diff --git a/init.lua b/init.lua
index 96f0d86..fb1b2ac 100644
--- a/init.lua
+++ b/init.lua
@@ -227,6 +227,7 @@ else
 --	dofile(MP.."/lua_controller/controller.lua")
 --	dofile(MP.."/lua_controller/commands.lua")
 --	dofile(MP.."/lua_controller/server.lua")
+--	dofile(MP.."/lua_controller/sensorchest.lua")
 	
 	-- Items
 	dofile(MP.."/items/barrel.lua")
diff --git a/lua_controller/commands.lua b/lua_controller/commands.lua
new file mode 100644
index 0000000..315c4f2
--- /dev/null
+++ b/lua_controller/commands.lua
@@ -0,0 +1,235 @@
+--[[
+
+	sl_controller
+	=============
+
+	Copyright (C) 2018 Joachim Stolberg
+
+	LGPLv2.1+
+	See LICENSE.txt for more information
+
+	commands.lua:
+	
+	Register all basic controller commands
+
+]]--
+
+-- store protection data locally
+local LocalRef = {}
+local function not_protected(owner, numbers)
+	LocalRef[owner] = LocalRef[owner] or {}
+	if LocalRef[owner][numbers] == nil then
+		LocalRef[owner][numbers] = techage.check_numbers(numbers, owner)
+	end
+	return LocalRef[owner][numbers]
+end
+
+techage.lua_ctlr.register_function("get_input", {
+	cmnd = function(self, num)
+		num = tostring(num or "")
+		return techage.lua_ctlr.get_input(self.meta.number, num)
+	end,
+	help = ' $get_input(num)  --> "on", "off", or nil\n'..
+		' Read local input value from device with number "num".\n'..
+		' example: inp = $get_input("1234")\n'..
+		" The device has to be connected with the controller."
+})
+
+techage.lua_ctlr.register_function("get_status", {
+	cmnd = function(self, num) 
+		num = tostring(num or "")
+		return techage.send_single(self.meta.number, num, "state", nil)
+	end,
+	help = " $get_status(num) ,\n"..
+		" Read status string from a remote device.\n"..
+		' example: sts = $get_status("1234")'
+})
+
+techage.lua_ctlr.register_function("get_player_action", {
+	cmnd = function(self, num) 
+		num = tostring(num or "")
+		return unpack(techage.send_single(self.meta.number, num, "player_action", nil) or {"","",""})
+	end,
+	help = " $get_player_action(num) ,\n"..
+		" Read player action status from a Sensor Chest.\n"..
+		' example: player, action, item = $get_player_action("1234")'
+})
+
+--techage.lua_ctlr.register_function("get_counter", {
+--	cmnd = function(self, num) 
+--		num = tostring(num or "")
+--		return techage.send_single(self.meta.number, num, "counter", nil)
+--	end,
+--	help = " $get_counter(num)\n"..
+--		" Read number of pushed items from a\n"..
+--		" Pusher/Distributor node.\n"..
+--		" The Pusher returns a single value (number)\n"..
+--		" The Distributor returns a list with 4 values\n"..
+--		" like: {red=1, green=0, blue=8, yellow=0}\n"..
+--		' example: cnt = $get_counter("1234")\n'
+--})
+
+--techage.lua_ctlr.register_function("clear_counter", {
+--	cmnd = function(self, num) 
+--		num = tostring(num or "")
+--		return techage.send_single(self.meta.number, num, "clear_counter", nil)
+--	end,
+--	help = " $clear_counter(num)\n"..
+--		" Set counter(s) from Pusher/Distributor to zero.\n"..
+--		' example: $clear_counter("1234")'
+--})
+
+techage.lua_ctlr.register_function("get_fuel_value", {
+	cmnd = function(self, num) 
+		num = tostring(num or "")
+		return techage.send_single(self.meta.number, num, "fuel", nil)
+	end,
+	help = " $get_fuel_value(num)\n"..
+		" Read fuel value from fuel consuming blocks.\n"..
+		' example: val = $get_fuel_value("1234")'
+})
+
+--techage.lua_ctlr.register_function("get_num_items", {
+--	cmnd = function(self, num, idx) 
+--		num = tostring(num or "")
+--		idx = tonumber(idx)
+--		return techage.send_single(self.meta.number, num, "num_items", idx)
+--	end,
+--	help = " $get_num_items(num)\n"..
+--		" Read number of stored items in one\n"..
+--		" storage (1..8) from a Warehouse Box.\n"..
+--		' example: cnt = $get_num_items("1234", 4)\n'
+--})
+
+techage.lua_ctlr.register_function("time_as_str", {
+	cmnd = function(self) 
+		local t = minetest.get_timeofday()
+		local h = math.floor(t*24) % 24
+		local m = math.floor(t*1440) % 60
+		return string.format("%02d:%02d", h, m)
+	end,
+	help = " $time_as_str()  --> e.g. '18:45'\n"..
+		" Read time of day as string (24h).\n"..
+		' example: time = $time_as_str()'
+})
+
+techage.lua_ctlr.register_function("time_as_num", {
+	cmnd = function(self, num) 
+		local t = minetest.get_timeofday()
+		local h = math.floor(t*24) % 24
+		local m = math.floor(t*1440) % 60
+		return h * 100 + m
+	end,
+	help = " $time_as_num()  --> e.g.: 1845\n"..
+		" Read time of day as number (24h).\n"..
+		' example: time = $time_as_num()'
+})
+
+techage.lua_ctlr.register_function("playerdetector", {
+	cmnd = function(self, num) 
+		num = tostring(num or "")
+		if not_protected(self.meta.owner, num) then
+			return techage.send_single(self.meta.number, num, "name", nil)
+		end
+	end,
+	help = ' $playerdetector(num) --> e.g. "Joe"\n'..
+		' "" is returned if no player is nearby.\n'..
