A projected capacitive detecting system comprises a sensing pad device and a monitoring module. The sensing pad device comprises at least one sensing array unit and at least one control unit. The at least one sensing array unit comprises multiple sensing electrodes arranged in an array. The at least one control unit is electrically connected to the multiple sensing electrodes to receive capacitances of the multiple sensing electrodes. The at least one control unit performs a capacitance conversion to convert the capacitances of the multiple sensing electrodes to obtain multiple capacitive sensing values and digitize the multiple capacitive sensing values to obtain Boolean true/false results. The monitoring module is electrically connected to the at least one control unit to receive and display the multiple capacitive sensing values and the Boolean true/false results as references for determining human activities.
