The Charther developed with Marvelworks is a light, portable sensor device that detects the wetness and moisture of diapers or clothes of the user's baby and provides instructional sounds to the users. The sensor is designed with a smooth, intuitive USB-like appearance which offers portability to the user and integrates technologies with daily life. It fits a moisture sensor with PCB, and a lithium button battery well, with an additional springless manual clip that improves the safety of its usage and tightly sandwich the detected object when using. The water-proof button battery is protected by a carefully designed cap with living hinges that requires a tool to lift up, this prevents children and babies from taking out the button battery and swallowing it by accident. The structures of POM enhances the mechanical strength of the product.