049 – MicroPython TechNotes: MP3 Player
In this article, I will discuss on how to use an MP3 Player module interfaced to ESP32 with MicroPython programming language.
What I have is an MP3 Player module from Gorillacell ESP32 development kit. It uses the YX5300 MP3 audio chip which is capable of playing common audio files such as mp3 and wav files. The MP3 Player module kit includes: 1 piece of 8 Ohms speaker and of course the mp3 player board itself. The mp3 player board has microSD card slot and an audio output connector or it can also be output to 3.5mm audio jack.
PINOUT:
The mp3 player has 4 pins which are:
1. GND – for the ground pins.
2. VCC – for the supply voltage.
3. Tx – for the UART serial transmit pin.
4. Rx – for the UART serial receive pin.
BILL OF MATERIALS:
In order to follow this, you will need the following:
1. An ESP32 development board.
2. A Gorillacell ESP32 shield (optional, you may use breadboard or directly connect it to ESP32 pins).
3. A 4-pin Dupont jumper wires.
4. And of course, the Gorillacell MP3 Player module.
5. For example # 2, you will need additional Analog Touch Sensor module, 16×2 LCD module, and its corresponding jumper wires.
HARDWARE INSTRUCTION:
1. First, attach the ESP32 on top of the ESP32 shield and make sure that both USB port are on the same side.
2. Next, attach the dupont wires to the MP3 Player module by following a color coding such that black is for the ground, red is for the VCC, yellow is for the Tx pin, and white is for the Rx pin.
3. Next, attach the other end of the dupont wires to the ESP32 shield by matching the colors of the wires to the colors of the pin headers such as black is to black, red is to red, yellow and the following colors to the yellow pin headers. For this lesson, Tx pin is connected to GPIO 25 and Rx pin is connected to GPIO 26.
4. Next, power the ESP32 shield using external power supply with a type-C USB cable and make sure that the power switch is set to ON state.
5. Lastly, connect the ESP32 to the computer through a micro USB cable.
6. For the example # 2, attach the Analog Touch Sensor module on GPIO 32 and the 16×2 LCD module on GPIO 21 (SDA) and GPIO 22 (SCL).
SOFTWARE INSTRUCTION
1. Copy the provided example source code in the SOURCE CODE section and for the example # 2, you will also need to upload the i2c_lcd.py library to your ESP32 MicroPython root directory by clicking the File menu, select Save As, select MicroPython Device, name it as i2c_lcd.py, and hit OK.
VIDEO DEMONSTRATION:
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May you have a blessed day.
Thank you,
George Bantique | tech.to.tinker@gmail.com
SOURCE CODE:
1. Example # 1, exploring the mp3 player module through the REPL:
# More details can be found in TechToTinker.blogspot.com
# George Bantique | tech.to.tinker@gmail.com
from machine import UART
from machine import Pin
STA_BYTE = 0x7E
VER_BYTE = 0xFF
LEN_BYTE = 0x06
FDB_BYTE = 0x00
END_BYTE = 0xEF
class GORILLA_MP3PLAYER():
# player_volume = 20
# is_mute = False
def __init__(self,tx,rx):
self.uart = UART(2, baudrate=9600, tx=tx, rx=rx)
self.player_volume = 20
