A sensing apparatus for sensing a posture change of a users body, comprising a base layer (10) and a plurality of sensors (A4, B4, C4, D4) disposed on the base layer (10) for giving a physiological function signal. The plurality of sensors are connected to form a circuit with two output terminals (91, 98) configured to output a sum circuit output value that varies with a force applied on one or more different sensors. Each of the plurality of sensors has a unique sensor output value that is different for each sensor. The sum circuit output value is the sum of the unique sensor output values, and the sum circuit output value of any combination of one or more sensor output values is different from the sum circuit output value of any other combination of one or more sensor output values.
