Tests an LED connected via GPIO to Raspberry Pi with software defined PWM

test_led.py

#!/usr/bin/env python


import RPi.GPIO as GPIO
import time
import sys


out_pin = int(sys.argv[1])

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)

GPIO.setup(out_pin, GPIO.OUT)

time_off = 0.001


def output(out_pin, duty_cycle, time_off):
    time_on = (time_off*int(duty_cycle))/(100-int(duty_cycle))
    time.sleep(time_off)
    GPIO.output(out_pin, GPIO.HIGH)
    time.sleep(time_on)
    GPIO.output(out_pin, GPIO.LOW)
    time.sleep(0.001)


while True:
    for duty_cycle in range(100):
        output(out_pin, duty_cycle, time_off)
    for duty_cycle in range(99, -1, -1):
        output(out_pin, duty_cycle, time_off)
    time.sleep(0.1)