note = nil
noteSide = nil
for i, side in pairs(rs.getSides()) do
  if peripheral.getType(side) == "note" then
    note = peripheral.wrap(side)
    noteSide = side
    break
  end
end

if note == nil then
  print("No Note peripheral found")
  return
end

print("Using Note peripheral on "..noteSide)
print("Press any key to stop")

parallel.waitForAny(
  function()
    while true do
      note.playNote(math.random(0, 4), math.random(0, 24))
      sleep(0.25)
    end
  end,
  function()
    os.pullEvent("char")
  end
)