Wiznet makers

1) Introduction

The Loud Raspberry Pi Media Center is a compact network audio device built around a Raspberry Pi Zero / Zero 2 W, a dual MAX98357A I2S DAC with integrated Class-D amplifier, and a WIZnet W5500 SPI Ethernet controller. It is designed as a small but practical home media center that can directly drive passive speakers while also providing reliable wired network connectivity.

Unlike simple Bluetooth speakers or Wi-Fi-only streamers, this design focuses on open hardware, Linux-based audio software, and stable Ethernet streaming. The onboard W5500 gives the Raspberry Pi Zero platform a wired network path through SPI, which is useful for multi-room audio, smart home alerts, TTS playback, and always-on embedded audio nodes.

The board is intended to support software such as Volumio, Mopidy, and custom Raspberry Pi OS-based firmware. The original project notes that enabling the DAC, Ethernet, and IR receiver can be handled with only a few Device Tree overlay lines in the Raspberry Pi boot configuration.

This article explains how the project works, why WIZnet W5500 is useful in a media-center design, how the hardware interfaces are arranged, and how to configure the software stack for testing.

2) Required Components

Main Hardware

The Loud Raspberry Pi Media Center version is listed as compatible with Raspberry Pi Zero W and Raspberry Pi Zero 2 W. It uses a dual MAX98357 DAC/amplifier stage and provides 5W per channel into 4Ω or 3W per channel into 8Ω according to the product specification.

Software

Recommended software options:

The project repository also describes Ansible-based provisioning for services such as PulseAudio, Spotify Connect, Snapcast, AirPlay, Squeezelite, UPnP/DLNA, CamillaDSP, and display/LED visualizers.

3) Hardware Setup

The hardware architecture can be understood as four blocks:

1. Raspberry Pi Zero host
   Runs Linux, audio services, network services, and user applications.
2. WIZnet W5500 Ethernet controller
   Provides SPI-based wired Ethernet connectivity.
3. MAX98357A I2S DAC/Class-D amplifier
   Receives digital audio from Raspberry Pi over I2S and directly drives passive speakers.
4. User interface peripherals
   IR input, RGB LED, relay enable, and serial bridge.

The board receives power from a 5V USB-C power adapter, with the Loud Media Center specification indicating a power requirement of up to 3A. The product page also notes that the Loud boards are intended for passive speakers, not headphones or external amplifiers.

Recommended Setup Flow

1. Insert Raspberry Pi Zero / Zero 2 W into the board.
2. Connect passive speakers to the speaker terminals.
3. Insert a prepared microSD card.
4. Connect Ethernet cable to the W5500 Ethernet port.
5. Connect 5V USB-C power.
6. Boot and verify audio + network interfaces.

4) Interface Explanation

I2S Audio Interface

The MAX98357A uses the Raspberry Pi’s I2S output. I2S separates audio into clock, word select, and data signals:

For the Loud Raspberry Pi Media Center, the source pinout shows the Raspberry Pi Zero using GPIO18 for I2S clock, GPIO21 for I2S data, GPIO19 for I2S word select, and GPIO4 for MAX98357A enable in the Media Center model.

SPI Ethernet Interface

The W5500 is connected over SPI. In this project, SPI is used for wired Ethernet rather than a display or storage device.

The board pinout lists SPI CLK on BCM11, MOSI on BCM10, MISO on BCM9, LAN reset on BCM24, LAN CS on BCM8, and LAN interrupt on BCM25.

IR Input

The IR receiver input is connected to BCM23. It can be enabled using the Raspberry Pi gpio-ir overlay.

RGB LED

The WS2812 RGB LED signal is connected to BCM12. It can be used for status indication, playback state, boot state, network state, or smart home notifications.

UART / Serial Bridge

The Media Center version includes an onboard serial bridge according to the product comparison table. This is useful for debugging headless installations where HDMI and USB keyboard access are not convenient.

5) Wiring Table

Raspberry Pi Zero Pin Mapping

This wiring follows the published board pinout for the Loud Raspberry Pi Media Center and Raspberry Pi Media Center hardware family.

6) Software Environment Setup

Option A: Raspberry Pi OS

Flash Raspberry Pi OS Lite to the microSD card, then mount the boot partition and edit:

/boot/config.txt

For newer Raspberry Pi OS images, the path may be:

/boot/firmware/config.txt

Add the following lines:

dtoverlay=gpio-ir,gpio_pin=23
dtoverlay=w5500
dtoverlay=max98357a,sdmode-pin=4

These lines enable the IR receiver, W5500 Ethernet controller, and MAX98357A DAC/amplifier. The same overlay configuration is documented in the product page and GitHub project for the Loud Raspberry Pi Media Center.

Then boot the Raspberry Pi and update packages:

sudo apt update
sudo apt upgrade -y

Install audio and network test tools:

sudo apt install -y alsa-utils pulseaudio-utils net-tools iproute2 python3-pip

Option B: Volumio

For Volumio, select the appropriate DAC model in the audio settings. The project documentation notes that for HiFi and Loud Raspberry models, Volumio setup is relatively simple because the DACs are supported out of the box; for Loud Raspberry, the relevant DAC setting is Adafruit MAX98357. To enable W5500 Ethernet manually, the documentation shows adding dtoverlay=w5500 to /boot/userconfig.txt.

