A dialysis machine comprising: one or more processing units configured to transmit control data; a pump (132, 192) configured to pump medical fluid to and from a patient based at least in part on control data received from the processing unit; an electronic panel comprising: a display surface, and at least one panel control unit configured to cause the electronic panel to display at least one user interface element (204a-c) that can be invoked by a user; at least one projector; and at least one camera; wherein the one or more processing units are configured to: process input received by the camera, determine a location of a physical object in a field of view of the camera based on the processed input, determine whether the physical object is a physical object of interest, wherein such determination is based on a width of the physical object being not greater than a predetermined threshold, for the physical object being an object of interest, determine, based on processed input received on at least one occasion, that the location of the physical object represents an invocation of the at least one user interface element (204a-c) displayed on the electronic panel, and determine the control data based on the processed input. one or more processing units configured to transmit control data; a pump (132, 192) configured to pump medical fluid to and from a patient based at least in part on control data received from the processing unit; an electronic panel comprising: a display surface, and at least one panel control unit configured to cause the electronic panel to display at least one user interface element (204a-c) that can be invoked by a user; a display surface, and at least one panel control unit configured to cause the electronic panel to display at least one user interface element (204a-c) that can be invoked by a user; at least one projector; and at least one camera; wherein the one or more processing units are configured to: process input received by the camera, determine a location of a physical object in a field of view of the camera based on the processed input, determine whether the physical object is a physical object of interest, wherein such determination is based on a width of the physical object being not greater than a predetermined threshold, for the physical object being an object of interest, determine, based on processed input received on at least one occasion, that the location of the physical object represents an invocation of the at least one user interface element (204a-c) displayed on the electronic panel, and determine the control data based on the processed input. process input received by the camera, determine a location of a physical object in a field of view of the camera based on the processed input, determine whether the physical object is a physical object of interest, wherein such determination is based on a width of the physical object being not greater than a predetermined threshold, for the physical object being an object of interest, determine, based on processed input received on at least one occasion, that the location of the physical object represents an invocation of the at least one user interface element (204a-c) displayed on the electronic panel, and determine the control data based on the processed input.