An electromagnetic (EM) sensor includes a front end module generating an EM signal using electromagnetic waves transmitted from an external source, a sensor memory storing a portion of a plurality of machine learning models used to recognize the EM signal, and a microcontroller unit for recognizing the external electronic device emitting the electromagnetic waves by inputting feature values extracted from the EM signal to the machine learning models. If the machine learning models stored in the sensor memory are not able to recognize the external device, the feature values may be transmitted to a main processor, and the main processor may compare the feature values to another set of machine learning models.