Strings On-Line

An interactive art installation presented during the International Conference on New Interfaces for Musical Expression (NIME) 2020.

guitars and robots

The installation is based on a collection of self-playing guitars and interactive robots.

Conceptual information

This physical-virtual installation explores the concept of entrainment in a setup with six self-playing guitars and three distance-controlled Dr Squiggles robots. The installation is physically located in the fourMs Lab at the University of Oslo, Norway. Users watch an online video stream of the installation with binaural audio, and can interact with the robots (and indirectly with the guitars) through a web interface.

Each of the guitars is equipped with a small computer that plays sounds through an actuator mounted on the back of the instrument. The guitars also contain a built-in microphone, through which they listen to their surroundings, and respond sonically to what they hear. The guitars hang in thin lines from the ceiling, and are therefore free to (slowly) spin around. The sonic result is a complex interplay between rhythm and chaos, structure and variation.

People are invited to interact with three Dr Squiggles robots sitting next to the guitars. The interaction is happening through a simple web interface. By the push up of a button, the robots will play on metal rods, and these sounds will be picked up by the guitars. As such, the installation blurs between the physical and the virtual, local and global, and it plays with conceptions of differences between acoustic and digital instruments.

Technical information

Guitar with micro-computer
The Bela micro-computer on the guitar

Each of the guitars is equipped with a Bela micro-computer, which produces electronic sound through an actuator placed on the back of the guitars. There are no external speakers, all the sound generation is coming from the vibration of the acoustic guitar. The sound is created through a physical model (the Karplus Strong algorithm). The guitars listen to their environment through a microphone, and uses a Firefly-inspired algorithm to entrain to each other. The pitch of the tones and colour of the light is controlled through an infrared distance sensor.

Each of the Dr Squiggles robots has eight legs, with a motor attached to them, through which they can tap on objects to create rhythmic patterns. They have a powerful onboard computer (Raspberry Pi), and are therefore fully autonomous, enabling explorations of swarm-like activities. For the installation, each of the robots can be controlled remotely through a web interface.

The streaming is done through a Zoom webinar. We tried different types of streaming solutions, including on the main video platforms, but none of them provided a low enough latency (most of them have many seconds of latency). So we decided to go for a Zoom solution, which is a good compromise between quality and latency. Unfortunately, the browser version of Zoom is not as optimized as the standalone version. So, even though it is not ideal to have two windows open at the same time, we decided to go for the standalone Zoom version and a separate control window.


RITMO and fourMs Lab
Published June 21, 2020 9:04 PM - Last modified July 21, 2020 1:31 PM