diff --git a/README.md b/README.md
index ed172a0..e403190 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ Code: Licensed under the GNU LGPL version 2.1 or later. See LICENSE.txt
 
 
 ### Dependencies 
-default, farming
+default, farming, basic_materials, tubelib2
 
 ### History
 - 2019-03-23  v0.01  * first draft
diff --git a/depends.txt b/depends.txt
index 1c94e74..f342287 100644
--- a/depends.txt
+++ b/depends.txt
@@ -1 +1,4 @@
-default, farming, tubelib2
+default
+farming
+basic_materials
+tubelib2
diff --git a/logic.lua b/logic.lua
index 8bb667a..96fc4c1 100644
--- a/logic.lua
+++ b/logic.lua
@@ -59,7 +59,7 @@ local function switch_sign_changer(pos, new_idx)
 	node.name = "signs_bot:changer"..new_idx
 	minetest.swap_node(pos, node)
 	-- swap sign
-	local param2 = minetest.get_node(pos).param2
+	local param2 = minetest.get_node(pos1).param2
 	local sign = lib.dig_sign(pos1)
 	if sign then
 		M(pos):set_int("sign_param2_"..old_idx, param2)
diff --git a/mod.conf b/mod.conf
index c85672f..23894c5 100644
--- a/mod.conf
+++ b/mod.conf
@@ -1,4 +1,3 @@
 name=signs_bot
-depends = default, farming, tubelib2
-optional_depends = tubelib
+depends = default,farming,basic_materials,tubelib2
 description = A robot controlled by signs
\ No newline at end of file