Abstract: An electronic device (1) such as a cell phone, or a proximity detector for an electronic device (1), has an ultrasound transmitter (5), an ultrasound receiver (6), and a processing system. It transmits an ultrasonic sine-wave signal from the transmitter (5), and receives the ultrasonic sine-wave signal, through air, at the receiver (6). It detects when the frequency of the transmitted signal and a frequency of the received signal satisfy a predetermined difference criterion, and uses this to determine whether to disable or enable a touch or touchless input (2) on the device (1).

Abstract: An electronic device (1) such as a cell phone, or a proximity detector for an electronic device (1), has an ultrasound transmitter (5), an ultrasound receiver (6), and a processing system. It transmits an ultrasonic sine-wave signal from the transmitter (5), and receives the ultrasonic sine-wave signal, through air, at the receiver (6). It detects when the frequency of the transmitted signal and a frequency of the received signal satisfy a predetermined difference criterion, and uses this to determine whether to disable or enable a touch or touchless input (2) on the device (1).

Abstract: An electronic device comprises an ultrasound transmitter, an ultrasound receiver, a display screen, and a processing system. It transmits ultrasonic signals from the ultrasound transmitter and receives ultrasound signals, through air, at the ultrasound receiver. It uses signals transmitted by the ultrasound transmitter and received at the ultrasound receiver to determine, at intervals, whether or not an object is present within a three-dimensional detection zone adjacent the device, by determining whether or not a set of presence conditions is met. It alters the display screen when the results of two successive such determinations differ. It also uses signals transmitted by the ultrasound transmitter and received at the ultrasound receiver to detect a movement of an input object, and control a further operation of the device in response to said detection.

Abstract: An electronic device comprises an ultrasound transmitter, an ultrasound receiver, a display screen, and a processing system. It transmits ultrasonic signals from the ultrasound transmitter and receives ultrasound signals, through air, at the ultrasound receiver. It uses signals transmitted by the ultrasound transmitter and received at the ultrasound receiver to determine, at intervals, whether or not an object is present within a three-dimensional detection zone adjacent the device, by determining whether or not a set of presence conditions is met. It alters the display screen when the results of two successive such determinations differ. It also uses signals transmitted by the ultrasound transmitter and received at the ultrasound receiver to detect a movement of an input object, and control a further operation of the device in response to said detection.