diff --git a/API.md b/API.md
index 6fbb652..2a6edca 100644
--- a/API.md
+++ b/API.md
@@ -39,6 +39,19 @@
 	}
 	```
 
+* Sound sensor
+
+	Topic: `sound`
+
+	Data example:
+
+	```json
+	{
+		"deviceId": 0,
+		"value": 3072
+	}
+	```
+
 * Door lock
 
 	Topic: `door/lock/{deviceId}/lock`