.. note:: Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts. **Why Join?** - **Expert Support**: Solve post-sale issues and technical challenges with help from our community and team. - **Learn & Share**: Exchange tips and tutorials to enhance your skills. - **Exclusive Previews**: Get early access to new product announcements and sneak peeks. - **Special Discounts**: Enjoy exclusive discounts on our newest products. - **Festive Promotions and Giveaways**: Take part in giveaways and holiday promotions. 👉 Ready to explore and create with us? Click [|link_sf_facebook|] and join today! .. _py_pa_buz: 3.2 Custom Tone ========================================== We have used active buzzer in the previous project, this time we will use passive buzzer. Like the active buzzer, the passive buzzer also uses the phenomenon of electromagnetic induction to work. The difference is that a passive buzzer does not have oscillating source, so it will not beep if DC signals are used. But this allows the passive buzzer to adjust its own oscillation frequency and can emit different notes such as "doh, re, mi, fa, sol, la, ti". Let the passive buzzer emit a melody! **Required Components** In this project, we need the following components. It's definitely convenient to buy a whole kit, here's the link: .. list-table:: :widths: 20 20 20 :header-rows: 1 * - Name - ITEMS IN THIS KIT - LINK * - ESP32 Starter Kit - 320+ - |link_esp32_starter_kit| You can also buy them separately from the links below. .. list-table:: :widths: 30 20 :header-rows: 1 * - COMPONENT INTRODUCTION - PURCHASE LINK * - :ref:`cpn_esp32_wroom_32e` - |link_esp32_wroom_32e_buy| * - :ref:`cpn_esp32_camera_extension` - |link_esp32_extension_board| * - :ref:`cpn_breadboard` - |link_breadboard_buy| * - :ref:`cpn_wires` - |link_wires_buy| * - :ref:`cpn_resistor` - |link_resistor_buy| * - :ref:`cpn_buzzer` - \- * - :ref:`cpn_transistor` - |link_transistor_buy| **Available Pins** Here is a list of available pins on the ESP32 board for this project. .. list-table:: :widths: 5 20 * - Available Pins - IO13, IO12, IO14, IO27, IO26, IO25, IO33, IO32, IO15, IO2, IO0, IO4, IO5, IO18, IO19, IO21, IO22, IO23 **Schematic** .. image:: ../../img/circuit/circuit_3.1_buzzer.png :width: 500 :align: center When the IO14 output is high, after the 1K current limiting resistor (to protect the transistor), the S8050 (NPN transistor) will conduct, so that the buzzer will sound. The role of S8050 (NPN transistor) is to amplify the current and make the buzzer sound louder. In fact, you can also connect the buzzer directly to IO14, but you will find that the buzzer sound is smaller. **Wiring** Two types of buzzers are included in the kit. We need to use active buzzer. Turn them around, the sealed back (not the exposed PCB) is the one we want. .. image:: ../../components/img/buzzer.png :width: 500 :align: center The buzzer needs to use a transistor when working, here we use S8050 (NPN Transistor). .. image:: ../../img/wiring/3.1_buzzer_bb.png **Code** .. note:: * Open the ``3.2_custom_tone.py`` file located in the ``esp32-starter-kit-main\micropython\codes`` path, or copy and paste the code into Thonny. Then, click "Run Current Script" or press F5 to execute it. * Make sure to select the "MicroPython (ESP32).COMxx" interpreter in the bottom right corner. .. code-block:: python import machine import time # Define the frequencies of several musical notes in Hz C4 = 262 D4 = 294 E4 = 330 F4 = 349 G4 = 392 A4 = 440 B4 = 494 # Create a PWM object representing pin 14 and assign it to the buzzer variable buzzer = machine.PWM(machine.Pin(14)) # Define a tone function that takes as input a Pin object representing the buzzer, a frequency in Hz, and a duration in milliseconds def tone(pin, frequency, duration): pin.freq(frequency) # Set the frequency pin.duty(512) # Set the duty cycle time.sleep_ms(duration) # Pause for the duration in milliseconds pin.duty(0) # Set the duty cycle to 0 to stop the tone # Play a sequence of notes with different frequency inputs and durations tone(buzzer, C4, 250) time.sleep_ms(500) tone(buzzer, D4, 250) time.sleep_ms(500) tone(buzzer, E4, 250) time.sleep_ms(500) tone(buzzer, F4, 250) time.sleep_ms(500) tone(buzzer, G4, 250) time.sleep_ms(500) tone(buzzer, A4, 250) time.sleep_ms(500) tone(buzzer, B4, 250) **How it works?** If the passive buzzer given a digital signal, it can only keep pushing the diaphragm without producing sound. Therefore, we use the ``tone()`` function to generate the PWM signal to make the passive buzzer sound. This function has three parameters: * ``pin``: The pin that controls the buzzer. * ``frequency``: The pitch of the buzzer is determined by the frequency, the higher the frequency, the higher the pitch. * ``Duration``: The duration of the tone. We use the ``duty()`` function to set the duty cycle to 512(about 50%). It can be other numbers, and it only needs to generate a discontinuous electrical signal to oscillate. **Learn More** We can simulate specific pitches and thus play a complete piece of music. .. note:: * Open the ``3.2_custom_tone_music.py`` file located in the ``esp32-starter-kit-main\micropython\codes`` path, or copy and paste the code into Thonny. Then, click "Run Current Script" or press F5 to execute it. * Make sure to select the "MicroPython (ESP32).COMxx" interpreter in the bottom right corner. .. code-block:: python import machine import time # Define the GPIO pin that is connected to the buzzer buzzer = machine.PWM(machine.Pin(14)) # Define the frequencies of the notes in Hz C5 = 523 D5 = 587 E5 = 659 F5 = 698 G5 = 784 A5 = 880 B5 = 988 # Define the durations of the notes in milliseconds quarter_note = 250 half_note = 300 whole_note = 1000 # Define the melody as a list of tuples (note, duration) melody = [ (E5, quarter_note), (E5, quarter_note), (F5, quarter_note), (G5, half_note), (G5, quarter_note), (F5, quarter_note), (E5, quarter_note), (D5, half_note), (C5, quarter_note), (C5, quarter_note), (D5, quarter_note), (E5, half_note), (E5, quarter_note), (D5, quarter_note), (D5, half_note), (E5, quarter_note), (E5, quarter_note), (F5, quarter_note), (G5, half_note), (G5, quarter_note), (F5, quarter_note), (E5, quarter_note), (D5, half_note), (C5, quarter_note), (C5, quarter_note), (D5, quarter_note), (E5, half_note), (D5, quarter_note), (C5, quarter_note), (C5, half_note), ] # Define a function to play a note with the given frequency and duration def tone(pin,frequency,duration): pin.freq(frequency) pin.duty(512) time.sleep_ms(duration) pin.duty(0) # Play the melody for note in melody: tone(buzzer, note[0], note[1]) time.sleep_ms(50) * The ``tone`` function sets the frequency of the pin to the value of ``frequency`` using the ``freq`` method of the ``pin`` object. * It then sets the duty cycle of the pin to 512 using the ``duty`` method of the ``pin`` object. * This will cause the pin to produce a tone with the specified frequency and volume for the duration of ``duration`` in milliseconds using the ``sleep_ms`` method of the time module. * The code then plays a melody by iterating through a sequence called ``melody`` and calling the ``tone`` function for each note in the melody with the note's frequency and duration. * It also inserts a short pause of 50 milliseconds between each note using the ``sleep_ms`` method of the time module.