This course provides a comprehensive introduction to sensors and sensing systems, covering fundamental principles, sensor characteristics, and physical sensing mechanisms. Topics include the electrical and material properties underlying sensor operation, sensor electronics, and signal processing. Various sensor types, such as motion detectors, acoustic sensors, temperature and humidity sensors, light detectors, and chemical sensors, will be explored in detail. The course also introduces advanced topics, including sensor materials, fabrication technologies, and wireless sensor networks. Through lectures and hands-on activities, students will gain a strong foundation in sensor technology and its applications across engineering and scientific fields. Prereq: ECE 211 and PHYS 251. Dual-listing: ECE 628.