Resistive and capacitive force sensor and method of operating the same

A resistive and capacitive force sensor, the force sensor comprising:

• at least one sensor element having at least a first electrode E1 and a second electrode E2, wherein the sensor element is designed in such a way that, when an external force F is applied, an inherent electrical capacitance C of the first electrode E1 and/or the second electrode E2 and an electrical resistance R between the first electrode E1 and the second electrode E2 change as a function of a magnitude |F| of the force F;
• a first measuring unit electrically connected to the first electrode E1 and the second electrode E2, the first measuring unit designed and arranged to determine a time-dependent intrinsic electrical capacitance C(t) of the electrode E2;
• a second measuring unit electrically connected to the first electrode E1 and the second electrode E2, the second measuring unit designed and arranged for to determine a time-dependent electrical resistance R(t) between the first electrode E1 and the second electrode E2;
• an evaluation unit designed and arranged to determine a magnitude |F(t)| of a force F(t) applied externally to the sensor element (100) as a function of a mean value mean (C [t-Δt, t]) of the determined time-dependent intrinsic electrical capacitance C(t) in a time interval [t-Δt, t] and as a function of a mean value mean (R [t-Δt, t]) of the determined time-dependent electrical resistance R(t) in the time interval [t-Δt, t]:
• (1) |F(t)|=|F (mean (C [t-Δt, t]), mean (R [t-Δt, t])) |, with Δt:
• time period and t:
• time;
• and
• an output unit to output and/or display the determined magnitude |F(t)| of the force F(t).