Off the Screen

Electronic Installation Concepts, Issues, Tools, and Materials

Much electronic art is "screen-based" -- visual and aural information presented a via screen and loudspeakers. Today we're going to talk about ways to move the work off of the screen and into the "real world" of physical devices. "Electronic Installation" is a general term for work like this, although it's so broad (and it usually includes screen-based work) that it's not really that useful. Nonetheless, we'll use it.

Since we only have one lecture we're going to have to move through a lot of information very quickly. I'll include links to resources on topics of interest so that you can follow up on your own if you like. The goal here is to give you a sense of what's out there, what's possible, and what people around the CMC (and other places) have been doing in this area. In the process of going through this information we'll talk about lots of pieces that have been created using these ideas.

The most important thing to remember is that Technology is not interesting, it's what you do with technology that is interesting. There's often an urge to use technological gadgets in a piece just because they're cool. Resist the urge! Think through what you're doing, and use what you need.

Basic Concepts and Issues

Once you get your head around some basic concepts it can be pretty easy to add "real world" components to a piece. You can get by with some very rudimentary electronics and mechanical knowledge, and even lacking that there's usually someone around who can help you.

Below we'll go through a number of basic concepts and issues that are good to think about when making an electronic installation.

Performance Modes:

canned/through composed:
A fixed work, like a video loop or CD track, that always does exactly the same thing. *
At least some parts being generated (usually algorithmically) in real time. Pieces with an "internal life." Analog: a solo improvisor. * * *
Implies some sort of behavior that is influenced by viewer or environment. Analog: a conductor directing an orchestra. * * (specifically "Phototropy")
Implies some sort of bi-directional behavioral influence where the viewer/environment influence the system and the system influences the viewer/environment. Analog a group of improvising musicians. * *
This is a rough and semi-arbitrary list. It's not always clear (and it may not even matter) what category a given piece falls into, and many pieces fall into more than one category. The difference between reactive and interactive is subtle but interesting. For me, most work that is called interactive is really reactive. It's very difficult to make a truly interactive system. When making a piece, it's useful to think through what kind of relationship you want it to have with the outside world. A viewer's experience/reaction to a piece can be heavily affected by the claims that the piece makes. Calling something "interactive" sets up certain expectations; they may or may not be expectations that you are prepared to (or want to!) meet.

Physical configurations:

regular computer built into a boxy enclosure. Like an ATM. Often used for browser-based pieces. Pros: very easy to set up, robust, piece works just like it does at home! Cons: often looks dopey, who wants to play with an ATM? People know they're just playing with a computer in a box. BUT, a kiosk doesn't have to be dopey. * *
behind the scenes:
gear hidden away somewhere. Lots of magic. Often used for performances, interactive works. Pros: can use lots of gear, no space issues, tech doesn't get in the way of presentation. Cons: can make troubleshooting much harder, can make piece seem "mysterious" -- too much magic can lead to skepticism. *
crap everywhere. Often used in performances. Pros: crap everywhere. Cons: crap everywhere. *
components embedded/built in to the work itself. Often used in electronic sculpture, robotics, custom instruments. Pros: can make for a very cohesive piece, simplified installation, everything in one place, good for small spaces, stand alone installations, non-tethered works. Cons: often requires more work, specialized design, microcontrollers. * * *
Obviously the physical presentation of a piece is pretty important. What's your goal? What should people focus on? Does it matter if they know that they're playing with a Flash movie stuck inside an elaborate box? Should the innards of the piece be visible? Should it be magic? Raw? Should people think "technology" when they see your piece? Should they think "computer?" Does it matter to the piece?

You also need to think about protecting the piece itself. If there are lots of wires and gadgets sitting around, people will mess with them. If you leave your piece running on an unprotected computer, people will quit it and start playing games and displaying porn instead of your piece. How do you want people to relate to the piece, and how do you want the piece to relate to people?

