A home indoor positioning system (HIPS) is a positioning system that provides location information of mobile devices, such as smartphones, for location-based IoT applications in a home environment. This paper introduces methods and algorithms to construct an HIPS using Wi-Fi signals. In the proposed system, an intelligent mobile robot, such as a home vacuum robot, is utilized to automatically construct radio maps for the system. Along with radio maps, the system adopts new algorithms to provide highly accurate positioning services and provides interfaces to support variable location-based IoT applications.