diff --git a/tubes/signal.lua b/tubes/signal.lua
index 6e80dda..4b25b1a 100644
--- a/tubes/signal.lua
+++ b/tubes/signal.lua
@@ -1,70 +1,104 @@
+-- luacheck: globals DIR_DELIM
+
 local S = core.get_translator("pipeworks")
+local storage = core.get_mod_storage()
+local STORAGE_PREFIX = "detector_timer_"
 
--- the core.after() calls below can sometimes trigger after a tube
--- breaks, at which point item_exit() is no longer valid, so we have to make
--- sure that there even IS a callback to run, first.
+if core.get_modpath("mesecons") and pipeworks.enable_detector_tube then
+	local detector_tube_step = 5 * (tonumber(core.settings:get("dedicated_server_step")) or 0.09)
 
-local function after_break(pos)
-	local name = core.get_node(pos).name
-	if core.registered_nodes[name].item_exit then
-		core.registered_nodes[name].item_exit(pos)
+	-- in-memory table to avoid traversing the whole storage in globalstep
+	-- { [position_hash] = time }
+	local detector_timers = {}
+
+	-- populate our in-memory table from storage
+	for key, val in pairs(storage:to_table().fields) do
+		local short_key = string.match(key, "^"..STORAGE_PREFIX.."(.+)")
+		if short_key then
+			local hash = tonumber(short_key)
+			detector_timers[hash] = tonumber(val)
+		end
+	end
+
+	local function detector_set_timer(pos, time)
+		local hash = core.hash_node_position(pos)
+		time = time or detector_tube_step
+		-- timer will be refreshed if already set
+		detector_timers[hash] = time
+		storage:set_float(string.format("%s%.0f", STORAGE_PREFIX, hash), time)
+	end
+
+	local function detector_remove_timer(pos)
+		local hash = core.hash_node_position(pos)
+		detector_timers[hash] = nil
+		storage:set_string(string.format("%s%.0f", STORAGE_PREFIX, hash), "")
+	end
+
+	core.register_globalstep(function(dtime)
+		for hash, time in pairs(detector_timers) do
+			local pos = core.get_position_from_hash(hash)
+			time = time - dtime
+			if time <= 0 then
+				local node = core.get_node_or_nil(pos)
+				if node then
+					detector_remove_timer(pos)
+					if string.find(node.name, "pipeworks:detector_tube_on_", 1, true) then
+						node.name = string.gsub(node.name, "on", "off", 1)
+						core.swap_node(pos, node)
+						mesecon.receptor_off(pos, pipeworks.mesecons_rules)
+					end
+				end
+				-- in case the area wasn't loaded, do not remove the timer
+			else
+				detector_set_timer(pos, time)
+			end
+		end
+	end)
+
+	-- cleanup metadata from previous versions
+	local function detector_cleanup_metadata(pos)
+		local meta = core.get_meta(pos)
+		if not meta then return end
+		-- an empty string deletes the key even if the previous value wasn't a string
+		meta:set_string("nitems", "")
 	end
-end
 
-if core.get_modpath("mesecons") and pipeworks.enable_detector_tube then
-	local detector_tube_step = 5 * (tonumber(core.settings:get("dedicated_server_step")) or 0.09)
 	pipeworks.register_tube("pipeworks:detector_tube_on", {
 			description = S("Detecting Pneumatic Tube Segment on"),
 			inventory_image = "pipeworks_detector_tube_inv.png",
 			plain = { "pipeworks_detector_tube_plain.png" },
 			node_def = {
-				tube = {can_go = function(pos, node, velocity, stack)
-						 local meta = core.get_meta(pos)
-						 local nitems = meta:get_int("nitems")+1
-						 meta:set_int("nitems", nitems)
-						 local saved_pos = vector.new(pos)
-						 core.after(detector_tube_step, after_break, saved_pos)
-						 return pipeworks.notvel(pipeworks.meseadjlist,velocity)
-					end},
+				tube = {
+					can_go = function(pos, node, velocity, stack)
+						detector_cleanup_metadata(pos)
+						detector_set_timer(pos)
+						return pipeworks.notvel(pipeworks.meseadjlist, velocity)
+					end,
+				},
 				groups = {mesecon = 2, not_in_creative_inventory = 1},
 				drop = "pipeworks:detector_tube_off_1",
 				mesecons = {receptor = {state = "on", rules = pipeworks.mesecons_rules}},
-				item_exit = function(pos)
-					local meta = core.get_meta(pos)
-					local nitems = meta:get_int("nitems")-1
-					local node = core.get_node(pos)
-					local name = node.name
-					local fdir = node.param2
-					if nitems == 0 then
-						 core.set_node(pos, {name = string.gsub(name, "on", "off"), param2 = fdir})
-						 mesecon.receptor_off(pos, pipeworks.mesecons_rules)
-					else
-						 meta:set_int("nitems", nitems)
-					end
-				end,
-				on_construct = function(pos)
-					 local meta = core.get_meta(pos)
-					 meta:set_int("nitems", 1)
-					 core.after(detector_tube_step, after_break, pos)
-				end,
 			},
 	})
+
 	pipeworks.register_tube("pipeworks:detector_tube_off", {
-			description = S("Detecting Pneumatic Tube Segment"),
-			inventory_image = "pipeworks_detector_tube_inv.png",
-			plain = { "pipeworks_detector_tube_plain.png" },
-			node_def = {
-				tube = {can_go = function(pos, node, velocity, stack)
-						local node = core.get_node(pos)
-						local name = node.name
-						local fdir = node.param2
-						core.set_node(pos,{name = string.gsub(name, "off", "on"), param2 = fdir})
-						mesecon.receptor_on(pos, pipeworks.mesecons_rules)
-						return pipeworks.notvel(pipeworks.meseadjlist, velocity)
-					end},
-				groups = {mesecon = 2},
-				mesecons = {receptor = {state = "off", rules = pipeworks.mesecons_rules }},
+		description = S("Detecting Pneumatic Tube Segment"),
+		inventory_image = "pipeworks_detector_tube_inv.png",
+		plain = {"pipeworks_detector_tube_plain.png"},
+		node_def = {
+			tube = {
+				can_go = function(pos, node, velocity, stack)
+					detector_cleanup_metadata(pos)
+					node.name = string.gsub(node.name, "off", "on", 1)
+					core.swap_node(pos, node)
+					mesecon.receptor_on(pos, pipeworks.mesecons_rules)
+					detector_set_timer(pos)
+					return pipeworks.notvel(pipeworks.meseadjlist, velocity)
+				end,
 			},
+			groups = {mesecon = 2},
+			mesecons = {receptor = {state = "off", rules = pipeworks.mesecons_rules}},
+		},
 	})
 
 	core.register_craft( {