Choosing the right automated parking system sensors is essential for improving occupancy detection accuracy, operational efficiency, and user experience. This guide compares ultrasonic, geomagnetic, AI camera, radar, LiDAR, and GPS technologies while explaining their applications, advantages, and limitations. It also explores network connectivity, edge computing, AI-based detection, and deployment strategies to help developers and parking operators build reliable, scalable, and high-performance smart parking systems for a wide range of environments.