An apparatus, comprising: a touch interface comprising: a plurality of electrodes ; and a shield device , which is configured to be driven to a common voltage and is configured to establish a first mutual capacitive coupling with a first electrode of the plurality of electrodes ; and establish a second mutual capacitive coupling with a second electrode of the plurality of electrodes ; and a controller coupled to the touch interface , the controller configured to: a) detect a touch based on a detected first capacitance value of the first mutual capacitive coupling and a detected second capacitance value of the second mutual capacitive coupling, b) detect the touch in response to the detected first capacitance value, the detected second capacitance value, or a combination thereof satisfying a touch detection threshold; characterised in that the controller is further configured to c) increase the touch detection threshold in response to detecting liquid on the touch interface ; and d) determine that liquid is present on the touch interface in response to determining that the detected first capacitance value and the second detected capacitance value indicate that multiple buttons of the touch interface have been touched concurrently. a touch interface comprising: a plurality of electrodes ; and a shield device , which is configured to be driven to a common voltage and is configured to establish a first mutual capacitive coupling with a first electrode of the plurality of electrodes ; and establish a second mutual capacitive coupling with a second electrode of the plurality of electrodes ; and a plurality of electrodes ; and a shield device , which is configured to be driven to a common voltage and is configured to establish a first mutual capacitive coupling with a first electrode of the plurality of electrodes ; and establish a second mutual capacitive coupling with a second electrode of the plurality of electrodes ; and establish a first mutual capacitive coupling with a first electrode of the plurality of electrodes ; and establish a second mutual capacitive coupling with a second electrode of the plurality of electrodes ; and a controller coupled to the touch interface , the controller configured to: a) detect a touch based on a detected first capacitance value of the first mutual capacitive coupling and a detected second capacitance value of the second mutual capacitive coupling, b) detect the touch in response to the detected first capacitance value, the detected second capacitance value, or a combination thereof satisfying a touch detection threshold; a) detect a touch based on a detected first capacitance value of the first mutual capacitive coupling and a detected second capacitance value of the second mutual capacitive coupling, b) detect the touch in response to the detected first capacitance value, the detected second capacitance value, or a combination thereof satisfying a touch detection threshold; c) increase the touch detection threshold in response to detecting liquid on the touch interface ; and d) determine that liquid is present on the touch interface in response to determining that the detected first capacitance value and the second detected capacitance value indicate that multiple buttons of the touch interface have been touched concurrently. <EOS>