Turtle elevator

radar = peripheral.wrap("bottom")
on = {}

function add(number)
  -- print("add: " .. number)
  local cur = redstone.getBundledOutput("right")
  if not colors.test(cur, number) then
    redstone.setBundledOutput("right", cur + number)
  end

  on["" .. number] = 5
end

function remove(number)
  local cur = redstone.getBundledOutput("right")
  if colors.test(cur, number) then
    redstone.setBundledOutput("right", cur - number)
  end
end

function within(value, first, second)
  return first <= value and value <= second
end

function check()
  for k, v in pairs(on) do
    -- print(k .. ": " .. v)
    if v == 0 then
      remove(tonumber(k))
    else
      on[k] = on[k] - 1
    end
  end
end

while true do
  players = radar.getPlayers()
  for index, player in pairs(players) do
    -- print(player.x)
    -- print(player.y)
    -- print(player.z)
    if within(player.x, -1, 0) and within(player.y, 4, 7) and player.z == 0 then
      add(1)
    end
    if within(player.x, -1, 0) and within(player.y, 15, 18) and player.z == 0 then
      add(2)
    end
    if within(player.x, -1, 0) and within(player.y, 26, 29) and player.z == 0 then
      add(4)
    end
    if within(player.x, -1, 0) and within(player.y, 37, 40) and player.z == 0 then
      add(8)
    end
    if within(player.x, -1, 0) and within(player.y, 48, 51) and player.z == 0 then
      add(16)
    end
    if within(player.x, -1, 0) and within(player.y, 59, 62) and player.z == 0 then
      add(64)
    end
    if within(player.x, -1, 0) and within(player.y, 70, 73) and player.z == 0 then
      add(128)
    end
  end
  os.sleep(0.1)
  check()
end