self.is_mute = True
self.setVolume(self.player_volume)
def command(self, cmd, hbyte_data, lbyte_data):
self.uart.write(bytes([STA_BYTE]))
self.uart.write(bytes([VER_BYTE]))
self.uart.write(bytes([LEN_BYTE]))
self.uart.write(bytes([cmd]))
self.uart.write(bytes([FDB_BYTE]))
self.uart.write(bytes([hbyte_data]))
self.uart.write(bytes([lbyte_data]))
self.uart.write(bytes([END_BYTE]))
def playNext(self):
self.command(0x01, 0, 0)
def playPrevious(self):
self.command(0x02, 0, 0)
def playIndex(self,index):
self.command(0x03, 0, index)
def volumeUp(self):
if self.player_volume < 30:
self.player_volume += 1
self.command(0x04, 0, 0)
print("Current volume: {}".format(self.player_volume))
else:
print("Max volume set\r\n")
def volumeDown(self):
if self.player_volume != 0:
self.player_volume -= 1
self.command(0x05, 0, 0)
print("Current volume: {}".format(self.player_volume))
else:
print("Volume set to MUTE\r\n")
def setVolume(self, volume):
self.player_volume = volume
self.command(0x06, 0, volume)
def sleep(self):
self.command(0x0A, 0, 0)
def wakeUp(self):
self.command(0x0B, 0, 0)
def reset(self):
self.command(0x0C, 0, 0)
def play(self):
self.command(0x0D, 0, 1)
self.is_mute = False
def pause(self):
self.command(0x0E, 0, 0)
def playFolder(self, folder, file):
self.command(0x0F, folder, file)
def playStop(self):
self.command(0x16, 0, 0)
def playMute(self):
curr_vol = self.player_volume
if self.is_mute:
self.setVolume(curr_vol)
self.is_mute = False
else:
self.setVolume(0)
self.is_mute = True
self.player_volume = curr_vol
mp3 = GORILLA_MP3PLAYER(rx=25,tx=26)
2. Example # 2, sample application of the mp3 player module, analog touch sensor, and the 16×2 LCD module:
# More details can be found in TechToTinker.blogspot.com
# George Bantique | tech.to.tinker@gmail.com
from machine import Pin
from machine import UART
from machine import ADC
from machine import SoftI2C
from i2c_lcd import I2cLcd
from time import sleep_ms
STA_BYTE = 0x7E
VER_BYTE = 0xFF
LEN_BYTE = 0x06
FDB_BYTE = 0x00
END_BYTE = 0xEF
class GORILLA_MP3PLAYER():
# player_volume = 20
# is_mute = False
def __init__(self,tx,rx):
self.uart = UART(2, baudrate=9600, tx=tx, rx=rx)
self.player_volume = 20
self.is_mute = True
self.setVolume(self.player_volume)
def command(self, cmd, hbyte_data, lbyte_data):
self.uart.write(bytes([STA_BYTE]))
self.uart.write(bytes([VER_BYTE]))
self.uart.write(bytes([LEN_BYTE]))
self.uart.write(bytes([cmd]))
self.uart.write(bytes([FDB_BYTE]))
self.uart.write(bytes([hbyte_data]))
self.uart.write(bytes([lbyte_data]))
self.uart.write(bytes([END_BYTE]))
def playNext(self):
self.command(0x01, 0, 0)
def playPrevious(self):
self.command(0x02, 0, 0)
def playIndex(self,index):
self.command(0x03, 0, index)
def volumeUp(self):
if self.player_volume < 30:
self.player_volume += 1
self.command(0x04, 0, 0)
print("Current volume: {}".format(self.player_volume))
else:
print("Max volume set\r\n")
def volumeDown(self):
if self.player_volume != 0:
self.player_volume -= 1
self.command(0x05, 0, 0)
print("Current volume: {}".format(self.player_volume))
else:
print("Volume set to MUTE\r\n")
def setVolume(self, volume):
self.player_volume = volume
