Measuring heart activities (heartbeats) is critical for the early diagnosis of many killer diseases, such as hypertension, heart attacks, or strokes. However, the conventional methods and devices (e.g., Electrocardiograms) are still cumbersome for frequent usage. In this project, we will explore using our mobile phones, which are widely available nowadays, to capture heartbeats. There will be two main tasks: (1) implement the function on a mobile phone to capture audio signals from its microphone, (2) use this ability to capture heartbeats when pressing the phone's microphone on our Apical pulse point