Body fluid sampling device with capacitive sensor

A drug delivery system, comprising:

• a housing;
• a controllable driver positioned in the housing;
• a penetrating member configured to be coupled to the controllable driver and positioned in the housing;
• an actuator processor coupled to a human interface processor that is lower power and slower than the actuator processor, the human interface processor configured to be in a sleep mode and run intermittently to conserve power with the human interface processor controlling power to the actuator processor, the actuator processor coupled to the controllable driver, the actuator processor storing profiles in a memory, in response to a user inputting information for a lancing event the actuator processor selects a controllable driver profile from a set of alternative driver profiles, and in response to the actuator processor choosing a profile the actuator processor modulates a power from a power supply to the controllable driver through an amplifier;
• a receptacle configured to be coupled to the penetrating member for delivery or withdrawal of an agent or body fluid;
• and
• a finger position element coupled to a register read configured to determine a relative position of a finger by checking if a series of pre-defined capacitance thresholds have been exceeded, the finger position element configured to report information about the relative position of the finger relative to an ideal position using information given as a percentage of a capacitance measured for a correct finger position and provides an estimate of an actual finger distance, wherein a relative position of the finger can be reported on a user interface.