ApneaApp Sonar Graphic (IMAGE) University of Washington Caption ApneaApp uses a smartphone's speaker and microphone to emit and receive inaudible sound waves, which is similar to how bats navigate. Credit University of Washington Usage Restrictions With credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.