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GPIO Project 3 - Traffic Light

Beginner

30 Minuten

114,90

In this project you will learn how to use multiple LEDs to simulate a traffic light. Each LED is controlled via a separate GPIO pin, and you program the logic of a traffic light.

Connection diagram

Connect the red LED:
- Long leg (anode): Connect this to GPIO 17 (pin 11).
- Short leg (katode): Connect this toGND (ground) via a jumper wire .
Connect the yellow LED:
- Long leg (anode): Connect this to GPIO 27 (pin 13).
- Short leg (cathode): Connect this toGND (ground) using a jumper wire.
Connect the green LED:
- Long leg (anode): Connect this with GPIO 22 (pin 15).
- Short leg (cathode): Connect this toGND with a jumper wire.

Pinout Reference

GPIO	Pin #	LED color	Function
GPIO 17	Pin 11	Red	Control red LED
GPIO 27	Pin 13	Yellow	Control yellow LED
GPIO 22	Pin 15	Green	Control green LED
GND	Pin 6	All LEDs	Earth/ground connection

Python-Code in Thonny

Start Thonny: Click on the Raspberry Pi menu > Programming > Thonny Python IDE.
Write your code: Create a new file in Thonny and enter the following code:

from gpiozero import LED
from time import sleep

# LED's koppelen aan GPIO-pinnen
red = LED(17)    # Rode LED op GPIO 17
yellow = LED(27) # Gele LED op GPIO 27
green = LED(22)  # Groene LED op GPIO 22

# Verkeerslicht simulatie
while True:
    # Rood licht
    red.on()
    yellow.off()
    green.off()
    sleep(3)

    # Rood en geel samen (overgang)
    red.on()
    yellow.on()
    green.off()
    sleep(1)

    # Groen licht
    red.off()
    yellow.off()
    green.on()
    sleep(3)

    # Geel knipperend (waarschuwing)
    red.off()
    yellow.on()
    green.off()
    sleep(1)
    yellow.off()
    sleep(1)

Save the file: Click on File > Save As and name the file traffic_light.py.
Run the script: Click on the green Run button (▶) at the top of the Thonny interface.

How does it work?

red.on(), yellow.on() , green.on(): Controls the respective LEDs to flash.
sleep(x): Pauses the program for x seconds between actions.
Order:
1. Red light stays on (stop).
2. Red and yellow light up together (preparation).
3. Green light turns on (driving).
4. Yellow light flashes (warning).< /span>

Result

If everything is connected correctly and the script is executed correctly, the traffic light will mimic the standard sequence of red, yellow, green.

Experimenting

Adjust Timing: Change the values of sleep(x) to change the duration of each light.
Multiple Traffic Lights: Add a second set of LEDs to simulate multiple traffic lights.