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Creative Systems as blocks and lines – Case Study of Pulse Room by Rafael Lozano–Hemmer

by Guillermo Montecinos


Everytime I try any kind of installation or creative experience, the first thing I do is guessing what is the logic system behind the output I have in front of me. I analyze the piece not only conceptually, but in terms of what inputs are being considered, where from, how the system is parsing these inputs and how the output is being processed. I like to guess the type of sensors and actuators used, as well as the computational engine behind the scenes.

In this blog post I will describe my approach to sistematize a creative system as a network of blocks with inputs and outputs, and connectors –that represent data paths within the system. The introduction is my take on the importance of understanding the world as a representation of blocks, and this framework will be used to analyze Pulse, an artwork by the Mexican-Canadian artist Rafael Lozano–Hemmer.

Analyzing the world as blocks

Any system –whatever actions it performs– can be understood as a box or a set of boxes whose behavior is unknown, that takes an input and uses it to generate an output. This is the simplest system we can have:

Simplifying complex systems into arrays of blocks that encapsulate operations is a great approach inspired on the strategy Divide-and-conquer, which solves a problem by dividing it into multiple sub-problems.

I usually attempt to guess which are the logical steps or operations on a system, then represent them as boxes and connect them depending on the process flow. Let's check out a couple examples.

Shannon's model of communication – An example

An example that profoundly calls my attention is Shannon's model of communication (1948) because of how simply it explains a complex interaction as communication. The model sistematizes the process of communication between an emissor and a receiver as a series of boxes and arrows that describe a flow of information. The Information Source –let's say you– emmits a message which is sent over the communication channel by the Transmitter –let's say your phone. The Transmitter receives the Message converts it into a Signal. Then, the Signal gets into the communication chanel (the box in the center) which also receives the noise coming from a Noise Source, that represents electrical/digital uncertainty and interference over a communication channel. Subsequently, the Receiver takes the Received Signal which is the Signal after being affected by noise, and converts it in a Message received at the Destination.

With a simple diagram composed by boxes and arrows Shannon ilustrated a logical flow of information where an Input is affected by a System and then converted to an Output. We can go further and simplify Shannon's model by detecting which are the input, output and system. It's clear that the input is the message incoming from the Information Source, while the output is the message getting to the Destination. Then, the System –in our analysis– is composed of the Transmitter, the Noise Source, the channel and the Receiver.

Jim Campbell's Formula for Computer Art

Formula for Computer Art is an animated piece by the artist Jim Campbell that –quoting Golan Levin"mischievously implies that the inputs to many data-mapping artworks may be fundamentally arbitrary and thus interchangeable". Even though the piece criticizes the flexibility and arbitrariness in which interactive systems can be designed, it uses the formal language of diagrams, so we can use it as a guide to think about systems.

I encountered this diagram/piece while researching Lauren McCarthy's's Critical API's class she taught at ITP on 2016. I strongly recommend to check her work out, both as an artist and educator.

According to the piece's logic, all possible inputs on the left can be captured by sensors and converted into data signals understandable by the systems. Anytime an input is received, it triggers an input interrupter that let's the algorithms know a new input signal came in. Those signals are processed by the algorithms, stored in memory and combined with data already stored to generate an output signal. A new output signal executes an output controller that represents it in the real world.

Based on the above we can say that the system is everything that takes place after the input signals are interpreted by the sensory devices, and before the output signals are represented in the physical world. Then, Jim Campbell's artwork can be reinterpreted as a framework that will help us design and analyze systems.

Case study: Pulse Room – Rafael Lozano–Hemmer

Let's apply what we have discussed on an actual piece. Pulse Room is an interactive installation by the artist Rafael Lozano-Hemmer, that enables users see their heart beat represented on a illumination system in a large room, conformed by hundreds of incandescent bulbs hanging from a cable 3 meters above the audience. When someone holds the interface, a computer detects his or her pulse and immediately sets off the closest bulb to flash at the exact rhythm of his or her heart. (video)

Inputs and Outputs

According to the piece's description, the system's input is the human heart beat measured by a sensor, which converts the heart pulse into an electrical pulse. It can be subject of debate whether the system input is the actual heart beat or its representation into electrical signals, which obviously affects the way we understand the sensor as part of the system or not. If we follow Formula for Computer Art, the sensor would be out of the system, but in this case let's understand the sensor as a part of the system.

On the other hand, the system's output is the effect of hundreds of light bulbs dancing at the user's heart pulse. Thus, the output devices are the light bulbs and the output signals that control their behavior are the electric signals emitted by the dimmer packs.

Processing Units

Let's break down the system into process units. The primary process of this system can be identified as the transduction of the heart pulse into an electric pulse, which is performed by the input sensor. Then a secondary process is the conversion of this pulse into a USB-readable digital signal, performed by an Analog to Digital Converter (ADC), mentioned in the installation's technical documentation as a Go!Link adapter.

Then, the heart beat rate is used to generate a pulse-like electrical signal that dims the bulbs array simulating the spatialization of the heart beat. This tertiary step –that conforms the system's main process– runs on a computer and outputs not a single signal, but an array of signals that control each bulb.

Finally, a quaternary process consists of delivering the control signal to each bulb, which is performed by a set of signal routers that feed an array of wires, that controls all the bulbs on the installation. Since this stage requires stable lightning management, it seems reasonable that the artist decided to use DMX dimmer boxes, which are actuators that demux a series of control signals transmitted by one cable into a series of power signals that fed each bulb. Please note that due to DMX's architecture, the wiring between the laptop (main process) and the dimmer packs has to be set as a chain of packs.

Communication protocol

It seems clear that the only stage where a particular communication protocol is needed to be used, is between the laptop and the DMX dimmer packages, whichh has to be DMX because the implementation of them forces the protocol. DMX is a standard for digital communication networks commonly used for stage lightning (for further information visit DMX on Wikipedia or watch this informative DMX Lighting Tutorial).

System Diagram