Imagine that you require to create a robot that will roll up close to a light lamp and stop a fixed distance from it. The first question is, how will we get electrical signals to relate to the physical process of light readings and robot wheel motion? There is a bigger part of electrical engineering based to the design of physical machines that interconnect to the physical world in such a way that some electrical characteristics of the machine based on a physical phenomenon in the world. As like, a light-sensitive resistor is a sensor whose resistance modification relaying on light intensity impinging on it; a motor is an effectors whose rotor velocity is based to the voltage across its two rods. In this course, we will not calculate the detailed physics of sensors and effectors, but will concentrate on different of building systems that use sensors and effectors to perform both simple and more complicated programs. To get a robot to halt in front of a light lamp, the problem will be to search a way to connect the photo-resistor to the motor, so that the robot will halt at an appropriate distance from the lamp. Thus, we will already use the concept of abstraction to treat sensors and operations as primitive modules whose internal information we may ignore, and whose performance properties we may use as we design systems create on these components.