Types of Sensing:

sensors are worn, actively manipulated, observed, by participants. Participants consciously produce the environment that is being sensed. Think joystick, mousepad, switch, touchscreen, wired dancers, sensortized instruments, exposed video camera, etc. * *
sensors are embedded in the environment. Participant influence on sensed environment is not conscious or directed. Think temperature sensor, ambient light detector, hidden video camera, etc. * *

Device Types and Protocols:

computer: we all know what this is.
microcontroller: cheap, tiny computer with minimal i/o, no operating system.
sensor: transmits information from the environment to the piece.
actuator: transmits information from the piece to the environment.
MIDI: a protocol for communicating between musical (and other) devices. Widely used and supported by major electronic equipment manufactures. *
serial communication: a generic technique for transferring digital information from one device to another. "Serial" means that the bits that represent each byte of digital information are sent one after another. This is slower than "parallel" (see below) but much easier to configure and manage. *
parallel communication: a generic technique for transferring digital information from one device to another. "Parallel" means that the bits that represent each byte of digital information are sent all at the same time. This can be fast and easy for very simple pieces, but quickly become unwieldy in larger projects. *
ethernet: a type of network connection. Most computers are connected to the internet via ethernet. *
wireless/WIFI/bluetooth/etc: a variety of methods for transferring digital information from one device to another without the use of wires.
It's not a long list! Generally, you've got something acting as the "brain" of the piece, you've got components feeding information to/from the brain, and you've got something hooking it all together.

Often the easiest way to drive a complex piece is to just use a computer. Many people keep old machines around just for this purpose. Microcontrollers can be cooler, but they're harder to work with. You've got to learn how to hook them up, how to program them. But they're supercheap and reliable (no moving parts!) and are a good choice for self-contained works that need to be very robust and reliable. They're also good when making multiples.

There are all sorts of sensors and actuators available. Most of the time they're meant for industrial/commercial applications. The fun part is co-opting them for strange experiments. Sensors sense, actuators act.

The various communication protocols are mostly just variations on the same theme. Your choice depends on a number of variables, such as interoperability with commercial equipment, speed needs, transmission distance, autonomy.

Practical considerations:

You've got to think about how/where/when/by and to whom the piece will be presented. It's easy to make something that works great in your studio. But how is it going to work in a gallery or on stage or in a subway tunnel?

Some questions to ask yourself: Does the piece have to be able to run by itself? Will there be someone there to reset it if it crashes? How do you start it up and shut it down? How reliable is it? How long can it run continuously? How do you know if it's working correctly? Is it fault tolerant? Can the audience accidently crash it? How about on purpose? Should you build in a "fake mode?" Does it need special resources, like a net connection, consistent lighting, or a quiet environment? Will people be tempted to walk off with parts of it? Will your personal equipment be part of the piece? How long can you stand having your laptop sit in a kiosk somewhere? Is this a permanent installation, or will the piece disappear after it's shown? Can you reuse parts of the installation in other work? Can you make your design modular to facilitate reuse and repair?

What will a day in the life of the piece be like? Get into the anthropomorphic spirit and try to preemptively solve as many of these problems as you can.

Down and Dirty: Tools and Materials

In this section we'll talk more specifically about some of the tools and materials used to make electronic installations. We don't have time to get too specific on any of these topics. The goal here is to help you think through what you want to do so that you can focus on the topics that are relevant to your work. Most artists learn how to do this kind of work through trial and error, picking up new skills and techniques as they move from piece to piece. It's too large a topic to learn all at once. Figure out what it is you want to do, then find out how to do it. Be patient, and after a few pieces you'll find that you suddenly know how to do a lot more than you expected!


There's a computer involved in one way or another in most electronic installations.
cheapo machines: As mentioned above, the processing power needed for many works is pretty modest, so older computers can often be used. That's nice because older computers are a lot cheaper than new ones, and if it's not your main personal machine it won't be too much of a burden to dedicate the computer to the piece. If you're doing fairly simple things like reading switches and turning some motors on and off, then you can probably get by with a $50 PC from a thrift shop. If you need to run commercial software like Director or Max, then you'll need a slightly newer machine. Still, a five year old Mac will run an older version of Director or Max just fine, and will often do what you need it to do. If you're writing your own software in C then an old machine can be perfect for many motion control and sensing tasks. It's pretty easy to find cheap old machines online or at thrift stores and yardsales.

not-so-cheapo machines: If your piece is very elaborate and involves live video/audio processing and the like, then you'll probably need an up-to-date machine. There's a lot that can happen to a computer that's being used in an installation or performance. If you're using your personal machine, make sure that you have all of your data backed up before subjecting the machine to the real world. Also be aware that if your machine is publicly accessible (as in a kiosk or web-based installation) people will try to dig around on your system. Do you want gallery patrons reading your saved emails?

