| 摘要 |
Automatic tuning control arrangement for a string musical instrument, such as a guitar, has a pivoted tone arm with a hook at one end for attaching to an associated one of the guitar strings, and a shape memory metal wire tension motor extending between the tone arm and an anchor point on the instrument to rock the tone arm in opposition to the tension of the musical string. A strain sensor, such as a strain gauge, is mounted on the tone arm and it is electrically coupled to a control circuit that supplies a control current to the shape memory metal wire in the traction motor. A biasing spring can also be coupled between the tone arm and a bias anchor on the instrument to apply a spring bias in opposition to the musical string tension. As the guitar string or other string stretches over time, the traction motor will rock the tone arm to take up the slack and maintain an even tension on the string, thus keeping the string in tune. On the other hand, the shape memory metal alloy prevents resonance from occurring in the tone arm or biased spring, so that the musical notes played on the instrument maintain their original crispness and richness.
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