A new tweak, called Piano Passcode, is now available in Cydia. This new tweak allows you to unlock your iOS device with beautiful music. Once you install the Piano Passcode tweak, your device will no longer require a 4-digit passcode. Instead you will be presented with a paino keyboard and all you have to do is press the keys ( configured by you ) to play some music and unlock your device.

Piano Passcode is available in Cydia Store via BigBoss repo for $0.99.

Source [FSM]