Example:

[all]
dtoverlay=w5500

Option C: Custom Audio Node

For a custom audio endpoint, install only the services you need:

sudo apt install -y mpd mpc
sudo systemctl enable mpd
sudo systemctl start mpd

For multi-room playback:

sudo apt install -y snapclient
sudo systemctl enable snapclient
sudo systemctl start snapclient

7) Full Code Examples

7.1 Complete /boot/config.txt Hardware Configuration

# Enable IR receiver on GPIO23
dtoverlay=gpio-ir,gpio_pin=23

# Enable WIZnet W5500 SPI Ethernet controller
dtoverlay=w5500

# Enable MAX98357A I2S DAC / Class-D amplifier
# Loud Raspberry Pi Media Center uses GPIO4 as sdmode/enable pin
dtoverlay=max98357a,sdmode-pin=4

# Optional: enable UART console for debugging
enable_uart=1

7.2 Check Ethernet Interface

After booting, check whether the W5500 network interface appears:

ip addr

Check kernel messages:

dmesg | grep -i w5500
dmesg | grep -i eth

Test network connection:

ping -c 4 8.8.8.8
ping -c 4 maker.wiznet.io

7.3 Check Audio Device

List ALSA playback devices:

aplay -l

Play a test sound:

speaker-test -t sine -f 1000 -c 2

For WAV playback:

aplay test.wav

7.4 Python Network Status Test

#!/usr/bin/env python3
import socket
import subprocess

def get_ip_address():
    try:
        result = subprocess.check_output(
            ["hostname", "-I"],
            text=True
        ).strip()
        return result
    except subprocess.CalledProcessError:
        return "No IP address found"

def check_connection(host="maker.wiznet.io", port=80, timeout=3):
    try:
        with socket.create_connection((host, port), timeout=timeout):
            return True
    except OSError:
        return False

if __name__ == "__main__":
    print("Device IP:", get_ip_address())

    if check_connection():
        print("Ethernet connection: OK")
    else:
        print("Ethernet connection: FAILED")

Run:

python3 ethernet_check.py

7.5 Python Audio Playback Test

#!/usr/bin/env python3
import subprocess
import sys

def play_test_tone():
    cmd = [
        "speaker-test",
        "-t", "sine",
        "-f", "1000",
        "-c", "2",
        "-l", "1"
    ]

    try:
        subprocess.run(cmd, check=True)
        print("Audio test completed.")
    except subprocess.CalledProcessError:
        print("Audio test failed.")
        sys.exit(1)

if __name__ == "__main__":
    play_test_tone()

Run:

python3 audio_test.py

7.6 WS2812 RGB LED Status Example

Install library:

sudo pip3 install rpi_ws281x --break-system-packages

Example code:

#!/usr/bin/env python3
from rpi_ws281x import PixelStrip, Color
import time

LED_COUNT = 1
LED_PIN = 12
LED_FREQ_HZ = 800000
LED_DMA = 10
LED_BRIGHTNESS = 64
LED_INVERT = False
LED_CHANNEL = 0

strip = PixelStrip(
    LED_COUNT,
    LED_PIN,
    LED_FREQ_HZ,
    LED_DMA,
    LED_INVERT,
    LED_BRIGHTNESS,
    LED_CHANNEL
)

strip.begin()

def set_color(r, g, b):
    strip.setPixelColor(0, Color(r, g, b))
    strip.show()

try:
    set_color(0, 0, 255)   # Blue: booting
    time.sleep(1)

    set_color(0, 255, 0)   # Green: ready
    time.sleep(1)

    set_color(255, 0, 0)   # Red: alert
    time.sleep(1)

    set_color(0, 0, 0)     # Off

except KeyboardInterrupt:
    set_color(0, 0, 0)

Run:

sudo python3 led_status.py

8) Testing Steps

Step 1: Confirm Boot

uname -a

Confirm that the Raspberry Pi boots normally.

Step 2: Confirm W5500 Ethernet

ip link

Expected result: an Ethernet interface such as eth0 should appear.

Then test DHCP:

ip addr show eth0

Step 3: Confirm Internet Access

ping -c 4 maker.wiznet.io

If DNS fails, test with an IP address:

ping -c 4 8.8.8.8

Step 4: Confirm Audio Output

aplay -l
speaker-test -t wav -c 2

Start with low volume. The MAX98357A output is intended to drive passive speakers directly.

Step 5: Confirm IR Input

Install IR tools:

sudo apt install -y ir-keytable

Check events:

sudo ir-keytable -t

Press buttons on an IR remote and check whether events appear.

Step 6: Confirm RGB LED

Run the LED test script:

sudo python3 led_status.py

9) Troubleshooting

Problem: Ethernet interface does not appear

Check whether the W5500 overlay is added:

dtoverlay=w5500

Then inspect boot logs:

dmesg | grep -i spi
dmesg | grep -i w5500

Also confirm that SPI is not disabled in Raspberry Pi configuration.

