diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..665979e
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "cadmodel-sg90"]
+	path = cadmodel-sg90
+	url = https://github.com/ledalert/cadmodel-sg90.git
diff --git a/cadmodel-sg90 b/cadmodel-sg90
new file mode 160000
index 0000000..2aba157
--- /dev/null
+++ b/cadmodel-sg90
@@ -0,0 +1 @@
+Subproject commit 2aba157f6aa121d7a08217885196b563c99a30ab
diff --git a/katzenklappe.scad b/katzenklappe.scad
index 8c785fd..ecf8518 100644
--- a/katzenklappe.scad
+++ b/katzenklappe.scad
@@ -1,7 +1,12 @@
-angle = 20;
+use <cadmodel-sg90/sg90.scad>;
+use <cadmodel-sg90/fastener_1.scad>;
+
+flap_angle = 0;
+servo_angle = -10;
 axle_dia = 4;
 axle_len = 40;
 raise = 0;
+
 tunnel_w = 160;
 tunnel_h = 160;
 tunnel_t = 10; // tunnel thickness
@@ -130,7 +135,7 @@ module axles(){
 }
 
 module flap(){
-    translate(z*(sheet_h-rad)/2) rotate(x*angle) {
+    translate(z*(sheet_h-rad)/2) rotate(x*flap_angle) {
         difference(){
             rotate(y*90) cylinder(d=2*rad,h=tunnel_w-2*seal,center=true);
             sheets();
@@ -155,7 +160,17 @@ module flap(){
     }
 }
 
-*door();
+module servo(){
+    translate(-[5.5,0,28.5]) sg90();
+    rotate(servo_angle*z) sg90_f1();
+}
+
+module servo_in_place(){
+    translate([-11,0,-tunnel_h/2 -10])rotate(90*x)servo();
+}
+
+door();
 tunnel();
 flap();
 axles();
+servo_in_place();