Abstract: Actuation sensor apparatus configured to removably attach to a liquid dispenser, the apparatus comprising (a) an electronic circuit including a dispense sensor and a wireless transmitter and (b) a power supply for the electronic circuit, whereby, when dispenser actuation occurs, an identification code unique to the apparatus is wirelessly transmitted to a receiver. In a preferred embodiment, the dispense sensor is a magnetic sensor and the apparatus further includes an actuator arm having a magnet, and the actuator arm is configured to move with respect to the magnetic sensor during actuation.