FloorSwitcher

modem = peripheral.wrap("left")
modem.open(15)

local f = fs.open("loc.lua", "r")
loc = tonumber(f.readLine())
f.close()

turtle.select(1)
current = (turtle.getItemCount() > 0 and "2") or "1"

function switch(new)
  for i = 1, 4 do
    turtle.select(1)
    turtle.digUp()
    turtle.select(new)
    turtle.placeUp()
    turtle.forward()
    turtle.turnRight()
  end
end

while true do
  e, _, _, _, message = os.pullEvent("modem_message")
  new = message:sub(loc, loc)
  if new ~= current then
    switch(tonumber(new))
    current = new
  end
end