The Samsung SHP-R80 worked perfectly on the first night. However, starting at 11 PM on the second night, it began making noises every 30–60 minutes for no apparent reason. It completely disrupted my sleep, and the manual provided no clear instructions on how to fix the issue. I contacted DDL, and they suggested removing the battery, which stopped the noise, but now the lock is operating manually. I’m still waiting for someone to resolve the problem. Disappointing experience so far for such an expensive product.