A system and method comprises structure for receiving in a handheld device biometric or environmental data from the vicinity of the handheld device. The system may include a handheld mobile device such as a cellular telephone, or that device and a separate mechanical housing configured be held in a hand of a user and to clamp to or contain the handheld device. The system may include a specialized radar unit and be designed to analyze radar signals to provide a signal indicative of time varying arterial blood pressure. The mechanical housing may include a receiver designed to receive a biometric or environmental signal and to wirelessly transmit a corresponding signal to the handheld device when clamped to the handheld device.
