Blog: entries tagged with "electronics"

The Bee and the Express

Express: back panel test mount I’m finally back to working on some electronic projects. First up, the Express, an analog-to-MIDI converter built around a Bare Bones Board, an inexpensive Arduino clone.

I’ve been making up some patches for my Evolver synth to use it as an effect on guitar or bass, and thought it’d be nice to have some sort of pedal to control it, along the lines of a wah or volume pedal. The desktop model of the Evolver lacks a pedal input, hence the Express (for “expression”, both of the musical and genetic kind - evolution, geddit?). Currently, it reads one analog pin and spits out continuous controller data. Nothing particularly spectacular there, but it did fit wonderfully into the sturdy steel case from a computer keyboard A/B switchbox. There’s room for lots more inputs, and eventually I figure it’ll sport an additional analog in and some footswitch inputs which will send things like note on/off messages.

I’m still new to making enclosures, and to working metal in particular - instead of grinding out a hole that was slightly too narrow, I used a drill, which grabbed hold of the edges and warped the heck out of the front panel. Panic set in for a moment, but I managed to bash the thing back into shape using a busted old hard drive(!) as an anvil.

Word to the wise: there are two incompatible standards for the wiring of expression pedals:

1/4” - tip to wiper / ring to +5V / sleeve to ground: Clavia, CME, Electrix, Emu, Kurzweil, Oberheim, Roland/Boss
1/4” - ring to wiper / tip to +5V / sleeve to ground: Kawai, Korg, Yamaha

The former arrangement allows you to use a standard normalling jack to connect the tip to ground by default, so the input doesn’t float if nothing’s plugged in. I’m using a Boss pedal now, but my other pedal is a Yamaha, so if I want to use it as a second input, I’ll have to wire up something to cross those connections.

Arduino (and Tarquin) Being easily distractible by possibilities - giant trackball! LED matrix! stepper motor-controlled time-lapse photography! - I’m desperately trying to focus on a couple of projects at a time. Arduino project number two at present is using it for ultra-cheap and dirty sound generation, with piezo disc speakers plugged directly into the digital outputs. A little hacked-together code, and voilà:

The Bee (MP3, 640k)

I call it the Bee, though “Mosquito” might have been more appropriate. Modulating the pulse width creates some nice motion, but there’s a lot more to do, like getting R/C filters to tame some of the harshness - it really is annoying after a while. Oh yes, and putting a switch on it to shut it up between tests. And, of course, buttons and knobs to play it with… maybe even some sort of acoustic treatment, like a resonating soundbox or a spring reverb.

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One of Stan Krzyzanowski's pine conesDorkbot Toronto, the local chapter of the network of “people doing strange things with electricity”, has a new slate of presentations, and last night was the first.

Patricia Rodriguez presented some of her video work using all sorts of cameras - film, video, digital - and taking advantage of each one’s unique features and most interesting ways of failing.

Cary Peppermint and Christine Nadir’s work is about breaking down the perceived borders between nature and the human-made world, using electronic media installations in unexpected places. Wild Information Network, a solar-powered streaming audio server installed deep in the woods of the Catskills, plays sound pieces submitted by various artists, all with the notion of humans broadcasting to the broader environment, or vice versa. It and other pieces are catalogued on their site:

Stan Krzyzanowski showed his time-lapse work, ranging from handheld still camera shots, to mesmerizing animations created from successive sections of wood and other materials (notably vegetables and marbled cheese), to his recent projects involving cones from various sorts of tree. Pine cones, see, open up as they dry and fold closed again if you get them wet. And when sped up, the waving of a big pine cone’s scales takes on an eerie, almost animal aspect.

It’s beautiful stuff. Interval is a rather huge archive of all his experiments - click some of the “special sets” on the lower right. Most of the best stuff is on the “Favorites” page.

The sessions are held at InterAccess, a gallery at Queen and Ossington devoted to electronic media art. They offer a very cool series of workshops on topics like microcontroller programming, introductory electronics, pinhole photography, and hacking your bike to turn it into a mobile piece of sound art. I’m hoping to attend the ones on Pure Data and creating “resilient outdoor works”.

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Many hands make light (art)work

Three pieces. The first two were passed along by a fellow DIYer who’s working on interactive electronic public art (thanks Gabe!):

GRL's Laser Tag system in operationFirst up, the Graffiti Research Lab and their collaborators have produced a laptop / camera / projector setup that lets you paint on the side of a building.