+		' example: name = $playerdetector("1234")'
+})
+
+techage.lua_ctlr.register_action("send_cmnd", {
+	cmnd = function(self, num, text) 
+		num = tostring(num or "")
+		text = tostring(text or "")
+		if not_protected(self.meta.owner, num) then
+			techage.send_single(self.meta.number, num, text, nil)
+		end
+	end,
+	help = " $send_cmnd(num, text)\n"..
+		' Send a command to the device with number "num".\n'..
+		' example: $send_cmnd("1234", "on")'
+})
+
+techage.lua_ctlr.register_action("set_filter", {
+	cmnd = function(self, num, slot, val) 
+		num = tostring(num or "")
+		slot = tostring(slot or "red")
+		val = tostring(val or "on")
+		if not_protected(self.meta.owner, num) then
+			techage.send_single(self.meta.number, num, "filter", {slot=slot, val=val})
+		end
+	end,
+	help = " $set_filter(num, slot, val)\n"..
+		' Turn on/off a Distributor filter slot.\n'..
+		' example: $set_filter("1234", "red", "off")'
+})
+
+
+techage.lua_ctlr.register_action("display", {
+	cmnd = function(self, num, row, text1, text2, text3)
+		num = tostring(num or "")
+		text1 = tostring(text1 or "")
+		text2 = tostring(text2 or "")
+		text3 = tostring(text3 or "")
+		if not_protected(self.meta.owner, num) then
+			techage.send_single(self.meta.number, num, "set", {row = row, str = text1..text2..text3})
+		end
+	end,
+	help = " $display(num, row, text,...)\n"..
+		' Send a text line to the display with number "num".\n'..
+		" 'row' is a value from 1..5\n"..
+		" The function accepts up to 3 text parameters\n"..
+		' example: $display("0123", 1, "Hello ", name, " !")'
+})
+
+techage.lua_ctlr.register_action("clear_screen", {
+	cmnd = function(self, num) 
+		num = tostring(num or "")
+		if not_protected(self.meta.owner, num) then
+			techage.send_single(self.meta.number, num, "clear", nil)
+		end
+	end,
+	help = " $clear_screen(num)\n"..
+		' Clear the screen of the display\n'..
+		' with number "num".\n'..
+		' example: $clear_screen("1234")'
+})
+
+techage.lua_ctlr.register_action("chat", {
+	cmnd = function(self, text1, text2, text3) 
+		text1 = tostring(text1 or "")
+		text2 = tostring(text2 or "")
+		text3 = tostring(text3 or "")
+		minetest.chat_send_player(self.meta.owner, "[TA4 Lua Controller] "..text1..text2..text3)
+	end,
+	help =  " $chat(text,...)\n"..
+		" Send yourself a chat message.\n"..
+		" The function accepts up to 3 text parameters\n"..
+		' example: $chat("Hello ", name)'
+})
+
+techage.lua_ctlr.register_action("door", {
+	cmnd = function(self, pos, text) 
+		pos = tostring(pos or "")
+		text = tostring(text or "")
+		pos = minetest.string_to_pos("("..pos..")")
+		if pos then
+			local door = doors.get(pos)
+			if door then
+				local player = {
+					get_player_name = function() return self.meta.owner end,
+					is_player = function() return true end,
+				}
+				if text == "open" then
+					door:open(player)
+				elseif text == "close" then
+					door:close(player)
+				end
+			end
+		end
+	end,
+	help =  " $door(pos, text)\n"..
+		' Open/Close a door at position "pos"\n'..
+		' example: $door("123,7,-1200", "close")\n'..
+		" Hint: Use the Techage Programmer to\ndetermine the door position."
+})
diff --git a/lua_controller/controller.lua b/lua_controller/controller.lua
new file mode 100644
index 0000000..369e793
--- /dev/null
+++ b/lua_controller/controller.lua
@@ -0,0 +1,617 @@
+--[[
+
+	TechAge
+	=======
+
+	Copyright (C) 2019-2020 Joachim Stolberg
+
+	GPL v3
+	See LICENSE.txt for more information
+	
+	Lua Controller
+
+]]--
+
+-- for lazy programmers
+local S = function(pos) if pos then return minetest.pos_to_string(pos) end end
+local M = minetest.get_meta
+
+local sHELP = [[TA4 Lua Controller
+
+ This controller is used to control and monitor 
+ TechAge machines.
+ This controller can be programmed in Lua.
+ 
+ See on GitHub for more help: goo.gl/Et8D6n
+
+ The controller only runs, if a battery is 
+ placed nearby.
+ 
+]]
+
+techage.lua_ctlr = {}
+
+local BATTERY_CAPA = 5000000
+
+local Cache = {}
+
+local STATE_STOPPED = 0
+local STATE_RUNNING = 1
+
+local tCommands = {}
+local tFunctions = {" Overview", " Data structures"}
+local tHelpTexts = {[" Overview"] = sHELP, [" Data structures"] = safer_lua.DataStructHelp}
+local sFunctionList = ""
+local tFunctionIndex = {}
+
+minetest.after(2, function() 
+	sFunctionList = table.concat(tFunctions, ",") 
+	for idx,key in ipairs(tFunctions) do
+		tFunctionIndex[key] = idx
+	end
+end)
+
+local function output(pos, text)
+	local meta = minetest.get_meta(pos)
+	text = meta:get_string("output") .. "\n" .. (text or "")
+	text = text:sub(-500,-1)
+	meta:set_string("output", text)
+end
+
+--
+-- API functions for function/action registrations
+--
+function techage.lua_ctlr.register_function(key, attr)
+	tCommands[key] = attr.cmnd
+	table.insert(tFunctions, " $"..key)
+	tHelpTexts[" $"..key] = attr.help
+end
+
+function techage.lua_ctlr.register_action(key, attr)
+	tCommands[key] = attr.cmnd
+	table.insert(tFunctions, " $"..key)
+	tHelpTexts[" $"..key] = attr.help
+end
+
+local function merge(dest, keys, values)
+  for idx,key in ipairs(keys) do
+    dest.env[key] = values[idx]
+  end
+  return dest
+end
+
+techage.lua_ctlr.register_action("print", {
+	cmnd = function(self, text1, text2, text3)
+		local pos = self.meta.pos
+		text1 = tostring(text1 or "")
+		text2 = tostring(text2 or "")
+		text3 = tostring(text3 or "")
+		output(pos, text1..text2..text3)
+	end,
+	help = " $print(text,...)\n"..
