A liquid dispenser comprising: a liquid pump, in turn comprising: a first liquid inlet configured to allow the introduction of a first liquid into a mixing chamber, a second liquid inlet configured to allow the introduction of a second liquid into the mixing chamber, an outlet valve configured to regulate the release of a mixed liquid from the mixing chamber, the mixed liquid being a blend of the first liquid and the second liquid, a reciprocating member configured to effect a reciprocating movement along a longitudinal axis, the reciprocating movement alternately comprising a first movement and a second movement opposite the first movement, the reciprocating member being configured such that the outlet valve closes when the reciprocating member completes the first movement and such that the outlet valve opens when the reciprocating member completes the second movement, and a liquid outlet configured to allow the release of liquid when the outlet valve is open;and a piezoelectric detector arranged in such a way that when the liquid pump generates a shockwave, the shockwave is detected by the piezoelectric detector, the piezoelectric detector generating a voltage peak which is a function of the shockwave. a liquid pump, in turn comprising: a first liquid inlet configured to allow the introduction of a first liquid into a mixing chamber, a second liquid inlet configured to allow the introduction of a second liquid into the mixing chamber, an outlet valve configured to regulate the release of a mixed liquid from the mixing chamber, the mixed liquid being a blend of the first liquid and the second liquid, a reciprocating member configured to effect a reciprocating movement along a longitudinal axis, the reciprocating movement alternately comprising a first movement and a second movement opposite the first movement, the reciprocating member being configured such that the outlet valve closes when the reciprocating member completes the first movement and such that the outlet valve opens when the reciprocating member completes the second movement, and a liquid outlet configured to allow the release of liquid when the outlet valve is open;and a first liquid inlet configured to allow the introduction of a first liquid into a mixing chamber, a second liquid inlet configured to allow the introduction of a second liquid into the mixing chamber, an outlet valve configured to regulate the release of a mixed liquid from the mixing chamber, the mixed liquid being a blend of the first liquid and the second liquid, a reciprocating member configured to effect a reciprocating movement along a longitudinal axis, the reciprocating movement alternately comprising a first movement and a second movement opposite the first movement, the reciprocating member being configured such that the outlet valve closes when the reciprocating member completes the first movement and such that the outlet valve opens when the reciprocating member completes the second movement, and a liquid outlet configured to allow the release of liquid when the outlet valve is open;and a piezoelectric detector arranged in such a way that when the liquid pump generates a shockwave, the shockwave is detected by the piezoelectric detector, the piezoelectric detector generating a voltage peak which is a function of the shockwave.