import RPi.GPIO as GPIO import time #GPIO.cleanup() GPIO.setmode(GPIO.BCM) YELLOW = 18 GPIO.setup(YELLOW, GPIO.OUT) pin = GPIO.PWM(YELLOW, .1) pin.start(0) for i in range(1,21): pin.ChangeDutyCycle(1.75 * i ) time.sleep(2) pin.stop() GPIO.output(YELLOW, 0) GPIO.cleanup()