diff --git a/compacting-storage.lua b/compacting-storage.lua
index 99df3ac..7d46c52 100644
--- a/compacting-storage.lua
+++ b/compacting-storage.lua
@@ -71,9 +71,9 @@ end
 
 -- logic
 
-function sum_items (inv)
+function sum_items (inv_f)
     local result = {}
-    for _, item in pairs(inv.list()) do
+    for _, item in pairs(inv_f()) do
         if result[item.name] == nil then result[item.name] = 0 end
         result[item.name] = result[item.name] + item.count
     end
@@ -156,8 +156,9 @@ function print_counts (items)
 end
 
 while true do
+    local main_inv = peripheral.wrap(MAIN_TICKER)
     -- 1. Sum items in inventory and organize by item type
-    local items = sum_items(peripheral.wrap(INVENTORY))
+    local items = sum_items(main_inv.stock)
     -- print_counts(items)
 
     -- 2. either work towards a desired distribution or create more resources