+		" Send a text line to the output window.\n"..
+		" The function accepts up to 3 text strings\n"..
+		' e.g. $print("Hello ", name, " !")'
+})
+
+techage.lua_ctlr.register_action("loopcycle", {
+	cmnd = function(self, cycletime)
+		cycletime = math.floor(tonumber(cycletime) or 0)
+		local meta = minetest.get_meta(self.meta.pos)
+		meta:set_int("cycletime", cycletime)
+		meta:set_int("cyclecount", 0)
+	end,
+	help = "$loopcycle(seconds)\n"..
+		" This function allows to change the\n"..
+		" call frequency of the loop() function.\n"..
+		" value is in seconds, 0 = disable\n"..
+		' e.g. $loopcycle(10)'
+})
+
+techage.lua_ctlr.register_action("events", {
+	cmnd = function(self, event)
+		self.meta.events = event or false
+	end,
+	help = "$events(true/false)\n"..
+		" Enable/disable event handling.\n"..
+		' e.g. $events(true) -- enable events'
+})
+
+techage.lua_ctlr.register_function("get_ms_time", {
+	cmnd = function(self)
+		return math.floor(minetest.get_us_time() / 1000)
+	end,
+	help = "$get_ms_time()\n"..
+		" returns time with millisecond precision."
+})
+
+techage.lua_ctlr.register_function("position", {
+	cmnd = function(self, number)
+		local info = techage.get_node_info(number)
+		if info then
+			return S(info.pos)
+		end
+		return "(-,-,-)"
+	end,
+	help = "$position(number)\n"..
+		" returns the position '(x,y,z)' of the device\n with given number."
+})
+
+techage.lua_ctlr.register_action("battery", {
+	cmnd = function(self)
+		local meta = minetest.get_meta(self.meta.pos)
+		local batpos = minetest.string_to_pos(meta:get_string("battery"))
+		local batmeta = minetest.get_meta(batpos)
+		local val = (BATTERY_CAPA - math.min(batmeta:get_int("content") or 0, BATTERY_CAPA))
+		return 100 - math.floor((val * 100.0 / BATTERY_CAPA))
+	end,
+	help =  " $battery()\n"..
+		" Get charge level of battery connected to Controller.\n"..
+		" Function returns percent number (0-100) where 100 means full.\n"..
+		" example: battery_percent = $battery()"
+})
+
+
+local function formspec0(meta)
+	local state = meta:get_int("state") == techage.RUNNING
+	local init = meta:get_string("init")
+	init = minetest.formspec_escape(init)
+	return "size[4,3]"..
+	default.gui_bg..
+	default.gui_bg_img..
+	default.gui_slots..
+	"label[0,0;No Battery?]"..
+	"button[1,2;1.8,1;start;Start]"
+end
+
+local function formspec1(meta)
+	local state = meta:get_int("state") == techage.RUNNING
+	local cmnd = state and "stop;Stop" or "start;Start"
+	local init = meta:get_string("init")
+	init = minetest.formspec_escape(init)
+	return "size[10,8]"..
+	default.gui_bg..
+	default.gui_bg_img..
+	default.gui_slots..
+	"tabheader[0,0;tab;init,func,loop,outp,notes,help;1;;true]"..
+	"textarea[0.3,0.2;10,8.3;init;function init();"..init.."]"..
+	"label[0,7.3;end]"..
+	"button_exit[4.4,7.5;1.8,1;cancel;Cancel]"..
+	"button[6.3,7.5;1.8,1;save;Save]"..
+	"button[8.2,7.5;1.8,1;"..cmnd.."]"
+end
+
+local function formspec2(meta)
+	local state = meta:get_int("state") == techage.RUNNING
+	local cmnd = state and "stop;Stop" or "start;Start"
+	local func = meta:get_string("func")
+	func = minetest.formspec_escape(func)
+	return "size[10,8]"..
+	default.gui_bg..
+	default.gui_bg_img..
+	default.gui_slots..
+	"tabheader[0,0;tab;init,func,loop,outp,notes,help;2;;true]"..
+	"textarea[0.3,0.2;10,8.3;func;functions:;"..func.."]"..
+	"button_exit[4.4,7.5;1.8,1;cancel;Cancel]"..
+	"button[6.3,7.5;1.8,1;save;Save]"..
+	"button[8.2,7.5;1.8,1;"..cmnd.."]"
+end
+
+local function formspec3(meta)
+	local state = meta:get_int("state") == techage.RUNNING
+	local cmnd = state and "stop;Stop" or "start;Start"
+	local loop = meta:get_string("loop")
+	loop = minetest.formspec_escape(loop)
+	return "size[10,8]"..
+	default.gui_bg..
+	default.gui_bg_img..
+	default.gui_slots..
+	"tabheader[0,0;tab;init,func,loop,outp,notes,help;3;;true]"..
+	"textarea[0.3,0.2;10,8.3;loop;function loop(ticks, elapsed);"..loop.."]"..
+	"label[0,7.3;end]"..
+	"button_exit[4.4,7.5;1.8,1;cancel;Cancel]"..
+	"button[6.3,7.5;1.8,1;save;Save]"..
+	"button[8.2,7.5;1.8,1;"..cmnd.."]"
+end
+
+local function formspec4(meta)
+	local state = meta:get_int("state") == techage.RUNNING
+	local cmnd = state and "stop;Stop" or "start;Start"
+	local output = meta:get_string("output")
+	output = minetest.formspec_escape(output)
+	output = output:gsub("\n", ",")
+	return "size[10,8]"..
