One-key start/stop bistable relay module for automobile refitting. It provides a convenient one-key start and stop function, simplifying operation during installation and use. Self-locking design delivers stable control during the start/stop process, ensuring reliable, repeatable performance. Controlled by a 51 (5V) single-chip microcomputer, this module enables precise and efficient management of the start/stop sequence. Compact module design and straightforward integration with the automobile electrical system allow a seamless upgrade without major modifications. Simplifies traditional starting and stopping procedures, making the automobile refitting process more user-friendly and efficient. Key benefits and attributes - Function: one-key start/stop operation with bistable relays for reliable state retention - Compatibility: designed for easy integration into standard automobile electrical systems - Size: compact design suitable for retrofit projects and tight installation spaces - Performance: stable, precise control of start/stop sequences via 51 (5V) microcontroller 2-3 practical use scenarios - Retrofit a personal car to enable one-key start/stop, reducing driving effort and streamlining daily use - Upgrade fleet vehicles (taxis, delivery vans) to deliver quicker, more consistent start/stop operation for drivers - Install in custom builds or hobby automotive projects to simplify start/stop control and improve user experience