This study focuses on internal resonance (IR) and mode localization (ML), investigating their connection. Steady-state equations are derived using the perturbation method of multiple scales. An adjustable coupling mechanism based on ML and IR principles is constructed and validated through simulations and equivalent experiments. The effectiveness of the mechanism of converting the IR into ML by changing the coupling strength is verified by numerical simulation, and the influence of relevant parameters on the vibration response of the system is analyzed. The theoretical understanding paves the way for potential sensing applications. The goal is to create a self-powered sensor that harvests energy in the IR state and senses in the ML state, with applications in environmental monitoring, biomedics, and public safety, addressing challenges like smog, influenza, and gas leaks.