Triggering sequence

A therapeutic substance delivery device includes a fluid path having a reservoir needle, a barrel needle, a barrel needle injection mechanism, and a pump assembly (a) configured to pump the substance from the reservoir to the subject, (b) shaped to define a pumping chamber, and (c) including a plunger disposed within the pumping chamber. The plunger moves back and forth through a plurality of discrete phases of motion. A first phase of movement of the plunger activates a first operation of a group of operations including (a) driving the reservoir needle into the reservoir, (b) advancing the body needle into the subject's body, (c) withdrawing the substance from the reservoir, (d) pumping the substance into the subject, and (e) retracting the body needle. A second phase of movement of the piston activates a second operation of the operating group. Other applications are also described. (Automatic translation with Google Translate, without legal value)