Examples

• Simple Counter
• Hello World
• Monitoring Chest & Furnace
• Stopwatch
• Flow Control

Simple Counter

Very simple example with output on the Controller menu.

init() code:

a = 1

loop() code:

a = a + 1
$print("a = ", a)

end

Hello World

"Hello world" example with output on the Display.

init() code:

a = Array("Hello", "world", "of", "Minetest")

$clear_screen("0669")

for i,text in a.next() do
    $display("0669", i+2, text)
end

Monitoring Chest & Furnace

More realistic example to output Pusher states on the Display

init() code:

DISPLAY = "1234"
min = 0

loop() code:

-- call code every 60 sec
if ticks % 60 == 0 then
  -- output time in minutes
  min = min + 1
  $display(DISPLAY, 1, min, " min")

  -- Cactus chest overrun
  sts = $get_status("1034") -- read pusher status
  if sts == "blocked" then $display(DISPLAY, 2, "Cactus full") end

  -- Tree chest overrun
  sts = $get_status("1089")  -- read pusher status
  if sts == "blocked" then $display(DISPLAY, 3, "Tree full") end

  -- Furnace fuel empty
  sts = $get_status("2895")  -- read pusher status
  if sts == "standby" then $display(DISPLAY, 4, "Furnace fuel") end
end

Stopwatch

Stopwatch with highscore list, stored on the Server. You need the following nodes:

• SaferLua Controller
• SaferLua Battery
• SaferLua Server
• SmartLine Display
• SmartLine Player Detector
• SmartLine Button/Switch

You have to configure the Button/Switch as "switch" and configure the number of the SaferLua Controller to "connect" the switch with the Controller. When you turn on the switch, the time and the player name are taken. When you turn off the switch again, the time is calculated and the times of the best three players are shown on the Display.

init() code:

-- node numbers
DISPLAY = "0669"
SWITCH = "0670"
DETECTOR = "0671"
SERVER = "0674"

$events(true)
$loopcycle(0)
$clear_screen(DISPLAY)

-- read highscore data from Server, if available
-- otherwise generate a new 'Store'
highscore = $server_read(SERVER, "highscore") or Store()

loop() code:

if event then
    if $get_input(SWITCH) == "on" then
        time = $get_ms_time()
        name = $playerdetector(DETECTOR)
        $display(DISPLAY, 1, "running")
    elseif $get_input(SWITCH) == "off" then
        $display(DISPLAY, 1, "stopped")
        time = $get_ms_time()  - time
        $display(DISPLAY, 2, "Time: ", time)
        -- store the best (smallest) time only
        time = math.min(highscore.get(name) or 999999, time)
        highscore.set(name, time)
        keys = highscore.keys("up")
        -- output the top three with name and time
        for i, name in keys.next() do
            if i == 4 then break end
            $display(DISPLAY, i+3, name, ": ", highscore.get(name) / 1000.0)
        end
        -- store results on the Server
        $server_write(SERVER, "highscore", highscore)
    end
end

Flow Control

The Autocrafter need one or more items depending on the recipe to craft the output. For example the rail recipe need 2 wood and 6 steel items to generate 18 rail items. This disproportion of items could lead to the situation that the Autocrafter inventory is full of wood but has no steel.

To prevent inventory overloads, the following "flow control" example can be used.
It reads the item counters of the Pushers to control the item flow.

Before it goes into operation, the Autocrafter are flushed and all counters are reset.

init() code:

--------------------------------------------------------------------------------
-- Item flow control to prevent autostarter overloads
-- 2018-07-22 - v1.0 - first draft
--------------------------------------------------------------------------------

-- tubelib numbers
IN_STEEL = "0761"
IN_WOOD = "0762"
OUT_RAIL = "0763"
AUTOCRAFTER = "0760"
DISPLAY = "0765"

-- states
FLUSHING = 0
RUNNING = 1
$loopcycle(10)

-- flush autocrafter
state = FLUSHING
$send_cmnd(IN_STEEL, "off")
$send_cmnd(IN_WOOD, "off")
$send_cmnd(OUT_RAIL, "on")
$send_cmnd(AUTOCRAFTER, "on")
$clear_screen(DISPLAY)

loop() code:

-- wait until autocrafter goes standby
if state == FLUSHING then
    $display(DISPLAY, 1, "flushing...")
    sts = $get_status(AUTOCRAFTER)
    if sts == "standby" then
        -- start the flow control
        state = RUNNING
        $send_cmnd(IN_STEEL, "on")
        $send_cmnd(IN_WOOD, "on")
        $clear_counter(IN_STEEL)
        $clear_counter(IN_WOOD)
        $clear_counter(OUT_RAIL)
        $display(DISPLAY, 1, "running...")
    end
end

-- monitor IN/OUT pushers
if state == RUNNING then
    cnt_steel = $get_counter(IN_STEEL)
    cnt_wood = $get_counter(IN_WOOD)
    cnt_rail = $get_counter(OUT_RAIL)

    $display(DISPLAY, 2, "steel: ", cnt_steel)
    $display(DISPLAY, 3, "wood: ", cnt_wood)
    $display(DISPLAY, 4, "rails: ", cnt_rail)

    -- add some offset for rails + material in the autocrafter
    cnt_rail = cnt_rail + 50

    -- 6 steel + 2 wood gives 18 rails
    if cnt_steel/6 > cnt_rail/18 then
        $send_cmnd(IN_STEEL, "off")
        $display(DISPLAY, 6, "steel: ", "off")
    else
        $send_cmnd(IN_STEEL, "on")
        $display(DISPLAY, 6, "steel: ", "on")
    end

    if cnt_wood/2 > cnt_rail/18 then
        $send_cmnd(IN_WOOD, "off")
        $display(DISPLAY, 7, "wood: ", "off")
    else
        $send_cmnd(IN_WOOD, "on")
        $display(DISPLAY, 7, "wood: ", "on")
    end
end