+	default.gui_bg..
+	default.gui_bg_img..
+	default.gui_slots..
+	"tabheader[0,0;tab;init,func,loop,outp,notes,help;4;;true]"..
+	"table[0.2,0.2;9.5,7;output;"..output..";200]"..
+	"button[4.4,7.5;1.8,1;clear;Clear]"..
+	"button[6.3,7.5;1.8,1;update;Update]"..
+	"button[8.2,7.5;1.8,1;"..cmnd.."]"
+end
+
+local function formspec5(meta)
+	local notes = meta:get_string("notes")
+	notes = minetest.formspec_escape(notes)
+	return "size[10,8]"..
+	default.gui_bg..
+	default.gui_bg_img..
+	default.gui_slots..
+	"tabheader[0,0;tab;init,func,loop,outp,notes,help;5;;true]"..
+	"textarea[0.3,0.2;10,8.3;notes;Notepad:;"..notes.."]"..
+	"button_exit[6.3,7.5;1.8,1;cancel;Cancel]"..
+	"button[8.2,7.5;1.8,1;save;Save]"
+end
+
+local function formspec6(items, pos, text)
+	text = minetest.formspec_escape(text)
+	return "size[10,8]"..
+	default.gui_bg..
+	default.gui_bg_img..
+	default.gui_slots..
+	"tabheader[0,0;tab;init,func,loop,outp,notes,help;6;;true]"..
+	"label[0,-0.2;Functions:]"..
+	"dropdown[0.3,0.2;10,8.3;functions;"..items..";"..pos.."]"..
+	"textarea[0.3,1.3;10,8;help;Help:;"..text.."]"
+end
+
+local function patch_error_string(err, line_offs)
+	local tbl = {}
+	for s in err:gmatch("[^\r\n]+") do
+		if s:find("loop:(%d+):") then
+			local prefix, line, err = s:match("(.-)loop:(%d+):(.+)")
+			if prefix and line and err then
+				if tonumber(line) < line_offs then
+					table.insert(tbl, prefix.."func:"..line..":"..err)
+				else
+					line = tonumber(line) - line_offs
+					table.insert(tbl, prefix.."loop:"..line..":"..err)
+				end
+			end
+		else
+			table.insert(tbl, s)
+		end
+	end    
+	return table.concat(tbl, "\n")
+end
+
+local function error(pos, err)
+	local meta = minetest.get_meta(pos)
+	local func = meta:get_string("func")
+	local _,line_offs = string.gsub(func, "\n", "\n")
+	line_offs = line_offs + 1
+	err = patch_error_string(err, line_offs)
+	output(pos, err)
+	local number = meta:get_string("number")
+	meta:set_string("infotext", "Controller "..number..": error")
+	meta:set_int("state", techage.STOPPED)
+	meta:set_int("running", STATE_STOPPED)
+	meta:set_string("formspec", formspec4(meta))
+	minetest.get_node_timer(pos):stop()
+	return false
+end
+
+local function compile(pos, meta, number)
+	local init = meta:get_string("init")
+	local func = meta:get_string("func")
+	local loop = meta:get_string("loop")
+	local owner = meta:get_string("owner")
+	local env = table.copy(tCommands)
+	env.meta = {pos=pos, owner=owner, number=number, error=error}
+	local code = safer_lua.init(pos, init, func.."\n"..loop, env, error)
+	
+	if code then
+		Cache[number] = {code=code, inputs={}, events=env.meta.events}
+		Cache[number].inputs.term = nil  -- terminal inputs
+		Cache[number].inputs.msg = {}  -- message queue
+		return true
+	end
+	return false
+end
+
+local function battery(pos)
+	local battery_pos = minetest.find_node_near(pos, 1, {"techage:ta4_battery"})
+	if battery_pos then
+		local meta = minetest.get_meta(pos)
+		meta:set_string("battery", minetest.pos_to_string(battery_pos))
+		return true
+	end
+	return false
+end	
+
+local function start_controller(pos)
+	local meta = minetest.get_meta(pos)
+	local number = meta:get_string("number")
+	if not battery(pos) then
+		meta:set_string("formspec", formspec0(meta))
+		return false
+	end
+	
+	meta:set_string("output", "<press update>")
+	meta:set_int("cycletime", 1)
+	meta:set_int("cyclecount", 0)
+	meta:set_int("cpu", 0)
+	
+	if compile(pos, meta, number) then
+		meta:set_int("state", techage.RUNNING)
+		meta:set_int("running", STATE_RUNNING)
+		minetest.get_node_timer(pos):start(1)
+		meta:set_string("formspec", formspec4(meta))
+		meta:set_string("infotext", "Controller "..number..": running")
+		return true
+	end
+	return false
+end
+
+local function stop_controller(pos)
+	local meta = minetest.get_meta(pos)
+	local number = meta:get_string("number")
+	meta:set_int("state", techage.STOPPED)
+	meta:set_int("running", STATE_STOPPED)
+	minetest.get_node_timer(pos):stop()
+	meta:set_string("infotext", "Controller "..number..": stopped")
+	meta:set_string("formspec", formspec3(meta))
+end
+
+local function no_battery(pos)
+	local meta = minetest.get_meta(pos)
+	local number = meta:get_string("number")
+	meta:set_int("state", techage.STOPPED)
+	meta:set_int("running", STATE_STOPPED)
+	minetest.get_node_timer(pos):stop()
+	meta:set_string("infotext", "Controller "..number..": No battery")
+	meta:set_string("formspec", formspec0(meta))
+end
+
+local function update_battery(meta, cpu)
+	local pos = minetest.string_to_pos(meta:get_string("battery"))
+	if pos then
+		meta = minetest.get_meta(pos)
+		local content = meta:get_int("content") - cpu
+		if content <= 0 then
+			meta:set_int("content", 0)
+			return false
+		end
+		meta:set_int("content", content)
+		return true
+	end
+end
+
+local function call_loop(pos, meta, elapsed)
+	local t = minetest.get_us_time()
+	local number = meta:get_string("number")
+	if Cache[number] or compile(pos, meta, number) then
+		local cpu = meta:get_int("cpu") or 0
+		local code = Cache[number].code
+		local res = safer_lua.run_loop(pos, elapsed, code, error)
+		if res then 
+			t = minetest.get_us_time() - t
+			cpu = math.floor(((cpu * 20) + t) / 21)
+			meta:set_int("cpu", cpu)
+			meta:set_string("infotext", "Controller "..number..": running ("..cpu.."us)")
+			if not update_battery(meta, cpu) then
+				no_battery(pos)
+				return false
+			end
+		end
+		-- further messages available?
