Device and method for determining the fill level of a flexible medicine reservoir

1. A device for determining a fill level of an inflow-less flexible medicine reservoir as a source for medicine, the inflow-less flexible medicine reservoir having a monotonically decreasing fill level, comprising:

a stop surface designed and arranged such that the stop surface contacts the inflow-less flexible medicine reservoir while the inflow-less flexible medicine reservoir is filled above a predetermined level;

a release detector that generates an output signal indicative of contact between the stop surface and the inflow-less flexible medicine reservoir being released; and

a processing unit that determines the fill level of the inflow-less flexible medicine reservoir from an output signal of the release detector, wherein the processing unit takes into account information on an amount of medicine pumped from the inflow-less flexible medicine reservoir by a pump.

2. The device of claim 1 , wherein the release detector is a capacitive sensor that includes a plurality of electrodes.

3. The device of claim 2 , wherein at least one of the plurality of electrodes includes at least one of the following: a plurality of fingers and a meandering conductor, and wherein the plurality of electrodes are intertwined.

4. The device of claim 1 , wherein the release detector includes at least one of the following: a pressure sensor and a force sensor.

5. The device of claim 1 , wherein the release detector includes an optical detector.

6. The device of claim 1 , wherein the release detector includes a switch.

7. The device of claim 1 , wherein the stop surface is located on a ram that pushes against the inflow-less flexible medicine reservoir as long as the inflow-less flexible medicine reservoir is filled above the predetermined level.

8. The device of claim 1 , wherein the stop surface is a part of a housing that houses the inflow-less flexible medicine reservoir.

9. The device of claim 1 , comprising a plurality of release detectors.

10. The device of claim 1 , wherein the processing unit determines whether the fill level has fallen to or below a threshold.

11. The device of claim 1 , wherein the processing unit determines the fill level of the inflow-less flexible medicine reservoir.

12. A method for calculating a fill level of an inflow-less flexible medicine reservoir as a source for medicine, the inflow-less flexible medicine reservoir having a monotonically decreasing fill level, comprising:

determining by a processing unit when a threshold fill level of the inflow-less flexible medicine reservoir has been reached based on an output signal of a release detector indicative of contact between a stop surface and the inflow-less flexible medicine reservoir being released, wherein the stop surface is designed and arranged such that the stop surface contacts the inflow-less flexible medicine reservoir while the inflow-less flexible medicine reservoir is filled above a predetermined level;

determining an amount of medicine taken from the inflow-less flexible medicine reservoir since the threshold fill level has been reached by the processing unit taking into account information on an amount of medicine pumped from the inflow-less flexible medicine reservoir;

calculating the fill level by the processing unit subtracting the amount of medicine taken from the inflow-less flexible medicine reservoir from the threshold fill level; and

providing by the processing unit a fill level signal related the fill level.