The Rulers is a self-contained musical performance system called a digital musical instrument [2]. It includes a software component to produce music and a physical interface to manipulate it. Originally designed in 2004 as part of CCRMA's Summer music technology seminar, it is currently undergoing an overhaul so that it is suitable to be played in McGill's Digital Orchestra.

The instrument was designed to evoke the gesture of plucking or striking a ruler that is fixed at one end. Because the seven aluminum “tines” are of various lengths, each tine oscillates for a different amount of time when plucked. This provides an element of visual and passive haptic feedback to the player. The design minimizes the acoustic component of the oscillations and vibrations of the tines. While they oscillate silently, their motion is sensed by infrared reflect sensors to control a computer-based synthesizer. Output amplitude is determined by the amplitude of the tine’s oscillation, allowing control over the amplitude of initial excitation and damping — characteristics that classify it as an instrument that outputs musical events with a non-excited middle [3].

An evaluation of sensor technologies for analyzing the performer gestures was developed resulting on [1]. From this study, a new version is being developed, where mechanical structure, electronic hardware and firmware are being redesigned. For this, we count with the assistance of the following students: Pietro Verrecchia (Electrical Engineering Undergraduate Student at McGill) and Benjamin Cohen (Physics Department at McGill | summer 2011)

1. Carolina Brum Medeiros and Marcelo M. Wanderley. ”Evaluating of sensor technologies for The Rulers, a kalimba-like Digital Musical Instrument”. In Proceedings of the 8th Sound and Music Computing Conference, Padova, Italy, 2011.

2. M. M. Wanderley and P. Depalle, “Gestural control of sound synthesis,” Proc. IEEE, Spec. Issue on Eng. and Music – Supervisory Control and Auditory Communication, vol. 92, no. 4, pp. 632–644, 2004.

3. D. Levitin, S. McAdams, and R. Adams, “Control parameters for musical instruments: A foundation for new mappings of gesture to sound,” Organized Sound, vol. 7, no. 2, pp. 171-189, 2002.