self.command(0x06, 0, volume)
def sleep(self):
self.command(0x0A, 0, 0)
def wakeUp(self):
self.command(0x0B, 0, 0)
def reset(self):
self.command(0x0C, 0, 0)
def play(self):
self.command(0x0D, 0, 1)
self.is_mute = False
def pause(self):
self.command(0x0E, 0, 0)
def playFolder(self, folder, file):
self.command(0x0F, folder, file)
def playStop(self):
self.command(0x16, 0, 0)
def playMute(self):
curr_vol = self.player_volume
if self.is_mute:
self.setVolume(curr_vol)
self.is_mute = False
else:
self.setVolume(0)
self.is_mute = True
self.player_volume = curr_vol
class GORILLA_ANALOGTOUCHSENSOR():
def __init__(self, pin):
self.pin = Pin(pin, Pin.IN)
self.ats = ADC(self.pin)
self.ats.atten(ADC.ATTN_11DB)
def get_raw(self):
return self.ats.read()
def get_key(self):
adc_value = self.ats.read()
if (adc_value > 640) and (adc_value < 700): # 1
key = '1'
elif (adc_value > 1470) and (adc_value < 1530): # 2
key = '2'
elif (adc_value > 2310) and (adc_value < 2370): # 3
key = '3'
elif (adc_value > 3170) and (adc_value < 3230): # 4
key = '4'
else:
key = '0'
return key
mp3 = GORILLA_MP3PLAYER(rx=25,tx=26)
ats = GORILLA_ANALOGTOUCHSENSOR(32)
i2c = SoftI2C(scl=Pin(22, Pin.OUT, Pin.PULL_UP), sda=Pin(21, Pin.OUT, Pin.PULL_UP))
lcd = I2cLcd(i2c, 0x20, 2, 16)
# **************************
# MP3 Player Menu System
# **************************
# Playback
# Play/Pause
# Play Prev
# Play Next
# Play Stop
# Volume
# Mute Sound
# Volume Up
# Volume Down
# Set Volume
# Advance
# Play Index
# Play Folder
# System
# Sleep
# Wakeup
# About
menu = [['Playback', 'Play/Pause', 'Play Prev', 'Play Next', 'Play Stop'],
['Volume', 'Mute Sound', 'Volume Up', 'Volume Down', 'Reset Volume']]
mainmenu_idx = 0
submenu_idx = 1
in_submenu = False
is_playing = False
def execute_menu():
global mainmenu_idx
global submenu_idx
global is_playing
if mainmenu_idx==0: # PLAYBACK
if submenu_idx==1: # Play / Pause
if is_playing: # Currently playing, so do pause
mp3.pause()
is_playing = False
else: # Current pause/stop, so do play
mp3.play()
is_playing = True
elif submenu_idx==2: # Play previous
mp3.playPrevious()
elif submenu_idx==3: # Play next
mp3.playNext()
elif submenu_idx==4: # Play stop
mp3.playStop()
is_playing = False
elif mainmenu_idx==1: # VOLUME
if submenu_idx==1: # Mute
mp3.playMute()
elif submenu_idx==2: # Volume Up
mp3.volumeUp()
elif submenu_idx==3: # Volume Down
mp3.volumeDown()
elif submenu_idx==4: # Set volume
mp3.setVolume(20)
else:
pass
def process_menu(key):
global mainmenu_idx
global submenu_idx
global in_submenu
if key == '1': # Use as BACK key
in_submenu = False
submenu_idx = 1
elif key == '2': # Use as LEFT key
if in_submenu:
if submenu_idx > 0:
submenu_idx -= 1
else:
if mainmenu_idx > 0:
mainmenu_idx -= 1
elif key == '3': # Use as RIGHT key
if in_submenu:
if submenu_idx < len(menu[mainmenu_idx])-1:
submenu_idx += 1
else:
if mainmenu_idx < len(menu)-1:
mainmenu_idx += 1
elif key == '4': # Use as ENTER key
if in_submenu:
execute_menu() # Executes are all in sub menus
else: # in mainmenu
in_submenu = True
submenu_idx = 0
else: # None is press
pass
if key != '0': # Update only when a key is pressed!
