diff --git a/src/trekstor.rs b/src/trekstor.rs
index 44887b8..68f67bb 100644
--- a/src/trekstor.rs
+++ b/src/trekstor.rs
@@ -51,6 +51,7 @@ impl Trekstor {
             self.input.finish();
 
             self.last_time = self.current_time;
+            let dt = self.current_time - self.last_time;
             if dt < self.update_timestep {
                 sleep(self.update_timestep - dt);
             }