diff --git a/README.md b/README.md
index 8e1dabc..0f2df54 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,9 @@
 - https://www.mikrocontroller.net/topic/442157
 - https://gist.github.com/denalena/b043b2f46fe9475c37c01a16c923efc3
 
+### Specialized for the BTS 850-02
+- https://forum.allaboutcircuits.com/threads/need-help-with-controlling-a-door-circuit.132834/
+
 ## Potential entry points
 - Wifi -> fritz.box -> sip
 - Wifi -> Homeassistant esphome