A low frequency oscillator includes a plurality of drum-shaped oscillators. The plurality of CPUs are connected with the same system bus. The dose counter further includes an actuator mechanism having a first ratchet drive pawl for engaging the ratchet teeth of the first gear wheel in response to the dispensation of a medicament dose, and a second ratchet drive pawl for engaging the ratchet teeth of a gear wheel coupled to the display. A spring can also be used to urge the male member and the female member apart when the working fluid is at a relatively low pressure.