diff --git a/src/home_assistant/object_id.rs b/src/home_assistant/object_id.rs
index 501cf38..b734e02 100644
--- a/src/home_assistant/object_id.rs
+++ b/src/home_assistant/object_id.rs
@@ -19,6 +19,7 @@ impl FromStr for ObjectId {
         for c in s.chars() {
             match c {
                 'a'..='z' => {}
+                '0'..='9' => {}
                 '_' => {}
                 _ => return Err(ObjectIdParsingError { encountered: c }),
             }