An electronic assembly includes a casing to conduct electricity flowing between at least some electronic components disposed within the casing. The electronic components include an ultrasonic transducer coupled to emit ultrasonic signals, and a battery to provide the electricity. A controller is coupled to the ultrasonic transducer and the battery, and the controller includes logic that when executed by the controller causes the electronic assembly to perform operations, including: instructing the ultrasonic transducer to emit the ultrasonic signals.