Problem: Audio device is missing

Check the MAX98357A overlay:

dtoverlay=max98357a,sdmode-pin=4

Then run:

aplay -l
dmesg | grep -i max
dmesg | grep -i i2s

Problem: No sound from speakers

Check the following:

• Speakers are passive speakers, not headphones.
• Speaker impedance is suitable.
• Volume is not muted.
• speaker-test is using the correct ALSA card.
• Power adapter can supply enough current.

The board documentation states that Loud Raspberry boards are designed to connect to passive speakers and should not be used with headphones or an external amplifier.

Problem: Random reboot or audio distortion

Use a stronger 5V USB-C power adapter. The Loud Media Center power requirement is listed as up to 3A, and the project documentation explains the power budget around Raspberry Pi Zero plus the two DAC/amplifier channels.

Problem: IR remote does not respond

Confirm the IR overlay:

dtoverlay=gpio-ir,gpio_pin=23

Then test with:

sudo ir-keytable -t

Problem: Volumio cannot use Ethernet

Create or edit:

/boot/userconfig.txt

Add:

[all]
dtoverlay=w5500

The project documentation specifically shows this method for enabling W5500 Ethernet in Volumio.

10) Use Cases & Market Potential

Smart Home Audio Node

This device can be used as a Home Assistant audio endpoint. It can play doorbell sounds, warning messages, sensor-triggered alerts, TTS announcements, or automation feedback.

Multi-Room Audio

With Snapcast, multiple devices can play synchronized audio across rooms. Wired Ethernet is especially valuable here because it reduces latency variation and packet loss compared with unstable Wi-Fi environments.

Standalone Network Music Player

With Volumio, Mopidy, MPD, or Squeezelite, the device can operate as a compact network music player for a bedroom, kitchen, office, classroom, or workshop.

Educational Platform

The project is useful for learning:

• Raspberry Pi Linux audio
• I2S digital audio
• SPI Ethernet
• Device Tree overlays
• ALSA testing
• Smart home integration
• Network streaming protocols

Commercial and Industrial Audio Alerts

The W5500-based wired network design makes the board suitable for more reliable notification systems, such as:

• Factory status audio node
• Kiosk sound output
• Museum installation
• Retail announcement device
• Classroom bell or guidance system
• Networked appliance voice-feedback module

The original product page also highlights use cases such as smart home audio, multi-room audio infrastructure, standalone network player, embedded DSP/audio processing, networked sensor/interface controller, education, and rapid prototyping.

11) Module/Chip Technical Overview

WIZnet W5500 Ethernet Controller

The W5500 is a hardwired TCP/IP Ethernet controller from WIZnet. It integrates TCP/IP processing, 10/100 Ethernet MAC, and PHY into a single chip and communicates with the host over SPI. WIZnet’s documentation states that W5500 supports SPI up to 80 MHz and protocols including TCP, UDP, IPv4, ICMP, ARP, IGMP, and PPPoE.

For a Raspberry Pi media center, W5500 provides several advantages:

• Stable wired network connection
• Reduced dependence on Wi-Fi quality
• Simple SPI hardware interface
• Good fit for always-on audio endpoints
• Useful for deterministic smart home and multi-room audio behavior

In this project, W5500 is not just an add-on network chip. It is a key part of the product concept: a compact media center that can operate reliably as a network audio device.

MAX98357A I2S DAC/Class-D Amplifier

The MAX98357A receives digital audio over I2S and converts it directly into amplified speaker output. This reduces the number of analog audio stages and makes the hardware compact.

In the Loud Raspberry Pi Media Center, the design uses dual MAX98357 DAC/amplifier channels to drive stereo passive speakers. The published product specification lists output power as 5W per channel on 4Ω speakers or 3W per channel on 8Ω speakers.

Raspberry Pi Zero / Zero 2 W

The Raspberry Pi Zero family provides a Linux environment, audio software ecosystem, and community support. The original project notes that Raspberry Pi is not as lightweight as ESP32 and takes longer to boot, but it is very strong for rapid development because many drivers and software packages already exist in the Raspberry Pi ecosystem.

Why This Architecture Works Well

The design separates responsibilities clearly:

This makes the board easy to understand, easy to configure, and flexible enough for both hobby and prototype-level deployments.

12) Conclusion

The Loud Raspberry Pi Media Center is a practical example of how WIZnet Ethernet can improve a maker audio project. By combining Raspberry Pi Zero, WIZnet W5500, and MAX98357A I2S amplifier, the project creates a compact wired network speaker platform that is suitable for smart homes, multi-room audio, educational labs, and embedded audio products.

The most important design point is the use of W5500 Ethernet. Audio streaming often depends on stable network timing, and wired Ethernet can provide a more predictable connection than Wi-Fi in many real-world installations. With Raspberry Pi OS, Volumio, Mopidy, Snapcast, or custom software, this board can become a flexible and open network audio endpoint.

For makers building reliable connected audio devices, this project is a strong reference design: simple hardware interfaces, Linux software compatibility, direct speaker output, and a WIZnet-based wired network path in one compact platform.