Apparatus comprising: a touch panel (1, 21, 28, 33, 38) which comprises a layer of piezoelectric material disposed between a plurality of sensing electrodes (5, 23, 24) and at least one counter electrode; a touch controller connected to the touch panel, and configured to determine, in response to receiving piezoelectric signals from one or more of the sensing electrodes, a location and an applied force corresponding to a user interaction with the touch panel; wherein the touch controller is further configured to determine a capacitance value of one or more of the sensing electrodes; characterized in that the touch controller is configured to: in response to receiving piezoelectric signals and determining no changes in the capacitance values for any of the sensing electrodes, to operate in a force-based mode wherein the touch controller is configured to determine a location and an applied force corresponding to a user interaction based on the piezoelectric signals; in response to determining changes in the capacitance values of one or more sensing electrodes and receiving no piezoelectric signals, to operate in a capacitance-based mode wherein the touch controller is configured to determine a location corresponding to a user interaction based on the determined changes in the capacitance values; in response to determining changes in the capacitance values of one or more sensing electrodes and receiving piezoelectric signals, to operate in a mixed force-capacitance mode wherein the touch controller is configured to determine a location corresponding to a user interaction based on the determined changes in the capacitance values and to determine an applied force corresponding to the user interaction based on the piezoelectric signals. a touch panel (1, 21, 28, 33, 38) which comprises a layer of piezoelectric material disposed between a plurality of sensing electrodes (5, 23, 24) and at least one counter electrode; a touch controller connected to the touch panel, and configured to determine, in response to receiving piezoelectric signals from one or more of the sensing electrodes, a location and an applied force corresponding to a user interaction with the touch panel; wherein the touch controller is further configured to determine a capacitance value of one or more of the sensing electrodes; characterized in that the touch controller is configured to: in response to receiving piezoelectric signals and determining no changes in the capacitance values for any of the sensing electrodes, to operate in a force-based mode wherein the touch controller is configured to determine a location and an applied force corresponding to a user interaction based on the piezoelectric signals; in response to determining changes in the capacitance values of one or more sensing electrodes and receiving no piezoelectric signals, to operate in a capacitance-based mode wherein the touch controller is configured to determine a location corresponding to a user interaction based on the determined changes in the capacitance values; in response to determining changes in the capacitance values of one or more sensing electrodes and receiving piezoelectric signals, to operate in a mixed force-capacitance mode wherein the touch controller is configured to determine a location corresponding to a user interaction based on the determined changes in the capacitance values and to determine an applied force corresponding to the user interaction based on the piezoelectric signals. in response to receiving piezoelectric signals and determining no changes in the capacitance values for any of the sensing electrodes, to operate in a force-based mode wherein the touch controller is configured to determine a location and an applied force corresponding to a user interaction based on the piezoelectric signals; in response to determining changes in the capacitance values of one or more sensing electrodes and receiving no piezoelectric signals, to operate in a capacitance-based mode wherein the touch controller is configured to determine a location corresponding to a user interaction based on the determined changes in the capacitance values; in response to determining changes in the capacitance values of one or more sensing electrodes and receiving piezoelectric signals, to operate in a mixed force-capacitance mode wherein the touch controller is configured to determine a location corresponding to a user interaction based on the determined changes in the capacitance values and to determine an applied force corresponding to the user interaction based on the piezoelectric signals.