| 摘要 |
A system 100 for determining the velocity of a hammer 120 of a musical keyboard instrument comprises a light transceiver 140 and processing circuitry 160. The light transceiver 140 transmits a light signal, such as infrared illumination, to a hammer and receives a reflected light signal from the hammer indicative of the velocity of the hammer. An electrical signal is sent to the processing circuitry, where the electrical signal is based on the reflected light signal from the hammer. The processing circuitry receives and processes 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. The trigger points may be voltages stored in sample-and-hold devices and may represent different hammer heights. A third trigger point may be included, representing the hammer height when a damper of the keyboard is no longer in contact with a string. The hammer velocity calculations may be used to operate an automatic piano. Claims to a calibration module and method are also disclosed. |
