The Yamaha FC-3A is about as close as you can get to the feel and response of the sustain pedal on an acoustic piano. Users are able to use half-pedalling functions and access the expressive responsiveness of what they would have on an acoustic piano.
Yamaha FC-3A Foot Pedal
A foot pedal for use with digital pianos, keyboards, synthesizers, and stage pianos. This pedal is compatible with half-pedaling functions, allowing detailed, expressive performance.