+		if next(Cache[number].inputs["msg"]) then
+			minetest.after(1, call_loop, pos, meta, -1)
+		end
+		return res
+	end
+	return false
+end
+
+local function on_timer(pos, elapsed)
+	local meta = minetest.get_meta(pos)
+	-- considering cycle frequency
+	local cycletime = meta:get_int("cycletime") or 1
+	local cyclecount = (meta:get_int("cyclecount") or 0) + 1
+	if cycletime == 0 or cyclecount < cycletime then
+		meta:set_int("cyclecount", cyclecount)
+		return true
+	end
+	meta:set_int("cyclecount", 0)
+
+	return call_loop(pos, meta, elapsed)
+end
+
+local function on_receive_fields(pos, formname, fields, player)
+	if minetest.is_protected(pos, player:get_player_name()) then
+		return
+	end
+	local meta = minetest.get_meta(pos)
+	
+	--print(dump(fields))
+	if fields.cancel == nil then
+		if fields.init then
+			meta:set_string("init", fields.init)
+			meta:set_string("formspec", formspec1(meta))
+		elseif fields.func then
+			meta:set_string("func", fields.func)
+			meta:set_string("formspec", formspec2(meta))
+		elseif fields.loop then
+			meta:set_string("loop", fields.loop)
+			meta:set_string("formspec", formspec3(meta))
+		elseif fields.notes then
+			meta:set_string("notes", fields.notes)
+			meta:set_string("formspec", formspec5(meta))
+		end	
+	end
+	
+	if fields.update then
+		meta:set_string("formspec", formspec4(meta))
+	elseif fields.clear then
+		meta:set_string("output", "<press update>")
+		meta:set_string("formspec", formspec4(meta))
+	elseif fields.tab == "1" then
+		meta:set_string("formspec", formspec1(meta))
+	elseif fields.tab == "2" then
+		meta:set_string("formspec", formspec2(meta))
+	elseif fields.tab == "3" then
+		meta:set_string("formspec", formspec3(meta))
+	elseif fields.tab == "4" then
+		meta:set_string("formspec", formspec4(meta))
+	elseif fields.tab == "5" then
+		meta:set_string("formspec", formspec5(meta))
+	elseif fields.tab == "6" then
+		meta:set_string("formspec", formspec6(sFunctionList, 1, sHELP))
+	elseif fields.start == "Start" then
+		start_controller(pos)
+		minetest.log("action", player:get_player_name() ..
+			" starts the sl_controller at ".. minetest.pos_to_string(pos))
+	elseif fields.stop == "Stop" then
+		stop_controller(pos)
+	elseif fields.functions then
+		local key = fields.functions
+		local text = tHelpTexts[key] or ""
+		local pos = tFunctionIndex[key] or 1
+		meta:set_string("formspec", formspec6(sFunctionList, pos, text))
+	end
+end
+
+minetest.register_node("techage:ta4_lua_controller", {
+	description = "TA4 Lua Controller",
+	inventory_image = "techage_lua_controller_inventory.png",
+	wield_image = "techage_lua_controller_inventory.png",
+	stack_max = 1,
+	tiles = {
+		-- up, down, right, left, back, front
+		"techage_smartline.png",
+		"techage_smartline.png",
+		"techage_smartline.png",
+		"techage_smartline.png",
+		"techage_smartline.png",
+		"techage_smartline.png^techage_lua_controller.png",
+	},
+
+	drawtype = "nodebox",
+	node_box = {
+		type = "fixed",
+		fixed = {
+			{ -6/32, -6/32, 14/32,  6/32,  6/32, 16/32},
+		},
+	},
+	
+	after_place_node = function(pos, placer)
+		local meta = minetest.get_meta(pos)
+		local number = techage.add_node(pos, "techage:ta4_lua_controller")
+		meta:set_string("owner", placer:get_player_name())
+		meta:set_string("number", number)
+		meta:set_int("state", techage.STOPPED)
+		meta:set_int("running", STATE_STOPPED)
+		meta:set_string("init", "-- called only once")
+		meta:set_string("func", "-- for your functions")
+		meta:set_string("loop", "-- called every second")
+		meta:set_string("notes", "For your notes / snippets")
+		meta:mark_as_private("init")
+		meta:mark_as_private("func")
+		meta:mark_as_private("loop")
+		meta:mark_as_private("notes")
+		meta:set_string("formspec", formspec1(meta))
+		meta:set_string("infotext", "Controller "..number..": stopped")
+	end,
+
+	on_receive_fields = on_receive_fields,
+	
+	on_dig = function(pos, node, puncher, pointed_thing)
+		if minetest.is_protected(pos, puncher:get_player_name()) then
+			return
+		end
+		
+		minetest.node_dig(pos, node, puncher, pointed_thing)
+		techage.remove_node(pos)
+	end,
+	
+	on_timer = on_timer,
+	
+	paramtype = "light",
+	sunlight_propagates = true,
+	paramtype2 = "facedir",
+	groups = {choppy=1, cracky=1, crumbly=1},
+	is_ground_content = false,
+	sounds = default.node_sound_stone_defaults(),
+})
+
+
+minetest.register_craft({
+	output = "techage:ta4_lua_controller",
+	recipe = {
+		{"basic_materials:plastic_sheet", "dye:blue", "basic_materials:plastic_sheet"},
+		{"", "default:copper_ingot", ""},
+		{"techage:ta4_ramchip", "techage:ta4_wlanchip", "techage:ta4_ramchip"},
+	},
+})
+
+-- write inputs from remote nodes
+local function set_input(pos, number, input, val)
+	if input and M(pos):get_int("state") == techage.RUNNING then 
+		if (Cache[number] or compile(pos, M(pos), number)) and Cache[number].inputs then
+			if input == "msg" then
+				if #Cache[number].inputs["msg"] < 10 then
+					table.insert(Cache[number].inputs["msg"], val)
+				end
+			else
+				Cache[number].inputs[input] = val
+			end
+			if Cache[number].events then  -- events enabled?
