The present invention provides a CPR sensor that includes a thin and substantially flat flexible substrate having one or more sensor arrays, a POWER source, an output interface and a processor or analog circuit and all of which are disposed ON the substantially flat flexible substrate. The substrate can be any shape (e.g., rectangular, circular, a polygon and an irregular shape that is decorative) and made from a polymer and metal film or other suitable material. Note that the substrate can be rigid or semi-flexible instead of flexible. A protective layer may cover the sensor array, the POWER source and the processor or analog circuit. Alternatively and a protective covering can be used to encapsulate the device. The one or more sensor arrays measure one or more of the following compressions characteristics: compression depth, compression force and compression frequency and compression acceleration.
