Raspberry Pi Multiple LEDs
Scale up from one LED to several by wiring each with its own resistor and controlling them together with gpiozero's LEDBoard class, building toward a simple traffic-light pattern.
Wiring Multiple LEDs
Each additional LED needs its own current-limiting resistor and its own GPIO pin - resistors are never shared between LEDs, because each LED draws its own current independently. All the LEDs' cathodes can share the same GND rail on the breadboard, since ground is common across the whole circuit; only the resistor-and-anode side needs a dedicated GPIO pin per LED.
The LEDBoard Class
Controlling three separate `LED` objects one at a time gets repetitive. gpiozero's `LEDBoard` class groups multiple LEDs into a single object, so you can turn them all on or off together, or address any individual LED by a name you choose when you create the board.
Creating and controlling an LEDBoard
from gpiozero import LEDBoard
lights = LEDBoard(red=17, yellow=27, green=22)
lights.on() # all three LEDs on at once
lights.off() # all three off at once
lights.red.on() # address one LED by the name you gave it
lights.value = (1, 0, 1) # tuple sets red=on, yellow=off, green=on, in pin order- Named attributes (`lights.red`, `lights.yellow`, `lights.green`) - each behaves exactly like an individual `LED` object
- `lights.value` - a tuple you can read or set to control every LED's state in one line
- `lights.on()` / `lights.off()` - control every LED on the board simultaneously
- Indexing like `lights[0]` also works, following the order the pins were declared in
A Simplified Traffic Light
A classic beginner project is a traffic light sequence: red for a while, a brief yellow transition, then green, then yellow again before returning to red. This isn't wired to any real intersection logic, but it's a good exercise in sequencing multiple outputs with timed delays - the same pattern you'd use for any multi-stage indicator.
A traffic light sequence
from gpiozero import LEDBoard
from time import sleep
lights = LEDBoard(red=17, yellow=27, green=22)
while True:
lights.red.on()
sleep(3)
lights.red.off()
lights.yellow.on()
sleep(1)
lights.yellow.off()
lights.green.on()
sleep(3)
lights.green.off()
lights.yellow.on()
sleep(1)
lights.yellow.off()Exercise: Raspberry Pi Digital Output
Before you can turn a GPIO pin HIGH or LOW to control an LED, what must you first do in code?