If your piece will be up for more than a few days you should think about renting a computer or asking the gallery/space to loan you one. If you end up using someone else's computer BEWARE: even if it's the same kind of machine as the one you've developed the piece on there's a good chance that things will be screwy. Get your hands on the loaner machine as soon as possible. Insist an at least a few hours of debugging time in addition to the time it normally takes to set up the piece. Some simple application or utility (like a key mapper or a cron job) installed on the loaner machine can easily cause mysterious problems.

laptop or desktop? Desktop machines are generally more robust than laptops. They're easier to keep cool and they tend to have more i/o options built in (serial ports, parallel ports, monitor outputs, USB, firewire, etc). Since they're larger, they're less likely to walk away when no one is looking. Laptops, on the other hand, can be much easier to transport, and easily fit in small or awkward places with no giant monitor to get in the way.


Microcontrollers rock. These are the little computers that run the world. They're in your microwave, your watch, all over your car, probably in your sneakers, soon to be in your cat.
computer or microcontroller? If you need to do high-level things like video or sound processing, heavy data analysis, webserving, video projection, etc., then you should probably use a regular computer. If your needs are more modest things like interfacing with sensors, controlling actuators, driving robotics, basic information processing, etc., then a microcontroller might do the job. Many times microcontrollers and regular computers are used together. The microcontroller might be responsible for talking to a bunch of sensors, doing some basic processing and formatting of the data, and then sending it on to the computer for analysis and response. Or a computer might send some commands to a microcontroller, which then controls some other devices like a DVD player or a rotating speaker. Regular computers are good for high-level tasks; microcontrollers are good for low-level tasks.

the upside: Microcontrollers are small and cheap and pretty much indestructible (no moving parts!) They range in size from less than 1/4" to a couple inches. They use very little power, and can run for days on a battery or be solar powered. They range in cost from < $3 to about $50 each. Higher end models are fast enough to play sounds, analyze sensor data, drive displays, etc. It's easy to hook a bunch of microcontollers together to form a network. Given their small size and low cost they're easy to use in multiples. Many microcontrollers have everything you need built into them so that there's very little circuit design, soldering or other electronics knowledge needed to use them. There's lots of free information and software available online. Since they're designed for industrial uses, they're great for stand alone, autonomous pieces that need to run unattended for long periods of time.

the downside: They don't run MacOS or Windows or even Linux. You have to do some fairly low-level programming and learn a bit about electronics to use them. They're not super fast or powerful and can't handle video (although they can control video devices, like DVD players and projectors).

types of microcontrollers:

The Basic Stamp from Parallax is the most popular "high level" microcontroller for artists just starting out. The company that makes them has lots of educational materials online, and they make kits and modules that are super easy to use. Many people make pieces just using "off-the-shelf" Basic Stamp kits. They are programmed in the BASIC language, which is simple and easy to learn even for non-programmers (although once you've got a bit of experience it will start to drive you mad). The downside of the Basic Stamp is that it's slow and expensive (about $50 each).

Basic Stamp knockoffs: There are a bunch of companies that have products similar to the Basic Stamp. These include the BasicX, Basic Atom, etc. These don't have the same level of community support as the Basic Stamp, but if you're on a budget it's worth checking out some of the alternatives.

Atmel AVR and PIC: These are two brands of "low level" microcontrollers. In fact, the Basic Stamp is built on top of a PIC microcontroller. Because these are lower level, they're faster, cheaper, and smaller. That also means they can be a bit harder to work with. They can be programmed in BASIC, C, assembly, java, etc. Depending on the language/chip you may have to pay for a compiler. I use the Atmel AVR chips in all of my work.

