An embodiment of the invention relates to an apparatus for dispensing liquid, which apparatus detects an object and controls the dispensing of liquid. The apparatus includes a first signal source which generates a first beam pulse and a second signal source which generates a second beam pulse and the propagation paths of the beam pulses intersect in relation to each other. The apparatus also includes a receiver which receives reflected parts of the first beam pulse and receives reflected parts of the second beam pulse, the parts reflected from the first and second beam pulses being reflected from the object which is located on the propagation path of the first and the second beam pulse. Furthermore, the system comprises a signal processing unit detects said object based on the parts reflected from the beam pulses and, based on this detection, controls the dispensing of liquid.