Their software lets you define the contours of the wall you’re projecting onto, then tracks the position of a laser pointer beam using video fed from the camera, and draws the resulting lines - with some simulated paint dripping, for added effect. Naturally, it’s open source, complete with instructions.

IMAGENext, Body Movies by Rafael Lozano-Hemmer. Portraits are projected on a huge scale on walls surrounding a public square, revealed in the shadows thrown by passers-by. If people in the square arrange themselves in a matching pose, the projections switch. But much more interesting is the ways that people spontaneously interact, given the possibility of casting gigantic shadows of radically different sizes. It turns into instant mimed improv.

Hello from Pika PikaAnd finally, PIKA PIKA, a “lightning doodle project”. Doodler Takeshi explains:

We took a photo of each image using long exposures and put them together to make them look like one animation.

To work on this project,we went out to various places in Japan:parks,under the train track,the Tokyo Bay,school hallways,and so on.

We got all sorts of friends in different fields together to work on this project.
During the process,they got to know each other and discover new things. This is also about “communication”.
People can meet new friends as they create a piece art very easy which brings every one happiness.
We spend a very enjoyable evening at the workshop and the party through this animation.

The results are delightful to watch, too - it’s like a live performance of a Norman McLaren scratch-animation film, with luminous creatures and designs running riot through real physical spaces. I love how the “performers” are often faintly visible, but obscured, like bunraku puppeteers.

The beauty of these projects is how intuitive they are to use. Casting shadows, drawing with light… even if they’re a little tricky to get the hang of, the concept is utterly simple and inviting. And they let people think and interact with their whole bodies.

Now we need to make “computers for the rest of you.” GUI technology allows you to drag and drop, but it won’t notice if you twist and shout.
— Dan O’Sullivan and Tom Igoe, Physical Computing

The body is the large brain.
— Brian Eno

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Arduino 7-segment output

I hit the electronics store the other day - sadly, they didn’t have any opto-isolators, so no MIDI input experiments this time round. But I scored some 74HC595 ICs, for the driving of LED displays and other digital outputs.

Here’s some code to run a common-cathode 7-segment display using the 595 (the Arduino site has a tutorial on how to hook up the 595, send data to it, and daisy-chain multiple ICs). I’ve included a list of which pins to connect to which anodes on the display in the character set file, below. Displays differ in their pinouts, so if you’ll likely need to do some testing to figure out how the pins are arranged.

charset_7seg.h - I spent a few minutes scribbling out a character set, and here it is as an #includeable file. (I put it in lib/targets/libraries/LED7Segment for the compiler to find.)

And here’s a test sketch. It lets you flip through the characters using a potentiometer on analog pin 0, but if you don’t have one handy you could easily adapt it to display the characters one by one.


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Two new toys

Desktop EvolverTwo new toys, and no time to play with them…

One is that Evolver I mentioned. It’s the desktop version, a monosynth with no keyboard. First impressions:

Sturdy metal case. Knobs are rotary encoders, i.e. the clicky digital kind, and are a little dodgy - maybe this will improve with time? Cleverly designed interface cuts down costs and space by packing dozens of parameters into a matrix so you can adjust them all using eight knobs: hit a button to select a row, then turn the corresponding knob. It takes a little getting used to, especially since half of the parameters also require you to hit the Shift button to get at them.

It can make pretty analogue sounds, and glittering digital sounds, and frightening noise. It has two audio inputs for use as a signal processor, and it can do some wonderful spacy things to a fretless bass. Here’s one minute of me goofing around, using it as a bass synth, a ghostly lead, a crunchy bit-hacked rhythm, and some other effects. A bit of echo, reverb and compression added in Logic.


Arduino USB boardThe other toy: an Arduino USB board.

Essentially, it’s a little computer processor on its own board. You can program it from a Mac, Windows or Linux box using a simple language based on C. It has a whole bunch of digital input/output lines, and six analog inputs that can double as pseudo-analog outputs (pulse-width modulated and not suitable for audio, but they work fine for dimming LEDs, for example). If you don’t need the USB interface, there’s a tinier, even cuter version.

More sounds and updates to come.

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theology cobra

Ahh, I needed that. New song-a-day track.

Bassline first: Fury thru POD, then software auto-filter; various loops processed to death; drums (Roland); FM pad; guitar thru POD; Alesis lead; rattling metal, treated, in place of a fill.

