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Design visualization lab workshop series session #4. Michael Una. Circuit Bending and simple human interface. We will attempt to modify existing electronic circuits to accept new and unintended human interface controls.
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Design visualization lab workshop series session #4 Michael Una
Circuit Bending and simple human interface • We will attempt to modify existing electronic circuits to accept new and unintended human interface controls. • We will build a simple circuit from the ground up and explore various means of influencing the output.
Reed Ghazala’s Art of Circuit Bending “Circuit-bending is an electronic art which implements creative audio short-circuiting. This renegade path of electrons represents a catalytic force capable of exploding new experimental musical forms forward at a velocity previously unknown. Anyone at all can do it; no prior knowledge of electronics is needed. The technique is, without a doubt, the easiest electronic audio design process in existence. “ http://www.anti-theory.com/soundart/circuitbend/
Reed Ghazala’s Art of Circuit Bending Reed Ghazala’s Art of Circuit Bending “Within these adapted devices, along with the unusual voices of circuit-bending, are often found aleatoric music generators; that is, chance-music composers that stream unpredictable audio events: elements shifting and re-combining in fascinating ways. Body-contacts are also found through circuit-bending. These allow electricity to flow through the player's body, flesh and blood now becoming an active part of the electronic sound circuit. This interface extends players and instruments into each other, creating, in essence, new life forms. An emerging tribe of bio-electronic Audio Sapiens.” http://www.anti-theory.com/soundart/circuitbend/
What makes a device bendable? Two words: cheap construction. Most toy musical instruments are made very cheaply and operate on somewhat simple principles of synthesis/sampling. So what are the telltale signs of a bendable device? • Does it make a neat/terrible sound? Keep in mind- this object makes sounds, which you are going hear a whole lot as you modify. It helps if you enjoy the sounds to begin with, or conversely that you absolutely hate them and want to change them completely. 2. Look at the size of the case- once you open it up, will there be enough room inside to kludge around and put more things in? Most toys do, but any micro- or keychain-sized devices do not.
What makes a device bendable? 3. Play around with it, if possible before buying. Keep some AAA and AA batteries in your pocket, and a small screwdriver in case the battery compartment is bolted on. There’s nothing worse than taking a potentially fun device home and discovering that it’s completely dead. 4. Does it have a funny or awesome name? Chances are, yes. Who comes up with these names stamped in plastic, I do not know. But often, they are weird and hilarious.
LEGal One word to the wise- WARNING: UNLESS YOU ABSOLUTELY KNOW WHAT YOU’RE DOING, ONLY BEND DEVICES THAT OPERATE ON BATTERIES! I’m serious.
What kind of bends can you expect? There are generally two kinds of toy instruments out there: • Synthesizing devices, which generate sound through actual (cheap) oscillators, filters, etc. Some cheap keyboards work this way,and I’ve found a few electronic drum kits that do. Speak and Spells fall in this category also. These can be bent in numerous ways to distort, short circuit, and self-oscillate. What does this translate to sonically? Anything from squidgy bleeps, to analog synth-sounding waveforms, to escalating (siren-like) tones to white noise. These are the easiest to bend, because pretty much all the circuitry is dedicated to audio generation.
What kind of bends can you expect? 2. Sampling/sampled devices, which play back a pre-recorded sound from a memory chip. These can be a little more complex, or less inviting to the casual bender. Sampling devices can be modified by changing the sample rate of the chip (often with a variable resistor) for wild pitch bends and glitchy, digital blurps, or by shorting out the chip and triggering “partials” of the recorded sound. Sometimes, a contact point can be found that causes the sounds to loop indefinitely.
How to go about finding a bend point First, get out your screwdriver and remove the back of the device’s housing. At this point, you have several options. Trigger a sound, then: 1. Lick two fingers and touch them to various points on the circuit board. 2. Use your screwdriver to bridge two points 3. Use a wire that’s been stripped at both ends to bridge two points 4. if you want to be more analytical, use a bit of wire with alligator clips at both ends. Anchor it to one point, then touch the other point around the board while triggering sounds. The most likely points will be all the numerous solder points surrounding any ICs (chips) on the board. Also- try to avoid the contact points that connect to the battery. Not all parts of the circuit can handle a full battery voltage.
How to go about finding a bend point First, get out your screwdriver and remove the back of the device’s housing. At this point, you have several options. Trigger a sound, then: 1. Lick two fingers and touch them to various points on the circuit board. 2. Use your screwdriver to bridge two points 3. Use a wire that’s been stripped at both ends to bridge two points 4. if you want to be more analytical, use a bit of wire with alligator clips at both ends. Anchor it to one point, then touch the other point around the board while triggering sounds. The most likely points will be all the numerous solder points surrounding any ICs (chips) on the board. Also- avoid the contact points that connect to the power supply. Not all parts of the circuit can handle a full battery voltage.