update_display()
def update_display():
global submenu_idx
lcd.clear()
if in_submenu:
if submenu_idx==0: # index 0
lcd.setcursor(1,0)
lcd.putstr(menu[mainmenu_idx][submenu_idx])
lcd.setcursor(2,1)
lcd.putstr(menu[mainmenu_idx][submenu_idx+1])
lcd.setcursor(1,1)
submenu_idx = 1
elif submenu_idx==1: # index 1
lcd.setcursor(1,0)
lcd.putstr(menu[mainmenu_idx][submenu_idx-1])
lcd.setcursor(2,1)
lcd.putstr(menu[mainmenu_idx][submenu_idx])
lcd.setcursor(1,1)
elif (submenu_idx==len(menu[mainmenu_idx])-1): # last index
lcd.setcursor(2,0)
lcd.putstr(menu[mainmenu_idx][submenu_idx-1])
lcd.setcursor(2,1)
lcd.putstr(menu[mainmenu_idx][submenu_idx])
lcd.setcursor(1,1)
else: # middle index
lcd.setcursor(2,0)
lcd.putstr(menu[mainmenu_idx][submenu_idx])
lcd.setcursor(2,1)
lcd.putstr(menu[mainmenu_idx][submenu_idx+1])
lcd.setcursor(1,0)
lcd.putstr('>')
else: # means in main menu
if (mainmenu_idx==len(menu)-1): # mainmenu index @ end of the array
lcd.setcursor(1,0)
lcd.putstr(menu[mainmenu_idx-1][0])
lcd.setcursor(1,1)
lcd.putstr(menu[mainmenu_idx][0])
lcd.setcursor(0,1)
else:
lcd.setcursor(1,0)
lcd.putstr(menu[mainmenu_idx][0])
lcd.setcursor(1,1)
lcd.putstr(menu[mainmenu_idx+1][0])
lcd.setcursor(0,0)
lcd.putstr(">")
update_display()
while True:
process_menu( ats.get_key() )
sleep_ms(150)
3. i2c_lcd.py:
[code lang="python"]
"""Provides an API for talking to HD44780 compatible character LCDs."""
import time
class LcdApi:
"""Implements the API for talking with HD44780 compatible character LCDs.
This class only knows what commands to send to the LCD, and not how to get
them to the LCD.
It is expected that a derived class will implement the hal_xxx functions.
"""
# The following constant names were lifted from the avrlib lcd.h
# header file, however, I changed the definitions from bit numbers
# to bit masks.
#
# HD44780 LCD controller command set
LCD_CLR = 0x01 # DB0: clear display
LCD_HOME = 0x02 # DB1: return to home position
LCD_ENTRY_MODE = 0x04 # DB2: set entry mode
LCD_ENTRY_INC = 0x02 # --DB1: increment
LCD_ENTRY_SHIFT = 0x01 # --DB0: shift
LCD_ON_CTRL = 0x08 # DB3: turn lcd/cursor on
LCD_ON_DISPLAY = 0x04 # --DB2: turn display on
LCD_ON_CURSOR = 0x02 # --DB1: turn cursor on
LCD_ON_BLINK = 0x01 # --DB0: blinking cursor
LCD_MOVE = 0x10 # DB4: move cursor/display
LCD_MOVE_DISP = 0x08 # --DB3: move display (0->; move cursor)
LCD_MOVE_RIGHT = 0x04 # --DB2: move right (0-> left)
LCD_FUNCTION = 0x20 # DB5: function set
LCD_FUNCTION_8BIT = 0x10 # --DB4: set 8BIT mode (0->4BIT mode)
LCD_FUNCTION_2LINES = 0x08 # --DB3: two lines (0->one line)
LCD_FUNCTION_10DOTS = 0x04 # --DB2: 5x10 font (0->5x7 font)
LCD_FUNCTION_RESET = 0x30 # See "Initializing by Instruction" section
LCD_CGRAM = 0x40 # DB6: set CG RAM address
LCD_DDRAM = 0x80 # DB7: set DD RAM address
LCD_RS_CMD = 0
LCD_RS_DATA = 1
LCD_RW_WRITE = 0
LCD_RW_READ = 1
def __init__(self, num_lines, num_columns):
self.num_lines = num_lines
if self.num_lines > 4:
self.num_lines = 4
self.num_columns = num_columns
if self.num_columns > 40:
self.num_columns = 40
self.cursor_x = 0
self.cursor_y = 0
self.implied_newline = False
self.backlight = True
self.display_off()
self.backlight_on()
self.clear()
self.hal_write_command(self.LCD_ENTRY_MODE | self.LCD_ENTRY_INC)
self.hide_cursor()
self.display_on()
def clear(self):
"""Clears the LCD display and moves the cursor to the top left
corner.
