A golf club having a sensor that is removably connected at one or more positions of the golf club where the sensor comprises an inertial measurement unit including an accelerometer capable of measuring linear accelerations in three orthogonal axes and a gyroscope capable of measuring an angular rate of rotation around the same axes. The sensor may further comprise a processor which may perform instructions to detect the impact of the golf club with a golf ball and determine the start of the golf swing without any additional input from the user. The sensor may further have a power management system to extend the life of the power source.