High level or low level? If you plan to do a lot of work with microcontrollers and/or you need a lot of them, then you should look at the AVR and PIC chips. If you just need something working quickly and it's a one-time thing, then the Basic Stamp is probably a better bet.
Whatever microcontroller you end up using, you'll need a development environment to work with it. That usually means a special board for programming the chip, a cable to attach the board to your computer, and software for writing/testing/debugging the program. You can usually buy a development board at the same time you buy your first microcontroller. Often people end up using the development board in their pieces. That's okay if the piece is a one-time thing or if it's well-protected. But for a permanent piece or a piece that needs to be robust, you'll want to build or buy a separate circuit board for each piece.


Sensors sense their environment and report their findings via electrical signals. There are many different kinds of sensors and many different ways to read their signals. Luckily, despite the variety, most sensors can be used in similar ways so that once you know how to use one you can figure out how to use many others.
general sensor types:
analog/variable resistors: many simple environmental sensors work as variable resistors (VR). That means that as the element being sensed changes, the effective resistance of the sensor changes. The resistance of the sensor affects how current flows through a circuit. It's easy to use a microcontroller to observe these changes in current flow, so it's easy to use a microcontroller to keep track of the element being sensed. Most analog sensor are variable resistors, although some work in other ways (see "piezo element", below.)

digital: some simple and most complex sensors are digital, meaning they output information about the element they're sensing in encoded digital form. A microcontroller receives that information and then decodes it to keep track of the element being sensed. Some complicated sensors contain microcontrollers themselves! Digital sensors are usually pretty easy to use, although there's more that can go wrong than there is with analog sensors. Digital sensors also tend to be more expensive. The trade off is that they can be sense more exotic/complex elements of the environment than simple analog sensors can.

video: now that real-time video is fairly easy to do on consumer computer hardware, video-based sensing has become a viable alternative. Video-based sensing involves analyzing a video image to determine aspects of the captured scene, such as the positions of objects and their relationships. Some of the sensing functions normally accomplished with analog/digital sensors can now be done more simply and accurately via video tracking. That said, video sensing can be sometimes be much more complicated, expensive, and unreliable than simpler forms. It all depends on the application/environment.

some sensors:
photo cell: light levels * *
pressure pad: applied pressure, comes in many forms *
temperature sensor: ambient temperature
bend sensor: degree of bend * *
button/switch: on/off
tilt switch: tilt/angle
potentiometer: dial/knob rotational position *
joystick: 2-D position of stick *
slider: 1-D position of knob *
piezo element: vibration, AKA "contact mic". Piezo elements put out a voltage when they're deformed. Useful! *
distance sensor: distance to object, presence of objects
compass: direction
accelerometer: acceleration, orientation *
graphics tablet: pen position, pressure, tilt. *
video: *
motion tracking: where's the object? How fast is it moving? Where is it going?
object identification: what is that? Is it a face? Who's? Where are the eyes?
scene analysis: what's going on here?


Sensors sense the environment, actuators alter it. Actuators come in many, many forms. Pretty much anything that you might call an "output" can be considered an actuator. Monitors, printers, and speakers are all actuators. We'll focus more specifically on lower-level actuators.
general actuator types:
movement: push, pull, spin, open, close, throb, flow, etc.
light: various devices that emit photons. Not just monitors!
sound: various devices that cause things to vibrate at audible frequencies
current: various devices that work like electronic switches.
some actuators:
motors: AC, DC, stepper, servo. Motors spin. Spin can be translated into all sort of motion. *
solenoids: push, pull, jerk, swing. *
Liquid Crystal Display: like on a calculator (grey) or a laptop (color). Come in many sizes.
Light Emitting Diode: blinky lights on your modem. Many sizes/shapes/colors. *
LED display: like on a digital clock. Come with various numbers of segments for making characters.
ElectroLuminescent strips: glow in freaky colors when activated. *
Cathode Ray Tube: television
magnetic: magnets wiggle in the presence of an electro-magnetic field. Most speakers are magnets. *
piezo element: piezo elements deform when voltage is applied. Apply a changing voltage and they work like speakers. See above for opposite microphone effect.


That's our whirlwind tour through the world of electronic installations. Hopefully you're all jacked up now and can't wait to go get a soldering iron and start making a mess of things. Have fun!