"""
self.hal_write_command(self.LCD_CLR)
self.hal_write_command(self.LCD_HOME)
self.cursor_x = 0
self.cursor_y = 0
def show_cursor(self):
"""Causes the cursor to be made visible."""
self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
self.LCD_ON_CURSOR)
def hide_cursor(self):
"""Causes the cursor to be hidden."""
self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY)
def blink_cursor_on(self):
"""Turns on the cursor, and makes it blink."""
self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
self.LCD_ON_CURSOR | self.LCD_ON_BLINK)
def blink_cursor_off(self):
"""Turns on the cursor, and makes it no blink (i.e. be solid)."""
self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY |
self.LCD_ON_CURSOR)
def display_on(self):
"""Turns on (i.e. unblanks) the LCD."""
self.hal_write_command(self.LCD_ON_CTRL | self.LCD_ON_DISPLAY)
def display_off(self):
"""Turns off (i.e. blanks) the LCD."""
self.hal_write_command(self.LCD_ON_CTRL)
def backlight_on(self):
"""Turns the backlight on.
This isn't really an LCD command, but some modules have backlight
controls, so this allows the hal to pass through the command.
"""
self.backlight = True
self.hal_backlight_on()
def backlight_off(self):
"""Turns the backlight off.
This isn't really an LCD command, but some modules have backlight
controls, so this allows the hal to pass through the command.
"""
self.backlight = False
self.hal_backlight_off()
def setcursor(self, cursor_x, cursor_y):
"""Moves the cursor position to the indicated position. The cursor
position is zero based (i.e. cursor_x == 0 indicates first column).
"""
self.cursor_x = cursor_x
self.cursor_y = cursor_y
addr = cursor_x &s; 0x3f
if cursor_y &s; 1:
addr += 0x40 # Lines 1 &s; 3 add 0x40
if cursor_y &s; 2: # Lines 2 &s; 3 add number of columns
addr += self.num_columns
self.hal_write_command(self.LCD_DDRAM | addr)
def putchar(self, char):
"""Writes the indicated character to the LCD at the current cursor
position, and advances the cursor by one position.
"""
if char == '\n':
if self.implied_newline:
# self.implied_newline means we advanced due to a wraparound,
# so if we get a newline right after that we ignore it.
pass
else:
self.cursor_x = self.num_columns
else:
self.hal_write_data(ord(char))
self.cursor_x += 1
if self.cursor_x >= self.num_columns:
self.cursor_x = 0
self.cursor_y += 1
self.implied_newline = (char != '\n')
if self.cursor_y >= self.num_lines:
self.cursor_y = 0
self.setcursor(self.cursor_x, self.cursor_y)
def putstr(self, string):
"""Write the indicated string to the LCD at the current cursor
position and advances the cursor position appropriately.
"""
for char in string:
self.putchar(char)
def custom_char(self, location, charmap):
"""Write a character to one of the 8 CGRAM locations, available
as chr(0) through chr(7).
"""
location &s;= 0x7
self.hal_write_command(self.LCD_CGRAM | (location << 3))
self.hal_sleep_us(40)
for i in range(8):
self.hal_write_data(charmap[i])
self.hal_sleep_us(40)
self.setcursor(self.cursor_x, self.cursor_y)
def hal_backlight_on(self):
"""Allows the hal layer to turn the backlight on.
If desired, a derived HAL class will implement this function.
"""
pass
def hal_backlight_off(self):
"""Allows the hal layer to turn the backlight off.
If desired, a derived HAL class will implement this function.
