PWM LED

A "breathing" LEDLight-Emitting Diode effect: smoothly fades an LEDLight-Emitting Diode in and out using PWMPulse-Width Modulation. See the pwm APIApplication Programming Interface reference for the full type surface.

Hardware

• Any ESP32 board with a GPIOGeneral-Purpose Input/Output pin that supports PWMPulse-Width Modulation
• An LEDLight-Emitting Diode connected through a 220-ohm resistor
• USBUniversal Serial Bus cable

Code

import {Pwm} from 'mikro/pwm'

// GPIO 15 is the built-in LED on XIAO ESP32C6. Replace with your board's LED pin.
const LED_PIN = 15

const led = Pwm(LED_PIN, {freq: 50, duty: 0}).orPanic('Failed to set up the LED')

// Breathe: smoothly fade in and out forever
while (true) {
  const fadeIn = await led.fade(1.0, 1000)
  if (!fadeIn.ok) {
    console.error('Fade in failed:', fadeIn.error)
    break
  }

  const fadeOut = await led.fade(0.0, 1000)
  if (!fadeOut.ok) {
    console.error('Fade out failed:', fadeOut.error)
    break
  }
}

Walkthrough

1. PWMPulse-Width Modulation setup. Pwm(gpio, {freq, duty}) claims the GPIOGeneral-Purpose Input/Output pin, creates a PWMPulse-Width Modulation channel on it and returns a Result with the handle. freq sets the PWMPulse-Width Modulation frequency in Hz; duty sets the initial duty cycle (0.0 to 1.0).

2. Hardware fading. led.fade(target, durationMs) smoothly transitions the duty cycle to target over durationMs milliseconds. This runs in hardware on the ESP32's LEDCLED Controller (ESP peripheral) peripheral, so it does not block the event loop.

3. Error handling. Both fade() calls return a Promise<Result> (see Result). If something goes wrong (for example an invalid pin), the loop breaks with a clear error message.

Create project

pnpm

pnpm create mikro --template pwm-led

npm

npm create mikro -- --template pwm-led

yarn

yarn create mikro --template pwm-led

bun

bun create mikro --template pwm-led

Run it

pnpm

pnpm install
pnpm mikro flash  # only needed once per board
pnpm mikro dev

npm

npm install
npx mikro flash  # only needed once per board
npx mikro dev

yarn

yarn install
yarn mikro flash  # only needed once per board
yarn mikro dev

bun

bun install
bunx mikro flash  # only needed once per board
bunx mikro dev

The LEDLight-Emitting Diode fades smoothly in and out in a continuous breathing pattern.

View source on GitHub