Raspberry Pi Bell Ringer

pi-servo.py

#!/usr/bin/env python

import time
import RPi.GPIO as GPIO     # Importing the GPIO library
from time import sleep      # Import sleep module from time library

# Set up GPIO
servo_pin = 21 # GPIO Pin where servo is connected
GPIO.setmode(GPIO.BCM)

# Define the Pin numbering type and define Servo Pin as output pin
GPIO.setup(servo_pin, GPIO.OUT)
p = GPIO.PWM(servo_pin, 50) # PWM channel at 50 Hz frequency
p.start(0) # Zero duty cycle initially

# Hammer time!
sleep(0.4)
p.ChangeDutyCycle(6)
sleep(0.4)
p.ChangeDutyCycle(12)
sleep(0.25)
p.ChangeDutyCycle(6)
sleep(0.4)