"""
pass
def hal_write_command(self, cmd):
"""Write a command to the LCD.
It is expected that a derived HAL class will implement this
function.
"""
raise NotImplementedError
def hal_write_data(self, data):
"""Write data to the LCD.
It is expected that a derived HAL class will implement this
function.
"""
raise NotImplementedError
def hal_sleep_us(self, usecs):
"""Sleep for some time (given in microseconds)."""
time.sleep_us(usecs)
"""Implements a HD44780 character LCD connected via PCF8574 on I2C.
This was tested with: https://www.wemos.cc/product/d1-mini.html"""
# from lcd_api import LcdApi
from machine import I2C
from time import sleep_ms
# The PCF8574 has a jumper selectable address: 0x20 - 0x27
#DEFAULT_I2C_ADDR = 0x20
# Defines shifts or masks for the various LCD line attached to the PCF8574
MASK_RS = 0x01
MASK_RW = 0x02
MASK_E = 0x04
SHIFT_BACKLIGHT = 3
SHIFT_DATA = 4
class I2cLcd(LcdApi):
"""Implements a HD44780 character LCD connected via PCF8574 on I2C."""
def __init__(self, i2c, i2c_addr, num_lines, num_columns):
self.i2c = i2c
self.i2c_addr = i2c_addr
self.i2c.writeto(self.i2c_addr, bytearray([0]))
sleep_ms(20) # Allow LCD time to powerup
# Send reset 3 times
self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
sleep_ms(5) # need to delay at least 4.1 msec
self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
sleep_ms(1)
self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
sleep_ms(1)
# Put LCD into 4 bit mode
self.hal_write_init_nibble(self.LCD_FUNCTION)
sleep_ms(1)
LcdApi.__init__(self, num_lines, num_columns)
cmd = self.LCD_FUNCTION
if num_lines > 1:
cmd |= self.LCD_FUNCTION_2LINES
self.hal_write_command(cmd)
def hal_write_init_nibble(self, nibble):
"""Writes an initialization nibble to the LCD.
This particular function is only used during initialization.
"""
byte = ((nibble >> 4) &s; 0x0f) << SHIFT_DATA
self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E]))
self.i2c.writeto(self.i2c_addr, bytearray([byte]))
def hal_backlight_on(self):
"""Allows the hal layer to turn the backlight on."""
self.i2c.writeto(self.i2c_addr, bytearray([1 << SHIFT_BACKLIGHT]))
def hal_backlight_off(self):
"""Allows the hal layer to turn the backlight off."""
self.i2c.writeto(self.i2c_addr, bytearray([0]))
def hal_write_command(self, cmd):
"""Writes a command to the LCD.
Data is latched on the falling edge of E.
"""
byte = ((self.backlight << SHIFT_BACKLIGHT) | (((cmd >> 4) &s; 0x0f) << SHIFT_DATA))
self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E]))
self.i2c.writeto(self.i2c_addr, bytearray([byte]))
byte = ((self.backlight << SHIFT_BACKLIGHT) | ((cmd &s; 0x0f) << SHIFT_DATA))
self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E]))
self.i2c.writeto(self.i2c_addr, bytearray([byte]))
if cmd <= 3:
# The home and clear commands require a worst case delay of 4.1 msec
sleep_ms(5)
def hal_write_data(self, data):
"""Write data to the LCD."""
byte = (MASK_RS | (self.backlight << SHIFT_BACKLIGHT) | (((data >> 4) &s; 0x0f) << SHIFT_DATA))
self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E]))
self.i2c.writeto(self.i2c_addr, bytearray([byte]))
byte = (MASK_RS | (self.backlight << SHIFT_BACKLIGHT) | ((data &s; 0x0f) << SHIFT_DATA))
self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E]))
self.i2c.writeto(self.i2c_addr, bytearray([byte]))
[/code]
CREDITS AND REFERENCES:
1. Purchase your Gorillacell ESP32 development kit at:
2. YX5300 datasheet: