@iiot2k/gpiox/examples/pwm_gpio.js

Input/Output on any gpio library

/*
 * example generate pwm on gpio output 
 *
 * run:
 * > node pwm_gpio.js
 *
 */


"use strict";

const gpiox = require("../gpiox");

const PIN_INPUT = 21;
const PIN_OUTPUT = 20;

const FREQUENCY = 200; // Hz
const DUTY_CYCLE1 = 30; // %
const DUTY_CYCLE2 = 50; // %
const DUTY_CYCLE3 = 70; // %

const DEBOUNCE_US = 1000; // us

console.log("*** pwm gpio node.js example ***");
console.log("stop program with Ctrl+C");

// init gpio
gpiox.init_gpio(PIN_INPUT, gpiox.GPIO_MODE_INPUT_PULLUP, DEBOUNCE_US);
gpiox.init_gpio(PIN_OUTPUT, gpiox.GPIO_MODE_OUTPUT, 0);

// depends on input generate pwm output
if (gpiox.get_gpio(PIN_INPUT))
    gpiox.pwm_gpio(PIN_OUTPUT, FREQUENCY, DUTY_CYCLE1);
else
    gpiox.pwm_gpio(PIN_OUTPUT, FREQUENCY, DUTY_CYCLE2);

console.log("frequency", gpiox.get_pwm_frequency(PIN_OUTPUT), "duty cycle", gpiox.get_pwm_dutycycle(PIN_OUTPUT));

// after 5 sec change duty cycle
var id_tout = setTimeout(function() {
    gpiox.pwm_gpio(PIN_OUTPUT, FREQUENCY, DUTY_CYCLE3);
    console.log("frequency", gpiox.get_pwm_frequency(PIN_OUTPUT), "duty cycle", gpiox.get_pwm_dutycycle(PIN_OUTPUT));
}, 5000);

// prevent stop program
var id_intv = setInterval(function() {}, 100);

process.on('SIGINT', () => {
    clearTimeout(id_tout);
    clearInterval(id_intv);
    console.log(" -> program stopped");
    process.exit();
});