diff --git a/manager/display.lua b/manager/display.lua
index 588f3c2..0a5e90c 100644
--- a/manager/display.lua
+++ b/manager/display.lua
@@ -163,15 +163,30 @@ function D.setupSmelterMonitor()
 end
 
 function D.setupBillboardMonitor()
-    if not cfg.BILLBOARD_MONITOR or cfg.BILLBOARD_MONITOR == "" then
+    -- If explicitly configured, use that name
+    if cfg.BILLBOARD_MONITOR and cfg.BILLBOARD_MONITOR ~= "" then
+        local mon = peripheral.wrap(cfg.BILLBOARD_MONITOR)
+        if mon and mon.setTextScale then
+            D.billboardMon = mon
+            D.billboardMonName = cfg.BILLBOARD_MONITOR
+            D.billboardMon.setTextScale(0.5)
+            return true
+        end
         return false
     end
-    local mon = peripheral.wrap(cfg.BILLBOARD_MONITOR)
-    if mon and mon.setTextScale then
-        D.billboardMon = mon
-        D.billboardMonName = cfg.BILLBOARD_MONITOR
-        D.billboardMon.setTextScale(0.5)
-        return true
+    -- Auto-detect: find any monitor not already used by main/smelter
+    for _, name in ipairs(peripheral.getNames()) do
+        if peripheral.getType(name) == "monitor"
+           and name ~= D.monName
+           and name ~= D.smelterMonName then
+            local mon = peripheral.wrap(name)
+            if mon and mon.setTextScale then
+                D.billboardMon = mon
+                D.billboardMonName = name
+                D.billboardMon.setTextScale(0.5)
+                return true
+            end
+        end
     end
     return false
 end