Systems and methods are described in which the location of a tap on the body of a handheld device is determined in real time using data streams from an embedded inertial measurement unit (IMU). Taps may be generated by striking the handheld device with an object (e.g., a finger), or by moving the handheld device in a manner that causes it to strike another object. IMU accelerometer, gyroscopic and/or orientation (relative to the magnetic and/or gravitational pull of the earth) measurements are examined for signatures that distinguish a tap at a location on the body of the device compared with signal characteristics produced by taps at other locations. Neural network and/or numerical methods may be used to perform such classifications. Tap locations, tap timing and tap attributes such as the magnitude of applied forces, device orientation, and the amplitude and directions of motions during and following a tap, may be used to control or modulate responses within the handheld device and/or actions within connected devices.