data-piano
Map numeric data to MIDI keyboard keys (where key 60 is Middle C)
Created primarily for use with baudio, but should work for other sound synthesis projects
Reference
Wikipedia article on piano key frequencies (note that this uses a standard 88-key piano rather than a MIDI keyboard)
Dominique Vandennucker's MIDI tutorial for programmers
Example
var DataPiano = require('data-piano')
var baudio = require('baudio')
var data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
var piano = new DataPiano({
data: data,
velocityData: data,
lowKey: 60,
highKey: 71,
lowVelocity: 42,
highVelocity: 80,
stopVelocity: 80
})
console.log(piano.keys)
console.log(piano.freqs)
console.log(piano.velocities)
var playFunc = piano.getSinPlayFunc(2)
var b = baudio(playFunc)
b.play()
var firstBeat = piano.getMidiPlayFunc(0)(0)
console.log(firstBeat)
Defaults
{
data: undefined,
velocityData: undefined,
lowKey: 60,
highKey: 71,
lowVelocity: 0,
highVelocity: 127,
stopVelocity: (lowVelocity+highVelocity)/2
}
API
###var DataPiano = require('data-piano')
Main class for data-piano
###DataPiano.keyToFreq(key)
###DataPiano#keyToFreq(key)
Utility function that returns the corresponding frequency for a given piano key. Can be used as either a static or instance method.
###DataPiano#getSinPlayFunc(bps)
Returns a function of time that represents the data played in sequence as sine waves, changing to the next key bps
times per second
###DataPiano#getSquarePlayFunc(bps)
Returns a function of time that represents the data played in sequence as square waves, changing to the next key bps
times per second
###DataPiano#getSawtoothPlayFunc(bps)
Returns a function of time that represents the data played in sequence as sawtooth waves, changing to the next key bps
times per second
###DataPiano#getMidiPlayFunc(channel)
Returns a function of beat # that represents the midi instruction to play the data in sequence, changing to the next key on each beat of the midi clock
###DataPiano#getMidiStopFunc(channel)
Returns a function of beat # that represents the midi instruction to turn off the note from the previous beat, an instruction that must be passed every time you want to change to a new note
###DataPiano#read/DataPiano#pipe
DataPiano instances are also readable streams, and will output a looping bytestream of midi messages that will turn on and off beat notes in sequence. It is up to the consumer to provide timing and midi port interfacing.