+				local t = minetest.get_us_time()
+				 if not Cache[number].last_event or Cache[number].last_event < t then
+					local meta = minetest.get_meta(pos)
+					minetest.after(0.01, call_loop, pos, meta, -1)
+					Cache[number].last_event = t + 100000 -- add 100 ms
+				end
+			end
+		end
+	end
+end	
+
+-- used by the command "input"
+function techage.lua_ctlr.get_input(number, input)
+	if input then 
+		if Cache[number] and Cache[number].inputs then
+			return Cache[number].inputs[input] or "off"
+		end
+	end
+	return "off"
+end	
+
+-- used for Terminal commands
+function techage.lua_ctlr.get_command(number)
+	if Cache[number] and Cache[number].inputs then
+		local cmnd = Cache[number].inputs["term"]
+		Cache[number].inputs["term"] = nil
+		return cmnd
+	end
+end	
+
+-- used for queued messages
+function techage.lua_ctlr.get_msg(number)
+	if Cache[number] and Cache[number].inputs then
+		return table.remove(Cache[number].inputs["msg"], 1)
+	end
+end	
+
+techage.register_node({"techage:ta4_lua_controller"}, {
+	on_recv_message = function(pos, topic, payload)
+		local meta = minetest.get_meta(pos)
+		local number = meta:get_string("number")
+		
+		if topic == "on" then
+			set_input(pos, number, payload, topic)
+		elseif topic == "off" then
+			set_input(pos, number, payload, topic)
+		elseif topic == "term" then
+			set_input(pos, number, "term", payload)
+		elseif topic == "msg" then
+			set_input(pos, number, "msg", payload)
+		elseif topic == "state" then
+			local running = meta:get_int("running") or STATE_STOPPED
+			return techage.statestring(running)
+		else
+			return "unsupported"
+		end
+	end,
+})		
diff --git a/lua_controller/sensorchest.lua b/lua_controller/sensorchest.lua
new file mode 100644
index 0000000..a9b07ad
--- /dev/null
+++ b/lua_controller/sensorchest.lua
@@ -0,0 +1,193 @@
+--[[
+
+	TechAge
+	=======
+
+	Copyright (C) 2019-2020 Joachim Stolberg
+
+	GPL v3
+	See LICENSE.txt for more information
+	
+	TA4 Sensor Chest
+	
+]]--
+
+-- for lazy programmers
+local M = minetest.get_meta
+local S = techage.S
+
+local PlayerActions = {}
+local InventoryState = {}
+
+
+local function store_action(pos, player, action, stack)
+	local meta = minetest.get_meta(pos)
+	local name = player and player:get_player_name() or ""
+	local number = meta:get_string("node_number")
+	local item = stack:get_name().." "..stack:get_count()
+	PlayerActions[number] = {name, action, item}
+end	
+
+local function send_off_command(pos)
+	local meta = minetest.get_meta(pos)
+	local numbers = meta:get_string("numbers") or ""
+	if numbers ~= "" then
+		local own_num = meta:get_string("node_number")
+		techage.send_multi(own_num, numbers, "off")
+	end
+end
+
+
+local function send_command(pos)
+	local meta = minetest.get_meta(pos)
+	local numbers = meta:get_string("numbers") or ""
+	if numbers ~= "" then
+		local own_num = meta:get_string("node_number")
+		techage.send_multi(own_num, numbers, "on")
+		minetest.after(1, send_off_command, pos)
+	end
+end
+
+local function allow_metadata_inventory_put(pos, listname, index, stack, player)
+	if minetest.is_protected(pos, player:get_player_name()) then
+		return 0
+	end
+	store_action(pos, player, "put", stack)
+	send_command(pos)
+	return stack:get_count()
+end
+
+local function allow_metadata_inventory_take(pos, listname, index, stack, player)
+	if minetest.is_protected(pos, player:get_player_name()) then
+		return 0
+	end
+	store_action(pos, player, "take", stack)
+	send_command(pos)
+	return stack:get_count()
+end
+
+local function can_dig(pos, player)
+	if minetest.is_protected(pos, player:get_player_name()) then
+		return false
+	end
+	local inv = minetest.get_meta(pos):get_inventory()
+	return inv:is_empty("main")
+end
+
+local function after_dig_node(pos, oldnode, oldmetadata, digger)
+	techage.remove_node(pos)
+end
+
+local function formspec(pos)
+	local text = M(pos):get_string("text")
+	return "size[8,6]"..
+	default.gui_bg..
+	default.gui_bg_img..
+	default.gui_slots..
+	"list[context;main;0,0;2,2;]"..
+	"button[2,0;1,1;f1;F1]"..
+	"button[2,1;1,1;ok;OK]"..
+	"label[3,0;"..text.."]"..
+	"list[current_player;main;0,2.3;8,4;]"..
+	"listring[context;main]"..
