Sensors - Yamaha Disklavier MX100A Product Handbook

13. Sensors

Hybrid models include a variety of sensors that are used in detecting and recording performance actions. The
three main categories are Hammer Sensor, Key Sensor, and Pedal Sensor.
The Hammer Sensor and Key Sensor are optical-fiber type, and detect both speed and position. Operation is based
on optical beams and metal shutters; the sensors detect mechanical movement through various crucial points by
detecting the blockage and non-blockage of the beams by the shutters. The number of beams and the shape of the
shutter—and consequently the number of detection points—vary according the Disklavier model. Sensors are
identified by the number of beams and the number of points: "1-beam 2-points", "2-beams 4-points", "1-beam
continuos", and so on.
The Pedal Sensor also varies according to the model. Some models use an ON/OFF switch-type sensor, while oth-
ers use a grayscale-type sensor capable of measuring pedal position accurately up to the half-pedal point. The
PRO series uses a pulse-scale sensor that detects pedal displacement by counting of pulses.
The table below shows the sensor types used for each model.
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