that actually sounds like drums, and this ECE duo have hit the metaphorical and physical drum on the head… except that this project doesn’t actually use physical drums to make sound.

The project consists of two 3D-printed box-like sensors with velcro straps that can be attached to any drumstick-shaped object that might be lying around. Inside the box is a flex sensor and a tiny microphone which report the “beats” to a microcontroller when they strike another object.

On the software side, there are two sampled sounds stored in the microcontroller but they plan to add more sounds in the future. The microcontroller outputs sound to a pair of speakers, and the sensors are sensitive to force, so the volume can range from almost inaudible all the way up to [John Bonham]-style booms. This could also be theoretically expanded to include more than two “beat boxes” for extra sounds, or be wireless. The options are virtually limitless, although the team notes that they are limited by the number of interrupts and ADC converters on their particular microcontroller, an ATmega1284.

This is another interesting take on a having drumset without the drums, and definitely expands the range of what a virtual drum set can do. It’s also great to see interesting projects coming from senior design classes! Be sure to check out the video after the break.

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Sound Reactive Drums Of Trailing Light

January 4, 2015 by 8 Comments

If you’re going to be the drummer in a band for a Back to the Future themed New Years Eve party, you really need to add something to your gig that captures that kitschy futuristic ambiance as seen by the 80s. Rainbow LEDs will do the trick.

For his drum set’s reactive trailing light display, [Alec Smecher] was inspired by a similar project he’d seen in the past where Neopixels were added to a regular drum kit and activated with several individual microphones. Since the microphones ultimately heard all of the thundering noise from every drum and cymbal at once, there was a lot of bleed over in the response of the LEDs. To remedy this, [Alec] used piezo pickups which listen to discrete surface vibrations rather than sound in order to clean up the effect produced by the lights. Each of the five LED strips lining the stands of his cymbal and inside of his drums were programmed to react with a burst of light equal in brightness to the intensity of the vibration sensed by the piezo.

To insure everything kept together amidst all the constant motion and shaking during performance, [Alec] soldered his connections directly onto his Trinket’s pins as well as the fragile pickup of the piezo. The pickup of the sensors were taped directly against the skin of his drums and along the inside of each cymbal to maximize responsiveness. After ringing in the new year appropriately as the ‘band from the future’, [Alec] reports that his colorful addition worked fantastic the whole night.

Those interested in building their own can find a nice schematic on [Alec’s] blog as well as the code he used on github. Difficulty level taken into account, this is a great first project for a musician who has yet to dabble in electronics… and seeing that it’s a brand new year, there’s no better time to have a go at something new.

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Gemma-Powered NeoPixel Sound Reactive Drums

August 26, 2014 by 8 Comments

adafruit_products_drum-slide-out

This tutorial from Adafruit shows how to create a custom interactive drum set that lights up with sound. It uses a mic amp sensor that is connected to a miniature Arduino Gemma board to detect when the instrument is being hit by the sticks. Neopixels then illuminate into a range of colors creating a beautifully synced up music presentation.

The container that houses the electronics is 3D printed. The entire circuit is integrated into the snare, mid-tom, hi-tom and a drum kick. All the code and step-by-step instructions can be found on Adafruit’s website. Now imagine something like this being packed up in a suitcase and carried from venue to venue as an up-and-coming band travels from state to state on tour; especially at Drum n’ Bass raves or electronic based music festivals. A video of the kit being used is below.

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Make A Wind Turbine From 55 Gallon Drums

February 9, 2012 by 34 Comments

vertical axis wind turbine

Although there are several vertical axis wind turbines listed on greenterrafirma’s page, the one built with 55 gallon drums was especially interesting to us.  Although the spouse approval factor of any of these designs is debatable, at $100, the 55 gallon drum design could provide a very good return on investment.  The tools required to make one of these are relatively simple, so this could make this experiment accessible to those without a vast arsenal of equipment.

If large blue barrels aren’t your thing, the post also features several other turbine designs, including one made with wood and aluminium foil, and one constructed out of PVC pipe.  The video after the break does a good job of explaining the “blue barrel” construction process, but if you’d rather just see this [VAWT] in action, fast forward to 5:25.

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Hydroponic Strawberries Sweeten Up Winter Dolldrums

February 8, 2012 by 31 Comments

Add some fruit to your indoor bounty with this hydroponic strawberry farm. [Dino] whipped this up as his 45th hack a week episode (getting pretty close to his year-long goal). He used parts you probably already have sitting around the house somewhere. But even if you bought everything and used it once you still wouldn’t be out much.

A plastic storage container serves as the base. [Dino] also grabbed four identical plastic containers (large yogurt containers would work here) to host the plants. He cut off the bottom half and inserted some netting to keep the plant from falling through. After tracing the size of the container on the enclosure’s lid he cut out holes which will host each plant. This provides a way to dangle the roots into the nutrient solution which is kept oxygen rich with an aquarium pump and two air stones. It certainly deserves a place next to that salad farm you threw together. Don’t miss [Dino’s] build video after the break.

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MIDI Air Drums Let You Play Anywhere

July 29, 2011 by 26 Comments

[Maayan Migdal] wrote in to share a really cool drum kit he constructed that has one special twist – no drums at all. Using a simple MIDI device and an Arduino, his “Air Drums” look pretty sweet.

The hack makes use of a pair of garden rakes, which serve as his drum sticks. The rakes were cut down and modified to allow the addition of accelerometers and some USB cables. The left stick contains a single accelerometer for registering hi-hat hits, while the right stick is armed with a pair of the modules, which are used to trigger snare and crash symbol strikes. He modified a pair of sandals to fit better while drumming before adding a sensor to each shoe. The left sandal contains an accelerometer to register bass drum hits, while the right shoe uses a light sensor to simulate the use of a hi-hat pedal.

We think that the results are awesome, but feel free to check out the video below to see what we mean. If Guitar Hero wasn’t dead in the water on hiatus, we think this sort of setup would make a great replacement for the flimsy drum set that comes with the game.

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