A finite-state machine is a model of computation that can simulate logic and program with a limited number of states. A traffic signal controller is a device that controls the sequence of two or more road signals. The controller is usually placed in a cabinet adjacent to the intersection. The controller uses sensors and timers. This paper describes an approach to the design of traffic signal controllers that is based on a limited-state mechanical flow simulation technique in order to enhance city traffic conditions. A controller model is composed of a series of separate parameters representing different traffic signal configurations, e.g. for main and side roads Green, Yellow or Red Phases as well as pedestrians signals. Preset conditions, such as the duration of the timer and the presence of vehicles or pedestrians, shall govern the transition between these states. The effectiveness and adaptability of our proposed controller for the management of urban traffic scenarios has been demonstrated through extensive simulations and real world implementations. Our controller contributes to improved traffic efficiency and pedestrian safety in urban environments through dynamic adjustment of traffic signal configurations based on real time conditions. Overall, a robust and responsive solution to the complex challenges of optimising traffic flow and ensuring security is offered by our FSM and IoT based traffic signal controller in modern cities .