🚦 Traffic Control System

This project implements a Traffic Light Control System on STM32 which controls 4 traffic lights at an intersection. The system dynamically adapts to vehicle presence and count.

🔑 Features

🔹 Finite-State Machine (FSM): Manages traffic light states and transitions for real-time control.
🔹 Dynamic Signal Timing: Adjusts signal timing based on vehicle presence and count.
🔹 GPIO Interrupts: Utilizes interrupt-driven button presses for vehicle counting.
🔹 RGB LED Control: Drives traffic light simulating LEDs using GPIO outputs.
🔹 Bare-Metal Firmware: Implemented in C using direct register access for efficiency.
🔹 Event-Driven Architecture: Low-power idle until vehicle detection enables real-time processing.

🏗 System Architecture

                                     |  |  │  |  |
                          south-bound|  |  │  |  |
                            traffic  |  |⬇️│  |⬆️| 
                                     |  |  │  |  |
                                     |⬇️|  │⬆️|  |
                                     ── ── ── ── ─ 
                                      🚥 
               _ _ _ _ _ _ _ .       Light 2           ._ _ _ _ _ _ _ _ _ west-bound
               _ _ _ ⬅️ _  _ |                       🚦|_⬅️ _ _ _ _ _ _ _   traffic
               ___________⬅️_|                 Light 3 |_______⬅️________
    east-bound _ _ _➡️ _ _ _ |🚦                       |_➡️ _ _ _ _ _ _ _
      traffic  _ _ _ _ _➡️ _ |Light 1                  |_ _ _ _ ➡️_ _ _ _
                                             🚥 Light 4
                                     ── ── ── ── ─ 
                                     |⬇️|  │  |⬆️|
                                     |  |  │  |  | north-bound 
                                     |  |⬇️│⬆️|  |   traffic
                                     |  |  │  |  |
                                     |  |  │  |  |

🔄 Traffic Light Synchronization

Light 1 and Light 3 are synchronized, operating in tandem to manage east-west traffic flow.
Light 2 and Light 4 are synchronized, controlling north-south traffic flow.

💡 Example Serial Terminal Output

other outputs above...
Light 1-3: RED (east-west traffic stopped)   
Light 2-4: GREEN (north-south traffic allowed) 

Light 1 car detected: 1
Light 1 car detected: 2
Light 1 car detected: 3

Light 2-4: YELLOW (caution, changing soon)
Light 2-4: RED (north-south traffic stopped)
Light 1-3: GREEN (east-west traffic allowed)
... continues with other outputs

🛠️ Development Tools & Software

🕹️ Microcontroller Development
   ⎔ VS Code - Primary code editor for STM32 firmware development
   ⎔ OpenOCD - Used for flashing and debugging over SWD
   ⎔ Makefile - Handles compilation, linking, and build automation
⚙️ Hardware
   ⎔ STM32 MCU - Microcontroller used to control the traffic light system
   ⎔ RGB LEDs - Simulate the traffic lights
      • Used Red and Green LEDs; combined them to create Yellow
   ⎔ Resistors - Used to limit current and protect components
   ⎔ Breadboards - Used for prototyping and testing the traffic light system

⛓️ Hardware Connection

RGB LED Connections:
    • Common anode pins connected to ground (active-low configuration)
    • Red and green channels driven by dedicated GPIO outputs
    • Yellow state achieved by simultaneously activating both red and green channels
Button Connections:
    • Tactile switches connected to GPIO input pins with internal pull-up resistors
    • Pressing a button pulls the input low, triggering a vehicle detection interrupt

📍 Pin Assignments

LIGHT	RED	GREEN	BUTTON
Light 1	PB10	PB4	PC10
Light 2	PB5	PB3	PC11
Light 3	PB2	PB1	PC12
Light 4	PB14	PB13	PC13

Demo