A system may include a sensor system and a control system configured for communication with the sensor system. The sensor system may include an ultrasonic sensor system. The control system may be capable of determining, based at least in part on signals from the ultrasonic sensor system, whether a personal medical device is within a predetermined distance from the mobile device. The control system may be capable of adjusting one or more mobile device settings in response to a determination that the personal medical device is within the predetermined distance of the mobile device.