Abstract: A therapeutic substance delivery apparatus includes a housing, a reservoir for holding a therapeutic substance disposed at least partially within the housing, a position sensor having at least three states, a plunger which is slidable within the reservoir, and a plunger-sensor engagement interface coupled to the plunger within the reservoir and extending from within the reservoir to outside of the reservoir. The plunger and the position sensor are arranged such that the plunger-sensor engagement interface causes the position sensor to change states as the plunger slides within the reservoir. Control circuitry identifies a new state indication of the apparatus based on (a) a change in state of the position sensor, or (b) a previous or current state of the apparatus in combination with a threshold amount of time having elapsed without the position sensor changing state. Other applications are also described.

Abstract: A therapeutic substance delivery device includes a fluid path having a reservoir needle, a body needle, a body needle injection mechanism, and a pumping assembly (a) configured to pump the substance from the reservoir to the subject, (b) shaped to define a pump chamber, and (c) including a plunger disposed within the pump chamber. The plunger moves back and forth through a plurality of discrete motion phases. A first motion phase of the plunger actuates a first operation from a group of operations including (a) driving the reservoir needle to penetrate the reservoir, (b) advancing the body needle into the body of the subject, (c) withdrawing the substance from the reservoir, (d) pumping the substance into the subject, and (e) retracting the body needle. A second motion phase of the plunger actuates a second operation from the group of operations. Other applications are also described.

Abstract: A therapeutic substance delivery device includes a fluid path having a reservoir needle, a body needle, a body needle injection mechanism, and a pumping assembly (a) configured to pump the substance from the reservoir to the subject, (b) shaped to define a pump chamber, and (c) including a plunger disposed within the pump chamber. The plunger moves back and forth through a plurality of discrete motion phases. A first motion phase of the plunger actuates a first operation from a group of operations including (a) driving the reservoir needle to penetrate the reservoir, (b) advancing the body needle into the body of the subject, (c) withdrawing the substance from the reservoir, (d) pumping the substance into the subject, and (e) retracting the body needle. A second motion phase of the plunger actuates a second operation from the group of operations. Other applications are also described.