the present invention comprises a cardiopulmonary resuscitation feedback device and a method for performing cpr . a chest compression detector device is provided that measures chest compression during the administration of cpr . the chest compression detector device comprises a signal transmitter operably positioned on the chest of the patient and adapted to broadcast a signal , and a signal receiver adapted to receive the signal . the chest compression detector device also comprises a processor , operably connected to the signal transmitter and the signal receiver . the processor repeatedly analyzes the signal received to determine from the signal a series of measurements of compression of the chest , and feedback is provided to the rescuer based on the series of measurements .