Haptic Interaction with a Digital Waveguide String

Edgar Berdahl

We are studying how to implement the interaction shown on the left using the PHANTOM robotic arm shown on the right.

Technical information
E. Berdahl, G. Niemeyer, J. O. Smith III. Using Haptic Devices to Interface Directly with Digital Waveguide-Based Musical Instruments,
Ninth International Conference on New Interfaces for Musical Expression,
Pittsburgh, PA, June 4-6, 2009.

Sample sounds

Often it is easiest to implement the instrument using the hybrid approach. On the left, you hear the virtual model sound, while on the right you hear the sound recorded by a microphone placed next to the robotic arm's motors. The motor sound is lowpass filtered so that you cannot hear the PWM signal used to control the motors. (If you really want, you can hear the unprocessed version here, where the PWM noise interference signal is louder.)
The explicit approach provides for a more accurate physical interaction with the virtual string. The string can be damped when the musician holds his or her finger against the virtual string. (If you really want, you can hear the unprocessed version here with PWM noise.)
The virtual string is bowed via the haptic interface. You hear the sound coming directly out of the virtual model.

To Edgar Berdahl's Web Page

To Julius O. Smith III's Web Page