RPi-Audio-Visualiser

Permet d'avoir un aperçu des bandes mono sur un écran OLED 0.96", mais peut être ajuster pour d'autres besoins.

Requirement

• Raspberry Pi (Zero v1.3)
• Écran OLED 0.91" I2C/SPI - https://www.waveshare.com/wiki/0.91inch_OLED_Module
• Capteur audio SPH0645 - https://learn.adafruit.com/adafruit-i2s-mems-microphone-breakout/raspberry-pi-wiring-test
• Raspbian OS Lite (buster)

Préparation

Installer le module audio et l'écran OLED selon le guide fournis par les liens ou selon la documentation de votre matériel.

Éditer le fichier de configuration (/boot/config.txt) comme ceci;

#Active l'I2C et SPI
dtparam=i2c_arm=on
#dtparam=i2s=on
dtparam=spi=on

#Désactive l'audio embarqué
dtparam=audio=off

#Booster le port I2C pour un rendu plus rapide
dtparam=i2c_arm_baudrate=400000

#Le microphone
dtoverlay=googlevoicehat-soundcard

Installer les pré-requis du système;

sudo apt-get update && sudo apt-get upgrade -y
sudo apt-get install -y \
  autoconf automake libtool libfftw3-dev libasound2-dev \
  libncursesw5-dev libpulse-dev libconfig-dev libi2c-dev \
  i2c-tools python3-pip python3-pil python3-dev \
  libfreetype6-dev libjpeg-dev build-essential git
cd ~
git clone https://github.com/karlstav/cava.git
cd cava
./autogen.sh
./configure
make
sudo make install
pip3 install luma.oled

Ajuster Cava pour avoir les configs de base requis, éditer le fichier /home/pi/.config/cava/config ;

## Configuration file for CAVA.
# Remove the ; to change parameters.
[general]
# Accepts only non-negative values.
framerate =  25
autosens = 0
sensitivity = 5000
bars = 64
lower_cutoff_freq = 60
higher_cutoff_freq = 20000

[input]
method = alsa
source = hw:0,0
framerate = 25
buffer = 256
sample_bits = 8

[output]
method = raw
raw_target = /tmp/cava.fifo
data_format = ascii
channels = mono

[smoothing]
;integral = 0
;gravity = 100
;noise_reduction = 50

Script de visualisation audio

Créer et insérer dans le fichier /home/pi/oledlive.py

import os
import select
from PIL import Image, ImageDraw
from luma.core.interface.serial import i2c
from luma.oled.device import ssd1306

WIDTH, HEIGHT = 128, 32
EXPECTED_BARS = 64
FIFO_PATH = "/tmp/cava.fifo"

serial = i2c(port=1, address=0x3C)
device = ssd1306(serial, width=WIDTH, height=HEIGHT)

try:
    fifo_fd = os.open(FIFO_PATH, os.O_RDONLY | os.O_NONBLOCK)
except FileNotFoundError:
    exit(1)

buffer = ""
bar_width = WIDTH // EXPECTED_BARS
img = Image.new('1', (WIDTH, HEIGHT))
draw = ImageDraw.Draw(img)

while True:
    rlist, _, _ = select.select([fifo_fd], [], [])
    if fifo_fd in rlist:
        try:
            data = os.read(fifo_fd, 2048)
            if not data:
                continue
            buffer += data.decode(errors='ignore')
            lines = buffer.split('\n')
            buffer = lines[-1] if buffer[-1] != '\n' else ""

            for line in lines[:-1]:
                vals = line.strip().split(';')
                if len(vals) < EXPECTED_BARS:
                    continue

                # Parsing optimisé
                values = []
                append = values.append
                for v in vals[:EXPECTED_BARS]:
                    try:
                        append(int(v))
                    except:
                        append(0)

                # Dessin rapide
                draw.rectangle((0, 0, WIDTH, HEIGHT), fill=0)
                for i, val in enumerate(values):
                    bar_height = max(1, val * HEIGHT // 200)
                    x0 = i * bar_width
                    x1 = x0 + bar_width - 1
                    draw.rectangle((x0, HEIGHT - bar_height, x1, HEIGHT), fill=255)

                device.display(img)

        except OSError:
            continue

Alléger le système

Ceci va ajuster le système pour donner plus de puissance, surtout avec un RPi Zero v1.

udo systemctl disable --now \
    avahi-daemon \
    bluetooth \
    triggerhappy \
    rsyslog \
    systemd-timesyncd \
    fake-hwclock

sudo systemctl disable getty@tty2.service getty@tty3.service \
    getty@tty4.service getty@tty5.service getty@tty6.service

sudo dphys-swapfile swapoff
sudo systemctl disable dphys-swapfile

sudo apt purge --auto-remove \
    triggerhappy \
    logrotate \
    dphys-swapfile \
    rsyslog \
    fake-hwclock \
    manpages \
    man-db \
    avahi-daemon \
    bluez \

sudo journalctl --vacuum-size=10M
sudo sed -i 's/#Storage=auto/Storage=volatile/' /etc/systemd/journald.conf
sudo systemctl restart systemd-journald

Pour désactiver le HDMI, éditer /etc/rc.local ;

/opt/vc/bin/tvservice -o
exit 0