The number of viable options for physical control over digital synthesis processes has grown tremendously in recent years. Alongside custom-built hardware controllers, several types of commercially available technologies are being used for this purpose as well. These include multitouch surfaces like the iPad, and an array of hardware originally developed for use with video games, such as Nintendo's Wii remote, the Sony PS3eye camera, and Microsoft's Kinect sensor. In addition to being relatively inexpensive, this technology has the advantage of providing sophisticated sensor data in a standardized format. For a geographically dispersed community of digital artists, standardization and accessibility are often critical. To complement this widely available hardware, there is a need for a standard software library that parses the resulting data streams to further improve accessibility and ease of use. Such tools are very important for remote collaborations in general, but they are particularly needed for digital musical instrument design—a field in which the creator of an instrument is too often its sole performer.
This paper introduces the Digital Instrument Library (DILib) for Pure Data, a library of externals and abstractions that were developed for a course on digital instrument design in the Audio Technology program at American University. DILib is intended to streamline the process of realizing instruments that make use of built-in laptop hardware, accelerometers, infrared fingertip tracking, full body tracking, multitouch surfaces, and other types of interfaces. Each interface abstraction implements a parsing scheme that routes available data to consistently named send variables to be received and applied by users. In some cases, the data is also interpreted before being transmitted. For instance, multitouch trackpad data provided by the laptop interface abstraction is processed by a new external object that preserves continuity of points between each frame of data as it is reported.
DILib will be maintained on a long term basis with the intent of providing designers of new digital musical instruments a stable means of accessing data from an ever-increasing number of control sources. It is hoped that DILib will also facilitate the process of recreating instruments shared by the Pd community.