2007_0531_theology_cobra.mp3 (1′29)

I’ve been thinking: next time I get paid, it’s really time I got that Evolver I’ve had my eye on. But then I thought: wouldn’t it be more interesting to get a kit to build my own Paia 9700 system, for about the same amount of money?

Evolver: cute, tiny, patch editor allows “evolutionary” programming, can be used as a processor for external sound sources, doesn’t have to be assembled by hand

9700: insanely customizable, immediate and hands-on, has MIDI-to-CV outputs, can be used as a processor, external devices could be used to generate or modify control voltages

Something to think about.

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Greener computing

I’ve been pondering getting a big second monitor - in particular for the studio, where old CRT monitors create heaps of magnetic interference and AC buzz. But which manufacturers are the best, in terms of environmental impact? I’m talking cutting down on the hazardous chemicals, design for easy disassembly and recycling, take-back policies and so forth.

EPEAT A bit of web-searching turned up EPEAT, the United States EPA’s Electronic Product Environmental Assessment Tool. I note that no one in any of the categories yet meets EPEAT’s Gold standard.

Also, Greenpeace recently published their own Green Electronics Guide, and they’ve been pushing hard to get Apple to green its computers. (To me, they make sense as a target, since Mac devotees are something of a captive market, and may be a tad more likely to pay more for a greener computer.)

So the verdict? NEC’s MultiSync series and Apple’s Cinema Displays top EPEAT’s present list, but they’re ass-kickingly expensive for a monitor I’m not going to be using for high-end design. Dell’s more affordable, and as a company they’ve got one of the better environmental track records out there, so that’s how I’m leaning at present. Not that I’ll be dropping that much on anything for a while yet, but it’s good to know.

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Just like homemade

Neat project: Freqtric, a system that senses body contact and uses it to trigger MIDI drums (and presumably other instruments).

I don’t know if this is part of the device, or future plans for it, but I’d love to see a version that senses which two people have made contact - imagine a dance piece choreographed around a system like that! Ideally it’d be wireless, but that would kind of defeat the skin-resistance effect the Freqtric project uses. Maybe something using conductive gloves…

IMAGETaste of the Danforth was this weekend. Utter madness. One mile of Danforth closed while hundreds of thousands of people mill about lining up for cheap food and free samples. We caught a few minutes of music from a Cuban band, which caught my ear because I’ve been working on a new arrangement for “Catch-22”, our ostensibly Latin number. Sat up into the wee hours last night hammering out a bassline for it. It’s gonna groove.

Also, this week has been awesome for jamming. Found a very cool bunch of folks who are into free-form living room music-making. Very excited!

Also, my latest score from Active: DPDT switches, for the making of stomp boxes.

Also, I salvaged the caster “tree” from a dead swivel chair and a busted coat rack from the office, for the making of percussion stands.

I’ve rediscovered my true packrat nature. I’d been denying it for some years - partly I was paring things down, partly I was influenced by my SO’s firm belief in chucking things that don’t get used, partly it was because we move house every year or two. But now my packratting has purpose. I actually am building things with the junk I collect. Castoff things are an opportunity.

Building things from materials at hand - it’s a trait I inherited from my parents, and I think the whole attitude is one of their greatest gifts to me. Almost every piece of furniture we had was either a hand-me-down, bought used, or home-made. We just didn’t buy new things unless we really needed them.

  • For much of my childhood, our couch in the living room consisted of sleeping bags laid on top of foam on a bed of old wooden microscope boxes (which were all filled with old books, or tools, or five-pound chunks of rock with embedded fossils).
  • We had a little tractor/riding mower - that was bought new. But my dad built the trailer for it by sticking a box made of pegboard on top of an old lawn mower frame.
  • Mum sewed stuffed toys, including a whole basket of vegetables and a completely awesome dragon. Most of my toys were homemade too.

Of course, this filtered through to me - I’ve mentioned the surplus walkman before. On the music-making front, I made use of: kitchen utensils; cassette tape loops; weird instruments my parents had collected, like a psaltery, a manjolin, an ocarina; an early PC speech synthesizer fed through a disembowelled toy spring reverb; sound effects records spun slow, fast, and backwards; an electric guitar with its signal crammed through a Commodore monitor and my mum’s walkman speakers (I toasted them, along with many other devices); and a practice chanter for learning the bagpipes. These all showed up in the recordings of the Spastic Attack Dogs (a grand high school band name if ever there was one) - who reunited after university, learned to actually play, and became Flickershow.

