Four-Way Traffic Light System Using CD4017 and 555 Timer IC

Four-Way Traffic Light System

I’ll guide you through a project on designing a four-way traffic light control system using the CD4017 decade counter and the 555 timer IC. This project mimics a basic traffic light controller, cycling through red, yellow, and green LEDs for each lane in a timed sequence, just like a real intersection.

Components Used:

  • 555 Timer IC: Acts as a clock pulse generator.
  • CD4017 Decade Counter: Controls the sequence of traffic lights.
  • Resistors and Capacitors: To set the timing and frequency.
  • LEDs (Red, Yellow, Green): Representing traffic light signals.
  • Breadboard: For prototyping the circuit.
  • Jumper Wires: For making connections.

Circuit Description:

The 555 Timer IC is configured in astable mode, generating clock pulses at a fixed interval. These clock pulses are fed into the CD4017, which controls the sequential operation of the traffic lights. For each clock pulse, the CD4017 changes its output, lighting up a different LED sequence representing the traffic lights.

Each lane has its own set of red, yellow, and green LEDs, and the circuit controls when each lane is stopped, warned, or allowed to proceed based on the timing set by the 555 timer.

Working Principle:

  • Clock Generation: The 555 timer continuously sends clock pulses.
  • Sequential Counting: The CD4017 counts these pulses and outputs them to its pins sequentially.
  • Traffic Light Control: The output pins of the CD4017 are connected to the traffic lights (LEDs), which switch on and off in a sequence to simulate real traffic signals.

Step-by-Step Guide:

  1. Setting Up the 555 Timer IC:
  • Connect pin 1 to ground.
  • Connect pin 8 to VCC (usually 9V).
  • Connect a resistor and capacitor between pins 6 and 2 to adjust the timing of the clock pulse (this determines the duration of each light).
  • Pin 3 of the 555 Timer outputs the clock pulse and is connected to the clock input (pin 14) of the CD4017.

     2. Connecting the CD4017:

  • The clock input (pin 14) of the CD4017 is connected to the output of the 555 Timer.
  • Connect red, yellow, and green LEDs for each direction (lane) to the output pins of the CD4017 (Q0 to Q9). Each group of three consecutive outputs (e.g., Q0 for red, Q1 for yellow, Q2 for green) represents the traffic light sequence for one direction.
  • Each LED’s negative terminal is connected to ground through a resistor to limit the current.

    3.Wiring the Traffic Lights:

  • For each direction, use three LEDs: one for red, one for yellow, and one for green.
  • The CD4017 will cycle through these outputs, lighting up the LEDs in a sequence to simulate real traffic light behavior.

Video Demonstration:

Here’s a video showing the working traffic light system:

Circuit Diagram:

 

Conclusion:

This four-way traffic light project provides a clear and easy-to-understand example of how to use the CD4017 decade counter and 555 Timer IC to control traffic lights. It’s a perfect introduction to digital logic circuits, timing circuits, and practical applications like traffic control systems.

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