You can't. It is illegal to install monitoring in the room of foot bath shop, which violates the privacy of guests. According to Article 132 of the Civil Law of People's Republic of China (PRC), any organization or individual working together shall not invade the privacy of others by spying, harassing, exposing or making public. Privacy is the private space, private activities and private information that natural people live in peace and don't want to be known by others. Article 103 Unless otherwise provided by law or expressly agreed by the obligee, no organization or individual may commit the following acts: (1) Interfere with the private life of others by means of telephone, short messages, instant messaging tools, e-mail, leaflets, etc. ; (2) Entering, taking photos or peeping into other people's private spaces such as houses and hotel rooms; (3) Shooting, peeping, eavesdropping or revealing other people's private activities; (4) Shooting or peeping at the private parts of others' bodies; (5) handling other people's private information; (6) Infringe upon the privacy of others in other ways.