ESP32 Soundboard

Soundboard (computer program), a web application or computer program with buttons that play short, often humorous sound clips.

Hardware

• ESP32 µC
• MAX98357A PCM Input Class D Audio Power Amplifiers
• [SD card]

Wiring

SD card

SD card pin	ESP32 pin	Notes
CS	GPIO05
DI	GPIO23 (MOSI)
SCK	GPIO18 (SCK)
DO	GPIO19 (MISO)
CD	GPIO17	optional

Touch

ESP32 Touch pad	GPIO	Notes
T0	04
T1	00	also bootloader (not usable on dev board)
T2	02	also bootloader (not usable on dev board)
T3	15
T4	13
T5	12
T6	14
T7	27
T8	33
T9	32

I2S

MAX98357A	ESP32 pin
LRC	25
BCLK	26
DIN	22
GAIN	(VCC)
SD	-

Build

git clone https://dev.xd0.de/hendrik/soundboard.git
cd soundboard
virtualenv .
source bin/activate
pip install -U platformio
platformio run -t upload && platformio device monitor -b 115200

• Convert mp3 files: sox ~/Music/input.mp3 -c 1 -r 11025 -b 16 output.wav trim 0 30
• SD card is tested with one FAT16 partion

ToDo

• Prototype
• reimplement tasks with a queue, see i2s_push_sample() from esp-idf/components/driver/i2s.c
• Keypad layout
• internal DAC?
• Add-ons?
• dynamic keypad thresholds
• wav file headers
• stack size in play task

References