The paper discusses techniques of fault detection, fault mitigation and fault tolerance with regards to sensors and actuators. Many of these fault tolerant sensors and actuators are already in use in automotive, aerospace, defense industry and industrial robots. The fault tolerant components and their knowledge is critical for the development of safe, robust, and dependable robotic systems. The paper includes concepts and examples of these devices. The sensor discussion includes redundant sensors, self-diagnostic sensors, fail-safe sensors, sensor fusion systems, and smart sensors with embedded microcontrollers. The actuator discussion includes concepts of redundant actuators, series elastic actuators, reconfigurable self-diagnosing smart actuators, and fail-safe actuators.