How to have one voice in multiple staves with lilypond?

Question

I want to produce a score with two staves (one with treble key, one with bass key, like a piano staff) and with a single voice navigating between the two staves. If the note is lower than the middle C, then it should be displayed in the bass staff, and if it is higher, then in the treble staff.

Is there an easy way to do this automatically ?

Answer 1

Use /autochange:

\new PianoStaff <<
  \new Staff = "up" {
    \new Voice = "melOne" {
      \key g \major
      \autochange \relative c' {
        g8 b a c b d c e
        d8 r fis, g a2
      }
    }
  }
  \new Staff = "down" {
    \key g \major
    \clef bass
  }
>>

For more information, see http://www.lilypond.org/doc/v2.18/Documentation/notation/common-notation-for-keyboards#changing-staff-automatically