A system, for determining the velocity of a hammer of a keyboard instrument, with a light transceiver and processing circuitry. The light transceiver being configured to transmit a light signal to a hammer to measure a hammer velocity, receive a reflected light signal from the hammer indicative of the velocity of the hammer and send an electrical signal to the processing circuitry, where the electrical signal is based on the reflected light signal from the hammer. The processing circuitry being configured to receive and process the electrical signal so that a time interval between the electrical signal passing through a first trigger point and a second trigger point and the velocity of the hammer can be determined.