controlled by a control circuit 18 shown in fig3 b connected to the piezo electric pump control terminals 17 the control circuit 18 acts as a control device for the piezoelectric pump 8 and comprises a cpu 19 a rom 20 a ram 21 a voltage detection circuit 22 and a driving voltage output circuit 23 the rom 20 the ram 21 the driving voltage output circuit 23 and the voltage detection circuit 22 are connected to the cpu 19 the voltage detection circuit 22 is connected to the positive terminal 9 and the negative terminal 10 the voltage detection circuit 22 measures the voltage v cc between the positive and negative terminals 9 and 10 and constantly sends the results of the measurements to the cpu 19 the switch 24 provided between positive terminal 9 and the voltage detection circuit 22 makes and breaks i e turns on and off the zinc air cell the cpu 19 continuously monitors the voltage between the terminals v cc according to the information transmitted from the voltage detection circuit 22 and stores the resulting voltage value in the ram 21 the cpu 19 determines the volume of the air to be sent from the piezo electric pump 8 to the air diffusion chamber 2 based on the deviation of the voltage between the terminals v cc stored in the ram 21 from the reference voltage v ref stored in the rom 20 the optimal voltage to be applied to the piezo electric ceramic panels 15 is also determined by the cpu 19 the cpu 19 transmits a control.