Tactile objects based on an amplitude disturbed diffraction pattern method

Yuan Liu (1, 2) , Jean-Pierre Nikolovski (2) , Nazih Mechbal (1) , Moustapha Hafez (2) , Michel Vergé (1)

1 LMSP - Laboratoire de Mécanique des Systèmes et des Procédés
2 LIS - Laboratoire Interfaces Sensorielles

Tactile sensing is becoming widely used in human-computer interfaces. Recent advances in acoustic approaches demonstrated the possibilities to transform ordinary solid objects into interactive interfaces. This letter proposes a static finger contact localization process using an amplitude disturbed diffraction pattern method. The localization method is based on the following physical phenomenon: a finger contact modifies the energy distribution of acoustic wave in a solid; these variations depend on the wave frequency and the contact position. The presented method first consists of exciting the object with an acoustic signal with plural frequency components. In a second step, a measured acoustic signal is compared with prerecorded values to deduce the contact position. This position is then used for human-machine interaction (e.g., finger tracking on computer screen). The selection of excitation signals is discussed and a frequency choice criterion based on contrast value is proposed. Tests on a sandwich plate (liquid crystal display screen) prove the simplicity and easiness to apply the process in various solids.

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]

Yuan Liu, Jean-Pierre Nikolovski, Nazih Mechbal, Moustapha Hafez, Michel Vergé. Tactile objects based on an amplitude disturbed diffraction pattern method. Applied Physics Letters, 2009, 95 (25), ⟨10.1063/1.3276549⟩. ⟨hal-00749094⟩