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@@ -1,2 +1,44 @@
-# smart-domofon
-Smart intercom with MQTT based on NodeMCUv3
+# Smart intercom with MQTT based on NodeMCUv3
+
+This device can send "door open" command to intercom main unit after receiving of incoming call. It only works with coordinate line intercoms. Tested with Cyfral russian intercom.
+
+Thanks to [Metori](https://github.com/Metori) for [original progect](https://github.com/Metori/mqtt_domofon)
+
+## Parts used:
+* NodeMCU v3 x 1
+* Double relay module x1 (or two single relay modules)
+* LED x3 (or one RGB LED)
+* Button x2
+* Optocoupler x1
+* Some resistors
+
+## Status MQTT messages (domofon/status):
+* 'R' - ready; sent after successfull boot-up or after receiving of 'P' message
+* 'L' - last will message; send when device goes offline
+
+## Incoming MQTT messages (domofon/in):
+* 'O' - door open command
+* 'N' - call reject command (door will not open)
+* 'P' - ping command (answers with 'R')
+
+## Outgoing MQTT messages (domofon/out):
+* 'C' - call; sent after detecting of incoming intercom call
+* 'H' - hangup; sent after detected incoming call finished
+* 'B' - button; sent when "door open" has been performed by green hw button press
+* 'J' - reJected; sent when incoming call has been rejected by red hw button press
+* 'S' - success; sent in response to 'O' or 'N' command
+* 'F' - fail; sent in response to 'O' or 'N' command (this means that 'O' or 'N' command has been received but no incoming call detected)
+
+## Home Assistant configuration
+```
+binary_sensor:
+  - platform: mqtt
+    name: "Domofon"
+    state_topic: "domofon/out"
+    availability_topic: "domofon/status"
+    payload_on: "C"
+    payload_off: "H"
+    payload_available: "R"
+    payload_not_available: "L"
+    device_class: lock
+```