diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..01498d9
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "software/libcariboulite/src/iir"]
+	path = software/libcariboulite/src/iir
+	url = https://github.com/berndporr/iir1
diff --git a/software/libcariboulite/src/iir b/software/libcariboulite/src/iir
new file mode 160000
index 0000000..fc8634d
--- /dev/null
+++ b/software/libcariboulite/src/iir
@@ -0,0 +1 @@
+Subproject commit fc8634d15b470a00ba4859915fec0047bb486dd4