+	"listring[current_player;main]"
+end
+
+minetest.register_node("techage:ta4_sensor_chest", {
+	description = S("TA4 Sensor Chest"),
+	tiles = {
+		-- up, down, right, left, back, front
+		"techage_filling_ta4.png^techage_frame_ta4_top.png",
+		"techage_filling_ta4.png^techage_frame_ta4.png",
+		"techage_filling_ta4.png^techage_frame_ta4.png^techage_appl_chest_back_ta4.png^techage_appl_sensor.png",
+		"techage_filling_ta4.png^techage_frame_ta4.png^techage_appl_chest_back_ta4.png^techage_appl_sensor.png",
+		"techage_filling_ta4.png^techage_frame_ta4.png^techage_appl_chest_back_ta4.png^techage_appl_sensor.png",
+		"techage_filling_ta4.png^techage_frame_ta4.png^techage_appl_chest_front_ta4.png^techage_appl_sensor.png",
+	},
+
+	on_construct = function(pos)
+		local meta = minetest.get_meta(pos)
+		local inv = meta:get_inventory()
+		inv:set_size('main', 4)
+	end,
+	
+	after_place_node = function(pos, placer)
+		local meta = minetest.get_meta(pos)
+		local number = techage.add_node(pos, "techage:ta4_sensor_chest")
+		meta:set_string("node_number", number)
+		meta:set_string("owner", placer:get_player_name())
+		meta:set_string("text", "Text to be changed\nby command.")
+		meta:set_string("formspec", formspec(pos))
+		meta:set_string("infotext", S("TA4 Sensor Chest").." "..number)
+	end,
+
+	on_receive_fields = function(pos, formname, fields, player)
+		local meta = M(pos)
+		local nvm = techage.get_nvm(pos)
+		if fields.f1 then
+			store_action(pos, player, "f1")
+			send_command(pos)
+		end
+		if fields.ok then
+			store_action(pos, player, "ok")
+			send_command(pos)
+		end
+		meta:set_string("formspec", formspec(pos, meta))
+	end,
+	
+	techage_set_numbers = function(pos, numbers, player_name)
+		return techage.logic.set_numbers(pos, numbers, player_name, S("TA4 Sensor Chest"))
+	end,
+	
+	can_dig = can_dig,
+	after_dig_node = after_dig_node,
+	allow_metadata_inventory_put = allow_metadata_inventory_put,
+	allow_metadata_inventory_take = allow_metadata_inventory_take,
+
+	paramtype2 = "facedir",
+	groups = {choppy=2, cracky=2, crumbly=2},
+	is_ground_content = false,
+	sounds = default.node_sound_wood_defaults(),
+})
+
+techage.register_node({"ta4_sensor_chest"}, {
+	on_pull_item = function(pos, in_dir, num)
+		local meta = minetest.get_meta(pos)
+		local inv = meta:get_inventory()
+		return techage.get_items(inv, "main", num)
+	end,
+	on_push_item = function(pos, in_dir, stack)
+		local meta = minetest.get_meta(pos)
+		local inv = meta:get_inventory()
+		return techage.put_items(inv, "main", stack)
+	end,
+	on_unpull_item = function(pos, in_dir, stack)
+		local meta = minetest.get_meta(pos)
+		local inv = meta:get_inventory()
+		return techage.put_items(inv, "main", stack)
+	end,
+	
+	on_recv_message = function(pos, src, topic, payload)
+		if topic == "state" then
+			local meta = minetest.get_meta(pos)
+			local inv = meta:get_inventory()
+			return techage.get_inv_state(inv, "main")
+		elseif topic == "player_action" then
+			local meta = minetest.get_meta(pos)
+			local number = meta:get_string("node_number")
+			return PlayerActions[number]
+		elseif topic == "text" then
+			local meta = minetest.get_meta(pos)
+			meta:set_string("text", tostring(payload))
+		else
+			return "unsupported"
+		end
+	end,
+})	
+
+minetest.register_craft({
+	type = "shapeless",
+	output = "techage:ta4_sensor_chest",
+	recipe = {"techage:chest_ta4", "techage:ta4_wlanchip"}
+})
+
diff --git a/lua_controller/server.lua b/lua_controller/server.lua
new file mode 100644
index 0000000..d0ae8b6
--- /dev/null
+++ b/lua_controller/server.lua
@@ -0,0 +1,232 @@
+--[[
+
+	sl_controller
+	=============
+
+	Copyright (C) 2018 Joachim Stolberg
+
+	LGPLv2.1+
+	See LICENSE.txt for more information
+
+	server.lua:
+
+]]--
+
+local SERVER_CAPA = 5000
+local DEFAULT_MEM = {
+	size=0, 
+	data={
+		version = 1,
+		info = "SaferLua key/value Server",
+	}
+}
+
+local function formspec(meta)
+	local names = meta:get_string("names") or ""
+	return "size[9,4]"..
+	default.gui_bg..
+	default.gui_bg_img..
+	default.gui_slots..
+	"field[0.2,1;9,1;names;Allowed user names (spaces separated):;"..names.."]" ..
+	"button_exit[3.5,2.5;2,1;exit;Save]"
+end
+
+
+local function on_time(pos, elasped)
+	local meta = minetest.get_meta(pos)
+	local nvm = techage.get_nvm(pos)
+	if next(nvm) == nil then
+		nvm = table.copy(DEFAULT_MEM)
+	end
+	local number = meta:get_string("number")
+	meta:set_string("infotext", "Server "..number..": ("..(nvm.size or 0).."/"..SERVER_CAPA..")")
