Abstract: A method of sensing touch on a touch surface of a touch structure includes: transmitting, from within an enclosed interior volume, an ultra-sonic transmit signal towards an inner surface of the touch structure that is arranged counter to the touch surface; receiving, from within the enclosed interior volume, an ultra-sonic reflected signal produced from the ultra-sonic transmit signal being reflected by the inner surface; acquiring a plurality of digital samples from the ultra-sonic reflected signal; calculating an Euclidean distance of the plurality of digital samples to a first plurality of reference samples; and determining whether a no-touch event or a touch event has occurred at the touch surface based on the Euclidean distance.

Abstract: A method of configuring a touch sensor includes transmitting an ultra-sonic test signal induced by a first excitation signal towards a touch structure that has a first interface with an enclosed interior volume of the touch sensor and a second interface with an external environment; receiving a plurality of ultra-sonic reflected signals produced from the ultra-sonic test signal and the touch structure, including a first ultra-sonic reflected signal internally reflected by the first interface and a last ultra-sonic reflected signal internally reflected by the second interface; determining a last time of flight corresponding to the last ultra-sonic reflected signal; and selectively configuring a second excitation signal based on the last time of flight. The second excitation signal is used for inducing further ultra-sonic signals.

Abstract: A microelectromechanical device comprising a mass, an electromechanical transducer configured to convert, after damping the mass during a first damping period, displacement of the mass in the first and second directions into corresponding first and second electrical signals during corresponding first and second conversion time periods, a derivative unit configured to generate first and second control signals indicative of the velocity of the mass in the first and second direction, and a controller for providing the first and second control signals to respective first and second one or more electrodes of the electromechanical transducer for simultaneously damping the mass in the first and second directions with a first and second damping forces corresponding to the first and second velocity during the damping time period.

Abstract: A microelectromechanical device comprising a mass, an electromechanical transducer configured to convert, after damping the mass during a first damping period, displacement of the mass in the first and second directions into corresponding first and second electrical signals during corresponding first and second conversion time periods, a derivative unit configured to generate first and second control signals indicative of the velocity of the mass in the first and second direction, and a controller for providing the first and second control signals to respective first and second one or more electrodes of the electromechanical transducer for simultaneously damping the mass in the first and second directions with a first and second damping forces corresponding to the first and second velocity during the damping time period.