After I moved out, I snagged an old wooden door from Mum and Dad’s place, propped it up on a pair of cabinets, and used it as a desk. It worked well except for the layers of peeling paint on it, which got worse due to me spilling water on it and frequently using it for drum practice. When my BF and I moved into our first apartment together in Toronto, I decided it was time to strip the paint off it. It turned out there was a layer of milk paint on it that wouldn’t budge, so we gave up, sanded the bugger to a splotchy, hideous, but smooth finish, and got new legs for it at Ikea. I still get ribbed about the “Eli and his *&#$ door” incident, but it’s big enough for two monitors, a synthesizer keyboard, a printer and a mixer, and I never see the surface of it anyway.

So of course I was delighted to discover ReadyMade, which is a magazine aimed square at people like me. Looks very cool - I even tried to subscribe, but their online subscription system broke in several ways and I got fed up. Will have to let them know.

So here’s my ongoing list of electronics projects, in rough order of difficulty:

  • An expression pedal (based around a fader rather than a rotary pot) - the electronics are bonehead simple; it’s the woodworking to make the rocker that’s the tricky bit. Starting with locating our hand saw.
  • A box with a simple photocell circuit for use an an expression-pedal input. Controlling something like the FilterQueen will require a more complex thing with a transistor or two, but I ain’t ready for that yet.
  • A ribbon controller. (All praise the late John Simonton.)
  • A simple fuzzbox circuit or two, snagged off the web (there’s loads of DIY stompbox circuits out there).
  • And way down the road: a “fretless” electronic instrument that feeds a signal from a piezo pickup through an analog-delay comb filter with the feedback turned way up, creating a ringing tone. The delay rate, and thus the pitch, is determined by a ribbon controller. I’m picturing two or three of these stacked together to resemble a very nerdy guitar. Left hand fingers notes on the ribbon-controller strings; right hand thumps and taps and scrapes a set of pads in which the piezo pickups are embedded. There’s another control for damping/feedback, but I don’t know how that’s handled yet. Lots of learning to go before I tackle that… but it’s one I’ve had in mind for a long while.

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Controller controller

It’s one of those nights. The only thing the cats are out prowling for is a spot with a decent breeze. Last night was the hottest night on record - 27 degrees.

So what the heck am I doing, sitting in the sweltering living room with a soldering iron?

potentiometerIt’s my first actually useful electronics project! (Well, unless you include the headphones I kept resurrecting back in high school - when the connector died, I put on a new one; when the cord itself died, I replaced it with a truly nerdy-looking one made out of black and red speaker wire, braided together. It went well with my walkman, which was ten dollars, as-is, at Active Surplus.)

Basically it’s proof-of-concept for some alternate controllers I’m thinking of making. The prototype: one 25k potentiometer soldered straight to one 1/4” tip-ring-sleeve plug. Tip goes to the wiper; ring and sleeve go to the fixed connections. (All parts came from Active Surplus - the day they close up shop is the last day I have any need to set foot on old Queen West.)

Plugged it into the volume pedal input on my Alesis keyboard, and tested it out in Cubase: worked the first time. The range is a bit broad - only about the middle 50% of the knob’s travel is useful, and it goes off the scale at either end.

But then came the test: plugging it into the expression pedal jack on my FilterQueen. And it worked like a charm. No range problems - just sweet, sweet, filter sweepin’ goodness. (Say, is the name FilterQueen a very roundabout “sweeping” -> “vacuuming” joke?)

For my next trick: two photocells wired back-to-back, also attached to a TRS plug. Tip goes to the junction between the photocells, ring and sleeve to opposite ends. My hope is that it’ll act as a resistor ladder with variable resistances on either side, and thus provide a slightly weird, wobbly and responsive controller. Onward!

Edit, 2:48am: YES. Works great on the Alesis. No go on the FilterQueen though - design tweaks are in order. But for now, I think it’s bedtime.

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Bass dreams

Lately a running theme in my dreams is ‘alternative ways of playing bass’. Like bowing it with the blade of an ice skate, a technique favoured by the devil in some sitcom. (I found myself on the show’s set between shows. The devil and the angel who shared the house along with an ordinary twenty-something guy, were hanging around, still in character.)

This morning I dreamt there were big lighted buttons of various shapes and colours all around the bridge of my bass like some sort of kid’s toy. Each button played a different tone. And I woke up going “Aww, you mean they’re not real?”

I once saw John Gzowski play guitar using some sort of little electronic noisemaker device which he placed over his pickups, sending the sounds direct to his amp. Maybe I should steal that idea.

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