diff -u -r "Inventory Sensor_1.7.3/changelog.txt" "Inventory Sensor_1.7.4/changelog.txt"
--- "Inventory Sensor_1.7.3/changelog.txt"	2019-04-15 18:48:12.000000000 +0200
+++ "Inventory Sensor_1.7.4/changelog.txt"	2019-07-25 11:02:12.278789919 +0200
@@ -1,4 +1,9 @@
 ---------------------------------------------------------------------------------------------------
+Version: 1.7.4
+Date: 2019-07-25
+  Features:
+    - read inventory stack size if this is supported (wagons only)
+---------------------------------------------------------------------------------------------------
 Version: 1.7.3
 Date: 2019-04-15
   Features:
diff -u -r "Inventory Sensor_1.7.3/control.lua" "Inventory Sensor_1.7.4/control.lua"
--- "Inventory Sensor_1.7.3/control.lua"	2019-07-25 10:33:13.453732723 +0200
+++ "Inventory Sensor_1.7.4/control.lua"	2019-07-25 10:58:25.362519650 +0200
@@ -47,6 +47,7 @@
 local signal_progress = {type = "virtual",name = "inv-sensor-progress"}
 local signal_temperature = {type = "virtual",name = "inv-sensor-temperature"}
 local signal_fuel = {type = "virtual",name = "inv-sensor-fuel"}
+local signal_stack_size = {type = "virtual",name = "inv-sensor-stack-size-signal"}
 
 local floor = math.floor
 local ceil = math.ceil
@@ -377,12 +378,19 @@
     end
   end
 
+  local stack_size_combined = 0
+
   -- get items in all inventories
   for inv_index, inv in pairs(itemSensor.Inventory) do
-     local contentsTable = inv.get_contents()
-     log('---')
-     log(inv.getbar())
-     log('---')
+    local contentsTable = inv.get_contents()
+
+    -- Hotbar is this fancy red cross in practically every
+    -- inventory. getbar() returns its position, so we need to substract 1
+    -- from it to return maximum wagon stack size from it
+    if inv.hasbar() then
+      stack_size_combined = stack_size_combined + inv.getbar() - 1 
+    end
+
     for k,v in pairs(contentsTable) do
       signals[signalIndex] = { index = signalIndex, signal = {type = "item",name = k}, count = v }
       signalIndex = signalIndex+1
@@ -392,6 +400,12 @@
       end
     end
   end
+  
+  -- Set inventory stack size signal
+  if stack_size_combined > 0 then
+    signals[signalIndex] = { index = signalIndex, signal = signal_stack_size, count = stack_size_combined}
+    signalIndex = signalIndex+1    
+  end
 
   -- get remaining fuel from burner
   if burner then
diff -u -r "Inventory Sensor_1.7.3/info.json" "Inventory Sensor_1.7.4/info.json"
--- "Inventory Sensor_1.7.3/info.json"	2019-04-15 18:40:18.000000000 +0200
+++ "Inventory Sensor_1.7.4/info.json"	2019-07-25 11:02:28.626805465 +0200
@@ -1,6 +1,6 @@
 {
   "name": "Inventory Sensor",
-  "version": "1.7.3",
+  "version": "1.7.4",
   "title": "Inventory Sensor",
   "author": "Optera",
   "contact": "https://forums.factorio.com/memberlist.php?mode=viewprofile&u=21729",
Only in Inventory Sensor_1.7.4: inventory_sensor_stack_size_feature.patch
diff -u -r "Inventory Sensor_1.7.3/locale/de/de.cfg" "Inventory Sensor_1.7.4/locale/de/de.cfg"
--- "Inventory Sensor_1.7.3/locale/de/de.cfg"	2019-02-14 11:29:04.000000000 +0100
+++ "Inventory Sensor_1.7.4/locale/de/de.cfg"	2019-07-25 10:49:24.553163903 +0200
@@ -15,3 +15,4 @@
 inv-sensor-temperature=Temperatur
 inv-sensor-progress=Fortschritt
 inv-sensor-fuel=Brennstoff (MJ)
+inv-sensor-stack-size-signal=Stapelgrösse
\ No newline at end of file
diff -u -r "Inventory Sensor_1.7.3/locale/en/en.cfg" "Inventory Sensor_1.7.4/locale/en/en.cfg"
--- "Inventory Sensor_1.7.3/locale/en/en.cfg"	2019-02-14 11:28:36.000000000 +0100
+++ "Inventory Sensor_1.7.4/locale/en/en.cfg"	2019-07-25 10:48:25.536893838 +0200
@@ -15,6 +15,7 @@
 inv-sensor-temperature=Temperature
 inv-sensor-progress=Crafting Progress
 inv-sensor-fuel=Remaining fuel (MJ)
+inv-sensor-stack-size-signal=Stack size signal
 
 [mod-setting-name]
 inv_sensor_update_interval=Inventory update interval (ticks)
diff -u -r "Inventory Sensor_1.7.3/migrations/1.4.6.json" "Inventory Sensor_1.7.4/migrations/1.4.6.json"
--- "Inventory Sensor_1.7.3/migrations/1.4.6.json"	2017-06-02 11:21:12.000000000 +0200
+++ "Inventory Sensor_1.7.4/migrations/1.4.6.json"	2019-07-25 10:53:23.973932347 +0200
@@ -4,6 +4,7 @@
     ["detected-car", "inv-sensor-detected-car"],
     ["detected-tank", "inv-sensor-detected-tank"],
     ["detected-wagon", "inv-sensor-detected-wagon"],
-    ["detected-locomotive", "inv-sensor-detected-locomotive"]
+    ["detected-locomotive", "inv-sensor-detected-locomotive"],
+    ["stack-size-signal", "inv-sensor-stack-size-signal"]
   ]
-}
\ No newline at end of file
+}
diff -u -r "Inventory Sensor_1.7.3/prototypes/signal.lua" "Inventory Sensor_1.7.4/prototypes/signal.lua"
--- "Inventory Sensor_1.7.3/prototypes/signal.lua"	2019-02-14 11:51:28.000000000 +0100
+++ "Inventory Sensor_1.7.4/prototypes/signal.lua"	2019-07-25 10:46:16.795978867 +0200
@@ -69,5 +69,15 @@
     },
     subgroup = "sensor-signals",
     order = "x[sensor-signals]-dc"
-  }
-})
\ No newline at end of file
+  },
+{
+    type = "virtual-signal",
+    name = "inv-sensor-stack-size-signal",
+    icons = {
+      { icon = "__base__/graphics/icons/signal/signal_green.png", icon_size = 32 },
+      { icon = "__base__/graphics/icons/steel-chest.png", icon_size = 32, scale = 0.75 },
+    },
+    subgroup = "sensor-signals",
+    order = "x[sensor-signals]-dc"
+  }  
+})