Dispensing Fluid from an Infusion Pump System

A portable and wearable infusion pump system, comprising:

• a portable housing defining a space to receive a medicine;
• a pump drive system positioned within the portable housing so as to dispense medicine from the portable housing when the medicine is received in the space;
• and
• control circuitry that electrically communicates with the pump drive system via an electrical connection with the pump drive system to control dispensation of the medicine from the portable housing when the medicine is received in the space, the control circuitry being electrically connected to a user interface that is configured to received user input related to dispensing the medicine and that is configured to display information related to dispensing the medicine,
• wherein pump drive system positioned within the portable housing comprises:
• a battery-powered motor to rotate one or more full rotations in response to one or more electrical signals communicated from the control circuitry via the electrical connection;
• a piston rod movable to dispense a portion of the medicine from the portable housing;
• and a mechanism to advance the piston rod toward the medicine housed in the portable housing, the mechanism comprising a pawl and a ratchet member, the pawl positioned to engage one or more teeth of the ratchet member, wherein the pawl is adjustable between a first position and a second position to move the ratchet member in a forward direction so as to cause the piston rod to advance toward the medicine, wherein the one or more full rotations of the battery-powered motor cause the pawl to adjust toward one of the first position or the second position.