Four way traffic light signal using PIC16F84A microcontroller:

Hi friends, today we are going to make a four way traffic light controller using a PIC16F84 microcontroller. In this project we will operate three LEDs (RED, YELLOW, and GREEN) according to the traffic rules.

  • Illumination of the green light allows traffic to proceed in the direction denoted,
  • Illumination of the yellow light denoting, if safe to do so, prepare to stop short of the intersection, and
  • Illumination of the red signal prohibits any traffic from proceeding.Four way traffic light signal using PIC16F84A microcontroller

four way traffic contoll using PIC16F84A microcontroller


1)      Four set of Red-Green-Blue LEDs

2)      PIC16F84A microcontroller

3)      22uF capacitor – 2 no.

4)      Crystal oscillator 4MHz

5)      10KΩ resistor, 330Ω resistors

6)      5V battery


1)      In this project we are going to operate (control) a four way traffic light signal using PIC16F84A microcontroller. First thing we have to do is , simply connect four set of Red-Green-Yellow LEDs to respective pins of  PIC16F84A microcontroller as shown in circuit diagram(you can also use separate LEDs just connect all common terminals (negative) to ground with 330Ω resistor in series with each LED).Four way traffic light signal using PIC16F84A microcontroller schematic

2)      5V supply to the pin number 14.

3)      Ground pin number 5.

4)      Connect two 22uF capacitors in parallel with two terminals of crystal oscillator.

5)      Make all the remaining connection as shown in figure.

Click below link to download .C and .HEX files for this project



Source : Four way traffic light signal using PIC16F84A microcontroller:

About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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