Making a buzzer sound.

 

import RPi.GPIO as GPIO

import time

buzzer_pin = 18

GPIO.setmode (GPIO.BCM)

GPIO.setup (buzzer_pin, GPIO.OUT)

def buzz (pitch, duration):

    print ("Pitch is " + str(pitch) + "Hz")

    print ("Duration is " + str(duration) + "seconds")

    period = 1.0 / pitch

    #Trace period = 1/1000 = 0.001

    print ("Period is " + str(period) + "seconds")

    delay = period / 2

    #Trace delay = 0.001/2 = 0.0005

    cycles = int (duration * pitch)

    #Trace cycles = 4 * 1000 = 4000

    print ("Cycles are " + str(cycles))

    #range function returns a sequence of numbers

    for i in range (cycles):

        GPIO.output (buzzer_pin, True)

        time.sleep(delay)

        GPIO.output (buzzer_pin, False)

        time.sleep(delay)

try:

    while True:

        #Change to raw_input for python

        pitch_s = input ("Enter Pitch 200 to 2000 ")

        #Trace pitch = 1000

        pitch = float (pitch_s)

        duration_s = input ("Enter duration seconds ")

        #Trace duration  = 4

        duration = float (duration_s)

        buzz (pitch, duration)

        

finally:

    print ("Cleaning Up")

    GPIO.cleanup()

    print ("Done Cleaning Up")

As an extra activity see if you can use the Pulse Width Modulation code to do the same thing.