An electronic device includes a touch-sensitive display, and a plurality of piezoelectric patch transducers disposed beneath the display. A controller is configured to switch each of the transducers between a tactile feedback mode to provide tactile feedback via the touch-sensitive display, and an object detection mode to provide acoustic detection of a contactless position of an object relative to the device. The object is free of contact with the device at the contactless object position. Using the same transducers to provide tactile feedback and object detection provides these features without additional costs associated with adding further components. A microphone of the device can receive ultrasonic signals, emitted from the transducers and via associated acoustic ports, and the device can process the received signals to determine a contactless three-dimensional gesture that is performed, for example above the display.