How to make bendsdo your bidding Once you find that bridging two points makes a cool sound, mark them with a sharpie. At this point, you can consider doing a more elaborate modification to the device that starts with attaching a wire to each of the points. The easiest solution from here is to leave the wires like that, and touch them together when you want to bend that point. However, this isn’t very ergonomic and you’ll have pokey wires going everywere. If you were to run those wires to some flat metal objects (like pennies or other copper coins), you could use your fingers to touch the coins and bridge the contacts. This is called a “body contact,” because it uses your skin’s conductivity to bridge the connection.
How to make bendsdo your bidding One of the most common techniques is to then put a switch between the wires that can be turned on/off. From here, it can get complicated. Some people build elaborate patch bays to contain all the interesting points. Others prefer covering the surface of the device in all kinds of switches. Another technique that can create different sounds is to put a variable resistor (potentiometer) connecting the two wires. As resistance is increased/decreased across that connection, the sound will change. More advanced benders will add in other pre-built circuits like oscillators, filters, etc., which can quickly beef up a simple device into formidable synthesis engines.
Tools you will find useful Soldering iron + solder Hot glue gun (for securing your soldered points or holding on knobs) Alligator clips (with wire connecting two of them, preferably) Needlenose pliers A smallish screwdriver
Tools you will find useful Soldering iron + solder Hot glue gun (for securing your soldered points or holding on knobs) Alligator clips (with wire connecting two of them, preferably) Needlenose pliers A smallish screwdriver
Analog electronics We will: • Build a simple oscillator from scratch • Use light-sensitive resistors to create a passive interactive system • Attempt to use this oscillator to control a function in our circuit-bent devices • Experiment with other interactive components
Intro to components:Resistors A resistor is a two-terminal electrical or electronic component that opposes an electric current by producing a voltage drop between its terminals in accordance with Ohm's law: The electrical resistance is equal to the voltage drop across the resistor divided by the current through the resistor while the temperature remains the same. http://en.wikipedia.org/wiki/Resistor
In other words Resistors “slow down” or impede the flow of electricity. The colored bands on a resistor indicate how much resistance they apply. Lower numbers means less resistance. Higher numbers mean greater resistance. http://en.wikipedia.org/wiki/Resistor
Intro to components:variable resistors A potentiometer is a variable resistor. You can change the amount of resistance by turning the rotating shaft. Another type of variable resistor is a light sensitive resistor. http://en.wikipedia.org/wiki/Resistor
Intro to components:Capacitors A capacitor is an electrical/electronic device that can store energy in the electric field between a pair of conductors (called "plates"). The process of storing energy in the capacitor is known as "charging", and involves electric charges of equal magnitude, but opposite polarity, building up on each plate. Capacitors are often used in electrical circuit and electronic circuits as energy-storage devices. They can also be used to differentiate between high-frequency and low-frequency signals. This property makes them useful in electronic filters. http://en.wikipedia.org/wiki/Capacitor
In other words A capacitor is like the shishi-odoshi, a Japanese bamboo fountain (also called a deer-chaser). The bamboo shoot fills up with water, then becomes heavy and tips over, dumping all the water out. It then returns upright and begins filling with water again.
Intro to components:Integrated circuits An integrated circuit (also known as IC, microcircuit, microchip, silicon chip, or chip) is a miniaturized electronic circuit (consisting mainly of semiconductor devices, as well as passive components) that has been manufactured in the surface of a thin substrate of semiconductor material. Only a half century after their development was initiated, integrated circuits have become ubiquitous. Computers, cellular phones, and other digital appliances are now inextricable parts of the structure of modern societies. That is, modern computing, communications, manufacturing and transport systems, including the Internet, all depend on the existence of integrated circuits. Indeed, many scholars believe that the digital revolution brought about by integrated circuits was one of the most significant occurrences in the history of humankind. http://en.wikipedia.org/wiki/Integrated_circuit
Intro to components:555 timer The 555 is an integrated circuit (chip) implementing a variety of timer and multivibrator applications. It was designed in 1970 and was called "The IC Time Machine". It is still in wide use, thanks to its ease of use, low price and good stability. As of 2003, 1 billion units are manufactured every year. The 555 timer is one of the most popular and versatile integrated circuits ever produced. http://en.wikipedia.org/wiki/555_timer
Intro to components:switch, speaker, Led We’ll be using a few other components to round out our oscillator: A switch, A small speaker And a LightEmittingDiode
Oscillate Ur bendings Assuming that we’ve made it this far, at this point we will attempt to attach the oscillator to our bent devices. If successful, new and interesting behaviors will manifest, and will respond to changes in ambient light.
Now what? A number of other environmental sensors exist which can add additional elements of human interactivity: • Piezo discs, which generate voltage when pressure is applied • Accelerometers, which measure motion • Reed switches, which will trigger when the ambient magnetic field exceeds a threshold • These are just a few- there are many others.
Now what? Additionally, the 555 timer can be run in several different modes. One mode can be set up as a single event trigger rather than continuously outputting. Why is this useful? A simple circuit can be built which detects a sudden loud sound (like a gunshot) and triggers the flashbulb of a camera near-instantaneously. Newer ICs called microcontrollers can be programmed to perform specific tasks, and to interface with computer software. The flexibility and potential complexity of these systems makes them an extremely powerful tool.