3.5. The LED class

The simplest piece of hardware on the camera is its on-board LEDs. Most boards have an RGB LED (red, green, blue). machine.LED is the dedicated class for controlling them; no pin number, no resistor, no circuit – the lookup, current limiting, and wiring are handled by the camera itself.

import time
from machine import LED

red = LED("LED_RED")
red.on()
time.sleep(5)
red.off()

A complete hardware “hello world”: import the class, construct an instance with the colour’s name, turn it on, wait, turn it off. The LED is visibly lit during the five-second sleep.

The closing red.off() is symmetric to the opening red.on() and makes the cleanup explicit. The on-board LEDs also reset automatically when the script exits. As scripts grow, relying on script-exit cleanup gets fragile; making each .on() pair with an explicit .off() is the habit that keeps long scripts predictable.

3.5.1. Constructor and methods

The constructor takes one of "LED_RED", "LED_GREEN", or "LED_BLUE". Each instance exposes four methods:

  • on() – turn it on.

  • off() – turn it off.

  • toggle() – flip the current state.

  • value() – with no arguments, return the current state (0 or 1); with one argument, set it.

A blinker, using the main-loop pattern:

import time
from machine import LED

led = LED("LED_RED")

while True:
    led.toggle()
    time.sleep_ms(500)

Use the on-board LEDs for indicator and status purposes: a heartbeat that blinks every second, a red flash on error, a green pulse when a sensor reading is in range.