+	return true
+end
+
+minetest.register_node("techage:ta4_server", {
+	description = "Central Server",
+	tiles = {
+		-- up, down, right, left, back, front
+		"techage_server_top.png",
+		"techage_server_top.png",
+		"techage_server_side.png",
+		"techage_server_side.png^[transformFX",
+		"techage_server_back.png",
+		{
+			image = "techage_server_front.png",
+			backface_culling = false,
+			animation = {
+				type = "vertical_frames",
+				aspect_w = 32,
+				aspect_h = 32,
+				length = 1,
+			},
+		},
+	},
+
+	drawtype = "nodebox",
+	node_box = {
+		type = "fixed",
+		fixed = {
+			{ -3/16, -8/16, -7/16, 3/16, 6/16, 7/16},
+		},
+	},
+	
+	after_place_node = function(pos, placer)
+		local meta = minetest.get_meta(pos)
+		local number = techage.add_node(pos, "techage:ta4_server")
+		meta:set_string("owner", placer:get_player_name())
+		meta:set_string("number", number)
+		meta:set_string("formspec", formspec(meta))
+		on_time(pos, 0)
+		minetest.get_node_timer(pos):start(20)
+	end,
+	
+	on_receive_fields = function(pos, formname, fields, player)
+		local meta = minetest.get_meta(pos)
+		local owner = meta:get_string("owner")
+		if player:get_player_name() == owner then
+			if fields.names and fields.names ~= "" then
+				local names = string.gsub(fields.names, " +", " ")
+				meta:set_string("names", names)
+				meta:set_string("formspec", formspec(meta))
+			end
+		end
+	end,
+	
+	on_dig = function(pos, node, puncher, pointed_thing)
+		if minetest.is_protected(pos, puncher:get_player_name()) then
+			return
+		end
+		local meta = minetest.get_meta(pos)
+		local number = meta:get_string("number")
+		techage.del_mem(pos)
+		minetest.node_dig(pos, node, puncher, pointed_thing)
+		techage.remove_node(pos)
+	end,
+		
+	on_timer = on_time,
+	
+	paramtype = "light",
+	sunlight_propagates = true,
+	paramtype2 = "facedir",
+	groups = {choppy=1, cracky=1, crumbly=1},
+	is_ground_content = false,
+	sounds = default.node_sound_stone_defaults(),
+})
+
+minetest.register_craft({
+	output = "techage:ta4_server",
+	recipe = {
+		{"default:steel_ingot", "dye:black", "default:steel_ingot"},
+		{"techage:ta4_ramchip", "default:copper_ingot", "techage:ta4_ramchip"},
+		{"techage:ta4_ramchip", "techage:ta4_wlanchip", "techage:ta4_ramchip"},
+	},
+})
+
+local function calc_size(v)
+	if type(v) == "number" then
+		return 1
+	elseif v == nil then
+		return 0
+	elseif type(v) == "string" then
+		return #v
+	elseif v.MemSize then
+		return v.MemSize
+	else
+		return nil
+	end
+end
+
+local function get_memory(pos, num, name)
+	local info = techage.get_node_info(num)
+	if info and info.name == "techage:ta4_server" then
+		local meta = minetest.get_meta(info.pos)
+		local owner = meta:get_string("owner")
+		if name == owner then
+			local nvm = techage.get_nvm(pos)
+			if next(nvm) == nil then
+				nvm = table.copy(DEFAULT_MEM)
+			end
+			return nvm
+		end
+		local names = meta:get_string("names")
+		for _,n in ipairs(string.split(names, " ")) do
+			local nvm = techage.get_nvm(pos)
+			if name == n then
+				if next(nvm) == nil then
+					nvm = table.copy(DEFAULT_MEM)
+				end
+				return nvm
+			end
+		end
+	end
+end
+
+local function write_value(nvm, key, item)
+	if nvm and nvm.size < SERVER_CAPA then
+		if nvm.data[key] then
+			nvm.size = nvm.size - calc_size(nvm.data[key])
+		end
+		if type(item) == "table" then
+			item = safer_lua.datastruct_to_table(item)
+		end
+		nvm.size = nvm.size + calc_size(item)
+		nvm.data[key] = item
+	end
+end	
+
+local function read_value(nvm, key)
+	local item = nvm.data[key]
+	if type(item) == "table" then
+		item = safer_lua.table_to_datastruct(item)
+	end
+	return item
+end	
+
+techage.register_node({"techage:ta4_server"}, {
+	on_recv_message = function(pos, topic, payload)
+		return "unsupported"
+	end,
+	on_node_load = function(pos)
+		minetest.get_node_timer(pos):start(20)
+	end,
+})		
+
+
+techage.lua_ctlr.register_function("server_read", {
+	cmnd = function(self, num, key) 
+		if type(key) == "string" then
+			local nvm = get_memory(self.meta.pos, num, self.meta.owner)
+			if nvm then
+				return read_value(nvm, key)
+			end
+		else
+			self.error("Invalid server_read parameter")
+		end
+	end,
+	help = " $server_read(num, key)\n"..
+		" Read a value from the server.\n"..
+		" 'key' must be a string.\n"..
+		' example: state = $server_read("0123", "state")'
+})
+
+techage.lua_ctlr.register_action("server_write", {
+	cmnd = function(self, num, key, value)
+		if type(key) == "string" then
+			local nvm = get_memory(self.meta.pos, num, self.meta.owner)
+			if nvm then
+				write_value(nvm, key, value)
+			end
+		else
+			self.error("Invalid server_write parameter")
+		end
+	end,
+	help = " $server_write(num, key, value)\n"..
+		" Store a value on the server under the key 'key'.\n"..
+		" 'key' must be a string. 'value' can be either a\n"..
+		" number, string, boolean, nil or data structure.\n"..
+		' example: $server_write("0123", "state", state)'
+})
+
+
diff --git a/power/power_terminal.lua b/power/power_terminal.lua
index da2efc6..ca858c2 100644
--- a/power/power_terminal.lua
+++ b/power/power_terminal.lua
@@ -212,7 +212,7 @@ minetest.register_node("techage:power_terminal", {
 	on_rotate = screwdriver.disallow,
 	sunlight_propagates = true,
 	is_ground_content = false,
-	groups = {cracky = 1, level = 2},
+	groups = {cracky = 2, level = 2},
 	sounds = default.node_sound_metal_defaults(),
 })
 
diff --git a/textures/techage_appl_sensor.png b/textures/techage_appl_sensor.png
new file mode 100644
index 0000000..e3bdead
Binary files /dev/null and b/textures/techage_appl_sensor.png differ